The Production of Maple Sirup & Sugar in New York State
by G.H. Collingwood, J.A. Cope and M.P. Rasmussen
Cornell Extension Bulletin, 1914
Yep, out there and back then they spelled it Sirup, not Syrup. A lot of stuff here, in fact I cut great chunks out that seemed so historically and regionally specific to be of limited broad appeal. As always, if you use your noggin with this old material it should return you many rewards. LRM
Maple sirup and maple sugar are American foods – distinctly in the luxury group. As such they present increasingly attractive opportunities for the owner of a sugar grove, or “bush,” to obtain, at a time of year when other farm work is not pressing, a substantial cash return for labor and investment.
Maple Sirup and Sugar as a By-Product on the Farm
Maple sirup and sugar are produced during a period of from four to six weeks in the early spring and interfere but little with the other farm crops. The sugar season usually forms a welcome break between the comparative idleness of winter and the early spring plowing. It comes at a time when little else can be done. But after considering the long hours of tending the evaporator and the work of gathering the sap, many a man has asked himself if the results are worth the effort.
Most of the producers of maple sirup and sugar tap less than 500 trees. Considered from the point of view of the bookkeeper who figures overhead, depreciation, labor costs, and interest, very few of these small groves can show a profit. But is there anything that can be done to better advantage at that season of the year? Faced with such a question, nearly every farmer who owns a maple grove will decide that sugar and sirup making is worth while.
The producer who hangs less than 500 buckets will not find sugar making an especially profitable undertaking. For the large producer, however, an efficiently managed maple grove may return an attractive profit. This is especially true of those producers who operate the grove as a definite part of their farm.
A few characteristics of the smaller groves make the cost of production comparatively high. These should be recognized at the outset.
There are usually fewer trees per acre, so that more time is required to gather the sap.
The equipment is usually less efficient so that more time is required to boil down the sap.
In nearly every case the amount of sugar obtained from each tree tapped is less, due to inefficient methods of gathering, boiling, and packing.
An operation should show a reasonable profit to the producer after all of the so-called “business costs” have been accounted for. These include interest upon the value of the grove and the equipment, repairs, depreciation, and taxes, together with the cost of labor for men and teams, and the market value of the fuel used.
The operator should bear in mind, however, that if the woodlot remains idle, no extra return can be expected. Interest must be carried until the periodic or final return from the sale of the trees is made. In many cases the maple sirup or sugar crops can relieve this long wait by providing a profitable by-product to the main crop of lumber and firewood.
Low-grade cordwood is used for fuel with which to boil the sap. Thinnings, improvement cuttings, and even windfalls may be used for such fuel. This should be an incentive for careful management within the grove.
The cash returns usually follow a few weeks after the harvest. If the crop is well made, it need not be sold immediately but may be sorted and, under satisfactory conditions, may be collateral for a short-time loan.
The owner of a small maple grove who is without the necessary equipment should consider the proposition from every angle before investing in an evaporator, buckets, and so forth. The following questions should be answered:
Are there sufficient trees to warrant the effort?
Can the land now occupied by maple trees be economically put to a more profitable use?
What other early spring work offers higher wages to himself or his hired men?
Is there work for his team at that time which will bring in a better return?
Much of the land now occupied by sugar maples would be producing nothing if the trees were cut off. With some rearrangements of work on the farm, the time of men and teams in the sugar woods can be used with little loss to the other demands of the farm.
Like any other woodlot the maple grove will largely take care of itself. If properly tapped, it will produce an annual income, furnish the finest table sirup in the world, and under favorable circumstances will even supply the fuel to evaporate its own sugar-laden sap.
The sweet sap from which sirup and sugar can be made is common to all the native varieties of maple, but the hard, or sugar, maple, Acer saccharum, furnishes 75 per cent of the commercial sirup and sugar. This splendid forest tree grows in a commercial quantity from North Carolina and Missouri northward into the valley of the St. Lawrence River in Canada. It is a strong and vigorous grower, adapted to a wide variety of soils and is able to endure shade for many years and to maintain itself against the competition of other trees. Nearly every year it bears large quantities of highly fertile seeds whose wings assure their wide distribution by the wind. This explains why sugar maple maintains itself against the competition of other trees, and why there are so many practically pure stands in New York, Pennsylvania, New England, and the Lake States.
The hard, or sugar, maple prefers a well-drained site, but is found growing on practically all types of soil, except swamps and bare sand areas. It appears to grow especially well on glacial drifts or on rocky hillsides and benches. Climate seems to have more to do with the yield and the quality of the sap than has the soil. Sirup from the northern part of the range of the sugar maple is considered best.
Black maple, Acer nigrum, is a form of sugar maple that covers much the same territory as that already outlined. It resembles sugar maple so closely that it is usually reported under the same name. The best maple sirup and sugar is obtained from the hard maple and the black maple.
Red maple, Acer rubrum, grows from Canada to Florida and as far west as Texas. The name refers to the color of the winter buds, the flower and the leaf, perhaps also to the reddish or light chocolate color of the wood.
Silver maple, Acer saccharinum, is usually called soft maple among lumbermen and sugar makers. Nurserymen, park keepers, and others planting or selling the tree call it silver maple, because of the whiteness of the underside of the leaf, which, when blown by the wind, gives the tree a silvery appearance. It grows faster than sugar maple and is, therefore, perhaps more frequently planted, but the wood is weak and the tree is shorter lived. The silver maple occurs frequently in maple groves, or sugar bushes, in New York but can be distinguished from the hard maple by marked differences in bark, leaf, and bud.
The winter buds of the silver maple in common with the red maple are reddish, blunt, and rounding, while the sugar maple buds are brown in color, narrowly conical, and sharp pointed. On mature trees, the sugar maple bark forms long thick irregular plates, frequently curling along one edge, while the bark of the silver maple separates in long, thin flakes often turning up at both ends so that they are easily scaled off. The leaf differences of the three maples are pronounced and provide a sure means of distinguishing one from another.
Where the Maple Tree Gets Its Sugar
Food materials for plants are fundamentally the same as those for animals. Trees are large plants and obtain certain nutrient salts from soil and water. These raw materials are absorbed by the roots and are moved to all parts of the plant. From the air a gas, carbon dioxide, (the same that causes fizzing of soda water and other beverages) diffuses into the leaves thru minute openings. Likewise in the cells of the leaf tiny structures, called plastids, contain the green pigments known as chlorophyll. Within these plastids the carbon dioxide and water undergo chemical changes, and sugar results. To accomplish this, the energy supplied by sunlight is necessary.
Some of this sugar may be immediately used in the leaf but constantly there is a movement of sugar in the direction of the growing points and to the trunk and the roots. Some is transformed in the leaf to starch and is temporarily stored there. Later, when food materials are needed in another part of the tree, this starch is again transformed to sugar and it moves out of the leaf. When the leaves fall in the autumn, there remains in the leaf relatively little sugar or starch.
This manufacture of sugar in the leaf from carbon dioxide and water is one of the mysteries of nature. Each leaf may be considered as a factory for the production of sugar. The more leaves there are and the larger the leaves, the greater will be the production of sugar. It is obviously important, therefore, to maintain a large leaf area. But, with a large leaf area there is a corresponding evaporation of water. A maple tree with a trunk diameter of 15 inches is said to have a leaf area equal to one-third acre, and from such a leaf area more than 100 tons of water may evaporate during an entire season. It is, therefore, necessary that the tree have an adequate supply of water.
The sugar manufactured in the leaves gradually, but constantly, moves out of the leaves to the branches, the trunk, and the roots. Some may be used in growth and seed production, but a large part is transformed into starch and cells. There is relatively little sugar of any kind in the trunk or the roots during the winter, but toward spring the starch is gradually changed again to a simple sugar. In these living cells two simple sugars are evident, glucose and fructose (sometimes termed fruit sugar). A mixture of equal parts of glucose and fructose is termed invert sugar. Each of the sugars has the empirical formula of C6H12O6, which means that it is composed of carbon, hydrogen, and oxygen in the proportions of 6, 12, and 6. When these two sugars are combined with the loss of one molecule of water for each two molecules of sugars combining, a new sugar, termed sucrose or saccharose, is formed, more commonly called cane sugar. Incidentally cane sugar and beet sugar are the same. The formula for the reaction may be written:
C6H12O6 (glucose) + C6H12O6 (fructose) = C12H22O11 (sucrose) + H2O (water)
The sugar present in the conducting cells of the wood is sucrose, or cane sugar, and the sap which flows from the tap hole contains this particular sugar along with certain other organic compounds and inorganic salts. It is the presence of additional organic compounds that give the characteristic flavor to maple sirup.
Yield of Sap per Tree
Some of the factors which determine the amount of sap produced by a tree in one season are the size of the trees, the crown area, the condition of the forest floor, and the weather which characterizes the season. Authentic records are available of large sugar-maple trees that have produced as much as 40 gallons of sap in one season. On the other hand, in a season of unfavorable weather, it is not infrequent to get as low as 5 gallons of sap from a single tree. Perhaps a yield of 15 gallons of sap for each tree may be considered as average for the general run of sugar groves in New York.
Relation of Sap to Sirup and Sugar
The sugar content of the sap from sugar maples fluctuates. Even in the same tree it may vary with the season, depending on past growing conditions. Normal sap in an average year contains about 2 per cent of sugar. For purposes of calculating it is usually considered that 1 gallon of sirup of standard density will yield 8 pounds of sugar. Accordingly it will take from 45 to 50 gallons of sap to make 1 gallon of sirup. An average yield per tree of 15 gallons of sap with a 2 per cent sugar content would be approximately 2 ½ pounds of maple sugar or 1 ¼ quarts of maple sirup of standard density.
The Ideal Sugar Tree
An ideal sugar tree is well rooted, is surrounded by conditions which promote vigorous growth, and has trunk and limbs free from decay in order to support a heavy crown of foliage. As the maple-sugar industry is usually associated with the production of timber, an ideal sugar tree might well have a long, clear trunk that lifts the crown and that ultimately could be sawed into high-grade lumber.
The Grove or Sugar Bush
Location and Number of Trees
Any one who has boiled sap on the kitchen stove knows that a single tree will produce enough sap for a cup or more of table sirup, but a grove from which the operator expects to get considerable financial returns should have at least 500 trees, the smallest with a diameter at breast height of 12 inches. The grove should be close to the farmstead so that the work may fit in with the other farm operations. Sugar bushes which are far removed can seldom be economically operated unless there is a camp for housing the men and the horses, so that the men may spend all their time making sirup or sugar. These greater overhead charges require many trees in the grove and a large, well-equipped, evaporating plant. Camps of this type are comparatively common in the Adirondack Mountains and the adjoining foothills, but are not found in any number in the remainder of the State.
Very few groves have more than 35 trees to the acre, although there might be twice as many, for the trees must be reasonably close to give the maximum yield of sap per acre. Groves with less than 20 trees to the acre seldom show a profit, and an ideal grove might have 50 trees to an acre, each capable of being tapped. Thus, in developing a grove one must think of the possible yield per acre as well as the yield per tree.
The Forest Floor
As already brought out, the quantity and sugar content of sap produced by a sugar maple is in direct relation to the area of the crown. Another important consideration is the forest floor, for beneath it are the roots which support the trees and search for moisture. Maple sap is so largely water that a heavy flow is dependent upon a soil well supplied with available moisture. The leaves and humus of a good forest floor, together with the crown canopy, protect the ground against the sun and the drying winds. This is characteristic of natural forest soils. Excessive sunlight encourages briars and weeds, and helps to dry out the upper soil layers. Heavy seasonal demands upon the trees in the sugar bush make such a soil condition especially important. This can be maintained when the crowns are close enough to keep the direct sunlight from reaching the forest floor.
Most important of all is the exclusion of stock. Both cows and horses trample the ground and destroy the layers of leaf mold and valuable humus. Also they browse and prevent young maples from getting established to take the place of the veteran trees as they give way to cutting or to decay. Excessive grazing, like fire and too heavy cutting robs moisture from the soil, reduces the vitality of the trees, and decreases the flow of sap.
The Ideal Maple Grove
The ideal maple grove should satisfy the following requirements:
- The area should be completely filled with maple trees having fully developed crowns.
- The canopy of leafy crowns should allow little sunlight to fall upon the ground, so that scarcely any grass or weeds will grow among the litter of humus and leaves.
- There should be maple trees of all ages, with many young ones over the entire area. As the old trees mature and are cut out, the younger ones will take their places.
- Roadways thru the grove help in the collection of sap, and reduce the usual difficulties with under brush.
- Stock should be allowed in the woods for only a few weeks during the year of previous to an intended cutting. Cattle nip the tips and leaves of young trees, pack the ground around the tree roots, and destroy the protecting blanket of leaf mulch.
Exposure and Slope
Southern exposures are preferred by many producers, because there the sap runs earlier. Sirup from the first run is generally supposed to be better and brings a higher price. There should, however, be no difficulty in disposing of good sirup from any run. On northern exposures and in very dense groves the sap flow begins later and continues somewhat longer than on southern exposures. After all, the advantages of one slope over another depend upon local conditions and the point of view of the operator. Any large maple grove will probably include both north and south slopes.
Improving the Grove
Nearly all sugar-maple groves are the remnants of the original forest and have been used for sugar making because they contain a number of maple trees. Often the trees are over mature, while heavy grazing or fire has destroyed the young growth. Old age, neglect, and in many cases absolute abuse have combined to make hollow-butted, stag-headed trees. In addition, they have suffered from the sugar-maple borer, the maple leaf miner, or other insects.
If grazing animals are kept out, seedlings will be encouraged and a mulch of leaf litter and humus will accumulate. Within a few years the ground will become loose and capable of holding more moisture. This protection will stimulate dense growth of seedlings and saplings. Too often they whip the face and tear the clothes of the man who gathers the sap. Sap-collecting driveways cut thru the grove will partially correct this. Any additional inconvenience can be borne with the realization that these seedlings and saplings are the children of the forest, necessary to the maintenance of the grove.
Two of the largest operators in St. Lawrence County, New York, each of whom hangs a thousand buckets a year, believe that grazing should be excluded from the sugar bush. They believe also that the slight added cost of collecting sap, due to the presence of young growth is more than offset by the advantage of a completely shaded forest floor and young maples to take the place of the veterans.
Continued management and protection will accumulate a mass of young growth. In eight or ten years these trees will be from 6 to 8 feet high, and the struggle for supremacy will be keen. At least two-thirds of them should be removed. While they are small, the less desirable ones can be lopped off with a hatchet or a corn knife, leaving well-placed, thrifty maple saplings.
All other trees, such as beech, basswood, and hemlock, as well as stag-headed or deformed maples, should be cut out. Occasionally a promising white ash, red oak, basswood, or similar rapidly growing tree may be kept for lumber, but only when no satisfactory maples are present to fill the space. All trees in which the maple borer is working should be cut and burned or used before the following May.
Care of a Well-Stocked Grove
Culture operation in a dense stand of healthy mature trees presents a different problem from the improvements to be carried on in an old grove. There may be little immediate need of thinning because the trees have already developed their form. It is desirable, however, to make openings to encourage the growth of promising trees. The fuel and saw timber resulting from such cuttings should pay for the labor and, if the area is large enough, should be produced year after year.
An improvement cutting should be carried on with the following points in mind:
- Forest trees grow slowly and forest development takes time. For that reason the work must be continued indefinitely.
- Encourage worth-while trees.
- Take out trees which crowd the desirable maples; others may be removed from year to year after young growth is established. Forest-grown sugar maples usually have a broad, shallow root system, and windfall may result if they are suddenly required to stand alone.
- Cut out maples with small, narrow crowns, and those which are unsound or show signs of decline.
- Remove most of the young growth of trees which are not hard maples.
- Avoid heavy cuttings which will expose a large part of the forest floor to the sun and the wind.
- Leave an unthinned border at least 25 feet wide around all sides of the grove. Branchy trees and shrubs develop a “wind mantle” which serves as a safeguard against storms.
Establishing a Grove from a Thicket of Young Trees
There are groves in New York that have been tapped continuously for fifty years. With all their sturdiness, these veterans cannot live forever, and, if maple sirup and sugar is to continue as s forest crop, some thought must be given to establishing new groves. In fact, many of these old groves are deteriorating, due to excessive grazing which slowly, but effectually, help to bring about the ultimate destruction of the grove. As if heavy grazing were not enough of a handicap, many of the splendid veterans have as many as seven buckets hung on them in one season.
It has been suggested that the groves be perpetuated by encouraging the growth of young maple trees. The exclusion of livestock is often all that is necessary, but fire and insect pests must also be guarded against.
To start a new grove one can usually take advantage of the dense sapling stands which frequently come up near seed trees after grazing has been excluded (figure 14). Such stands may contain thousands of maple trees.
When the saplings are from 6 to 8 feet high they can be thinned so as to leave the largest and healthiest trees about 12 feet apart. The tops of the undesirable trees may be cut back with a sharp hatchet or a corn knife and left on the ground to decay. Three men can cut back trees in this manner at the rate of an acre a day. Such an operation is comparable to transplanting saplings or sowing seeds. It offers no immediate profits, but is cheaper and the returns are quicker.
Some points to keep in mind while thinning a young stand are:
- Choose thrifty trees capable of symmetrical crown development. They should be sound and free from forks.
- Remove all long, spindling trees likely to bend over.
- Preserve small trees of desirable species.
- Remove all competing trees other than maple. Suppressed ones may be left.
- Do not disturb the borders. Develop a “wind mantle” along all borders to exclude sun and wind.
- Thinnings in dense young stands may allow crowns of selected trees free space of 10 or 12 feet. If growing conditions are favorable, the crowns will touch in five or six years, requiring further thinnings to follow in ten years or less.
One farmer in Cattaraugus County (NY) is establishing a maple grove in this manner. The thinning was first begun when the trees were seven years old, and has been continued up to the present time. The stand is now about twenty-five years old. More than three standard cords of wood to the acre have been cut, which were used for fuel. There remain 200 well-developed, thrifty maple trees to the acre, averaging more than 25 feet in height and 4 inches in diameter. Some of the more-favored trees with plenty of light have a diameter of 7 inches and will be ready to tap in fifteen years. It will be necessary for the owner to continue thinnings to insure proper crown development. Within the next twenty years, the number of trees per acre will be reduced by one-half.
Establishing a Grove by Planting
The wide distribution of maple throughout the State and the readiness with which saplings develop under natural conditions has made hand planting generally unnecessary. There are, however, some hand-planted groves in the State that have been yielding sap for several years. The ease of transplanting has made the maple-bordered highways of New York famous throughout the east, and similar methods can be applied equally well in the grove. Cultivation is desirable, however, and it is doubtful whether a maple plantation will prosper if given as little care as is ordinarily given to a pine plantation.
Small trees not more than 2 to 3 feet high can be lifted from the near-by woods and set out early in the spring. Five- and six-foot trees were generally planted by the early settlers along the highways, and if there is no objection to the extra time and expense required to handle large stock, such trees can be used in establishing a grove.
Cultivation for the first year or two after planting will relieve the trees from the competition of grass and weeds. Since a well-developed crown is essential to good sap production, it follows that the trees may be planted as in an orchard. About 20 feet apart each way or approximately 100 to the acre should be satisfactory. The space in between may be temporarily used for other crops. Hundreds of roadside maples throughout the State spaced similarly are being tapped and give a good yield of sap.
It should be borne in mind that an essential of high-quantity production is a moisture-conserving forest floor within the grove. This can scarcely be obtained with the wide spacing. As soon as cultivation ceases, grass, weeds, and competing growth will spring up to exhaust, rather than conserve the soil moisture. Therefore, closer spacing, 6 by 6 feet, or 1200 trees to the acre, more nearly approximating natural seeding is to be preferred. As the grove develops thinnings, such as have been described of natural stands, are in order.
There is no reason why another species might not be interplanted with the maple to be cut at the end of twenty or twenty-five years for use as posts or Christmas trees. European larch, black locust, or spruce, depending on the soil, site, and ultimate purpose of the crop, might be used to advantage, although the writers have no records of such experiments in New York State.
Yield of Sirup per Acre of Grove
It has already been brought out that few groves in New York average more than 35 trees per acre of a size suitable for tapping, though under proper forest management this number might well be increased to 50.
On the basis of 35 trees per acre, using the average yield per tree of 2 ½ pounds of sugar, the sugar bush will produce from 85 to90 pounds of sugar per acre, or 11 gallons of sirup a year.
It is usual, however, to consider the yield per tree rather than per acre. A 100- tree sugar bush would yield 250 pounds of sugar or 30 gallons of sirup.
Manufacture of Maple Sirup and Sugar
The following is a list of the more important articles of complete sugar-making equipment, with a few notes on the size of the operation for which each is adapted:
- Tapping bit, 3/8 inch in diameter.
- Reamer, 7/16 inch in diameter
- Brace or auger with which to operate the bit and reamer.
- Light axe or hatchet.
- Claw hammer or a similar tool for removing spouts.
- Spouts or spiles.
- Buckets, 12-, 13-, or 16-quart capacity.
- Bucket covers.
- Gathering pails (in pairs), 16- or 18-quart capacity.
- Gathering tank, 3-, 4-, and 5-barrel capacity.
- Storage tank, from 8- to 20-barrel capacity and more.
- Evaporator house.
- Evaporator and arch.
- Cheesecloth or light flannel strainer.
- Sugaring-off arch and pan.
- Settling can, from 15- to 100-gallon capacity.
- Cans, pails, boxes, sugar molds, or barrels, in which to care for and dispose of the finished product.
Tapping bit – A short, stout, oval-lipped bit with a short, coarse-threaded, sharp screw which will cut rapidly and smoothly is recommended. Such a bit need not be more than 3/8 inch in diameter, which will permit the use of a 7/16 inch reamer. Any strong brace will serve, provided it holds the bit straight in the socket and firm.
Reamer – When the run is interrupted by a period of warm weather, the sap flow is slow and bacterial growth develops in the tap hole, resulting in sour sap and dark-colored sirup. Often this may be corrected by cleaning out the tap holes with a reamer, a special auger which bores a hole slightly larger than the previous one. By using a 3/8-inch auger to bore the original hole, the reamer need not be more than 7/16 inch. Hold the reamer firm and true so that it will make a round hole, otherwise leakage will result.
Sap spouts – The day of the wooden sap spout, made from a stem of elder with the pith pushed out, is past. The modern sugar maker demands a metal spout which is easily cleaned and will not corrode or rust. If it is made of iron, it should be galvanized or tinned. The part that goes into the tree should be round, smooth, and tapering so that it may fit bores of varying size. This will permit the same spout to be used after reaming. It should be strong enough to be driven with a mallet, yet capable of being easily pulled out at the end of the season. It should fit snugly into the hole without being driven so hard as to crush the wood cells or crack the bark. A snug fit at the collar of the spout is essential to prevent air from drying the walls of the hole and stopping the sap flow. A hook or notch should be provided on which to hang the bucket, for nails or spouts left in trees become overgrown and hidden in the wood, forming a source of annoyance and danger when the log is sawed into lumber.
Two types of spout seem to fill these needs. One is of cast iron coated to prevent rusting, with its shank deeply indented on four sides so that it touches few wood cells as it goes into the tree. Holes in the interior of the spout allow the sap to enter. A smooth collar fits firm against the wood, and a dam across the opening maintains a little reservoir of sap and keeps the air from reaching the wood. A hook provides a place to hang the sap bucket.
Another type of spout is made of sheet steel rolled to form an elongated funnel and coated to prevent rusting. The small end is closed except for a hole on the rear of the bore. A long, downward-curing under lip delivers the sap into the bucket without allowing any to flow backward on the underside of the spout. The makers of this spout claim that because of the long taper, it is not necessary to smooth the bark before boring the hole.
Buckets – Wooden buckets are fairly satisfactory, provided they are kept clean and painted each year, but metal buckets have largely taken their place. They are readily available, light, easy to clean, and will nest one in to the other, occupying comparatively little space during storage. The 12- or 13- quart size is satisfactory, and usually more convenient than the ones holding 16 quarts. Heavy tin plate is preferred to galvanized iron.
Bucket covers – Bucket covers are not necessary, but help to produce high-quality sirup and sugar. They keep out sticks and dirt, prevent snow or rain from dropping in, and keep the sap cool and sweet by shading it from the sun.
Some producers paint the two sides of the covers with contrasting colors, as white on one side and red on the other. By turning the covers each time that the buckets are emptied the gatherer makes sure that all of the buckets are visited. Experience of some large operators indicates that the close fitting cover is not satisfactory, as it excludes the air and the sap tends to sour.
Gathering pails – Gathering pails need to be larger than the sap buckets. The 18-quart size of galvanized iron or heavy tin plate is satisfactory. Special gathering pails are made large at the bottom to prevent tipping and spilling. Two for each man who expects to gather sap are needed. Occasionally these are carried on a yoke, but with a large gathering tank on runners this is seldom necessary.
Gathering tank – Gathering tanks are made in 3-, 4- and 5- barrel sizes. A 4-barrel tank is satisfactory for operations of from 500 to 1500 buckets. It may be mounted on a low sled or a stone boat and is equipped with a splash cover, a top strainer, and an outlet pipe.
Careful makers often supplement the metal strainer in the top of the gathering tank with a piece of cheesecloth, and let the sap flow thru another piece of cheesecloth when it is poured into the storage tank.
Storage tank – Metal storage tanks are made with a capacity of 8, 10, 15, and 20 barrels and over. The capacity of the tank should depend upon the extent to which the evaporator is capable of taking care of the sap flow. Allow at least one barrel of storage for each 50 buckets hung. This will take care of delays in evaporation and occasional heavy runs. The tank should be set on a strong frame and provided with a roof. It should not be in the evaporator house because the heat will encourage fermentation of the sap. The ideal place is on the north or east side of the house above the level of the evaporator, but no higher than the road so that sap from the gathering tank may flow directly into the storage tank and then on into the evaporator.
Piping systems – Labor difficulties have encouraged an increasing interest in schemes for piping the sap directly from the trees to the storage tank and thence to the evaporator. There is available a patented system of sectional metal pipes, each supported on wires and connected by a “goose neck” pipe to the sap spout. The sections of metal pipes are available in different sizes so that the diameter may be increased according to the number of trees which feed into it. The plan has some real merit for groves standing on a slope with the evaporator house conveniently located near the base.
Two outstanding difficulties prevent its general acceptance, (1) the time required to erect the pipes and (2) the difficulty of thoroughly cleaning them.
The advantages are chiefly the saving of labor and the direct delivery of the sap from the tree to the evaporator.
Evaporator house – The evaporator house should be located near the trees that are to be tapped, and near a supply of pure cold water. Comparatively short hauls from the trees to the evaporator house will help to hold down the cost of man and team labor. A house on a slope will make possible a raised driveway on the uphill side. This will permit the gathering tank to be emptied thru the outlet pipe directly into the storage tank, which should be above the level of the evaporator and outside the house, but under cover to keep the sap cool. The sap should flow directly into the evaporator. By taking advantage of the slope, the finished product can be loaded from the downhill side of the house. An ample supply of pure water is essential if the evaporator, the pails, and the other utensils are to be kept clean. Cleanliness in the entire operation cannot be too strongly stressed.
Sugar makers spend many hours over the evaporator, often working late in to the night. In spite of long hours and harsh weather, many producers think that any shack will do. Sometimes they seem to take pride in having it as rough as possible. Even though the man cares little for his own comfort, if he is to evaporate efficiently and protect the apparatus during the long idle months between seasons, the house should be well built, with tight sides, and should stand on a good foundation. The floor may be of concrete or wood, but the part in front of the fire box should be of concrete or brick to prevent any possibility of fire from falling embers. A wooden floor or platform, 8 or 10 inches high, along the working side of the evaporator is helpful. There should be several windows, for no one can work well in the dark. Doors should be at least 40 inches wide, so that one may carry an armful of wood through them. There should be room to work around the evaporator, space for a work bench, and possibly for a sugaring-off arch.
A brick chimney is more economical than a metal one because it does not rust. The chimney should extend well above the building to insure a good draft, but not so high that the fire will roar and waste fuel. Some makers of equipment recommend that the chimney be as high as the evaporator arch is long. A good fire, a cool chimney, and the use of a boiling pan indicate effective use of fuel.
Overhead, in the peak of the roof, extending the full length of the evaporator may be a ventilator with either side capable of being opened or closed from below. Driving winds can be kept out by closing the windward side. Cross drafts cool the sap and lengthen the boiling time, while good ventilation hastens evaporation.
One operator has developed a wooden hood which spreads out to cover the evaporator and carries the steam up through a funnel in the roof. This does away with the need of ventilators in the roof. The edge of the hood is about 2 feet above the top of the evaporator. A sectional canvas curtain hangs down from the hood to the outside of the evaporator, thus precluding any steam escaping into the room.
Adjoining the house should be space for storing a standard cord2 of fuel wood for every 60 or 70 trees tapped. This space should be roofed, but need not be sided. In smaller operations it is often found convenient to store wood in the evaporator house itself. If the steam is properly taken care of as described, there will be no excessive dampness in the wood so stored.
Sugaring-off room – It is more convenient to boil sirup to sugar over a separate fire, and preferably in a room separate from the sap evaporator. The higher temperatures require constant watching to prevent the sugar from burning on the bottom of the pan and to keep the sirup from boiling over the top of the pan. An ideal arrangement is to have the sugaring-off room adjoining the evaporation room. The inside dimensions of such a room should be at least 10 by 12 feet, which will accommodate the sugaring-off arch and pan, a work bench, and some storage space.
There are those who find difficulty in always boiling the sap to finished sirup on the evaporator. Frequently they carry the semi-sirup into the kitchen to finish the boiling on the kitchen range. This is usually inconvenient as well as wasteful. The sugaring-off outfit in the adjoining room serves equally well, and keeps the entire operation under one roof.
The sugaring–off arch is more simple than the evaporator and has pans which are shorter and deeper. They are usually from 2 to 2 ½ feet wide, from 3 to 6 feet long, and from 12 to 14 inches deep. A practical size for most farm operations is approximately 2 feet wide, 4 feet long, and 12 inches deep. The pan has a faucet for drawing off the thickened sirup and is set on an arch similar to that of the evaporator.
The sugaring-off room might be so arranged that the same brick chimney may be used for both the sugaring-off arch and the evaporator. If the pan is placed directly beneath two rafters or stringers, one man with the aid of a block and tackle can lift it from the arch and swing it to the work bench or to another part of the room where it is to be emptied.
Summary of the points of a good sugar house
- Tight walls which will exclude side draughts.
- Windows enough to insure plenty of light.
- Sufficient room for the evaporator and for operating it.
- A brick or concrete floor in front of the fire box.
- A raised plank floor by the working side of the evaporator.
- A woodshed at one end of the house large enough to store one full cord of wood for every 60 or 70 buckets hung.
- A ventilator in the roof, directly over and as long as the evaporator, adjustable from the floor.
- A room for sugaring-off.
- A work bench at one side of each room.
- A storage, outside of the building, on the shady side, easily accessible, and above the level of the evaporator.
Evaporator – The earliest evaporators are said to have been bark vessels, which held the sap and into which Indians dropped hot stones. These gave way to open kettles, and then to flat pans. Each is slow and produces an inferior product, for long boiling caramelizes the sugar and darkens the sirup. Modern evaporators are designed to reduce the sap to sirup or sugar with the least possible loss of time or wastage of fuel. Corrugations in the bottom of the pan give increased boiling surface and cleverly arranged partitions conduct the sap from one end of the evaporator to the other, keeping the thickening sirup separate from the sap. The flues and firebox have been perfected to a point comparable with the modern kitchen range or furnace.
Nearly all the evaporators in use by New York State farmers are made of sheet iron heavily coated with tin. No doubt some are of galvanized iron. One who wishes to make light-colored sirup should not boil sap in an uncoated iron pan, for the action of the iron on the sugar produces a dark sirup. The likelihood that the tin coating may wear off or the galvanized iron be corroded prompts the Bureau of Chemistry of the United States Department of Agriculture to recommend the use of copper.
Although a copper evaporator costs nearly twice as much as one of galvanized iron, the extra expense is more than counterbalanced by the advantages gained. Copper lasts much longer than galvanized iron; it can be easily cleaned without injury by the use of acid; it conducts heat better than does galvanized iron; and the use of a copper evaporator results in lighter-colored sirup. The first costs of a good evaporator is only a small item in the total cost of making sirup, so that the use of copper is in no sense of the word an extravagance.
The advantages of evaporators are: (1) rapid evaporation, which is essential in making light-colored sirup; (2) the sirup is concentrated in a thin layer, thus increasing the rate of boiling and foaming and affording better opportunity for thorough skimming; (3) heat is applied to the bottom of the evaporator, thus imparting an upward motion to the coagulated material, whereby skimming is facilitated.
Evaporating pans may be bought with the arch or furnace upon which they are intended to set. The fire box should be large enough to take 4-foot wood, or about 2 1/2 inches longer than the wood used. A well-distributed air supply is usually assured when there are numerous small grate flues. Dampers in the chimney regulate the draft. A well-constructed arch will allow the blaze to rise vertically, strike the evaporator close to the front end, and hug the bottom of the pan slightly beyond the arch of the chimney. To insure this the throat of the arch should be shallow, and fitted with dampers. The distribution of heat over the bottom of the pan may be further controlled by filling the base of the furnace with earth between the end of the grates and the chimney.
The ash pit should also be large, with doors which open wide to allow ample draft from below. Ashes should never be allowed to pile up close to the grates.
The arch may be supplemented by a casing of brick, but this is not necessary. In any case all exposed metal parts of the arch should be kept painted.
Manufacturers of sap-evaporating equipment are sometimes unduly optimistic regarding the evaporator capacity of their outfits. The estimates stated in most catalogs are high, so that the number of buckets that can be cared for may usually be cut in two if the producer desires to limit his boiling to the hours of daylight. In general, 1 square foot of corrugated bottom is capable of concentrating about 2 gallons of sap an hour, that is, a pan 3 by 8 feet, or 24 square feet, will evaporate from 40 to 50 gallons of sap an hour.
Only an unusually heavy run need keep the producer in the sugar house after sundown. This will help to adjust sugar making to the other farm operations. Furthermore, the quality of the sirup or sugar will be better because no sap will be left over from one day to the next. If more than 1000 trees are tapped, it is desirable to use two or more evaporators. It is then convenient to clean one every day and use the other for evaporating the first supply of sap in the morning. In case of an irregular run, labor troubles, or accidents to the equipment, such a plant is more flexible than one using a single large evaporator.
Fuel – The evaporator and arch already described is designed for fuel that may be burned in the fire box with the heat applied directly to the bottom of the evaporator pans. The most common is wood, although some farmers use soft coal. A few farmers in the southwestern counties use natural gas.
Wood – Wood is the most practical fuel to use in New York because transportation is eliminated. The material would often otherwise go to waste, and the odd time, always present during the season, can be used to advantage in cutting and storing the next year’s fuel supply.
For every 60 or 70 buckets hung there should be available, at the start of the season, one standard cord of well-seasoned wood. Green or wet wood is never satisfactory. To wait until the beginning of the season to collect wood, and to have to fall back on trash and green wood, is to cut down effective operation of the evaporator.
During a normal season one cord of fuel wood is burned in the making of from 100 to 120 pounds of sugar, or from 12 ½ to 15 gallons of sirup. No better use can be made of thinnings from the young grove or weed trees removed from the matured grove than for next season’s fuel supply. By doing this work at odd times, the cost is insignificant. An ungrazed properly managed sugar bush will supply sufficient fuel year after year to evaporate all the sap the grove will produce without decreasing its sap-producing power.
Steam – Theoretically, steam should be an ideal means of applying heat because the danger of burning the sirup is reduced to a minimum. Several New York operators have experienced considerable trouble with the boiler tubes which get coated and caked due to the character of available water.
Other evaporator equipment – Other equipment which is helpful in the manufacture of good sirup and sugar includes a thermometer, (supplemented if possible by a Baumé saccharimeter), a skimmer, at least two felt strainers, a settling tank, and possibly a set of sugar molds.
The standard thermometer for testing maple sirup and sugar reads to 260° F., and is usually marked off as follows: 219° F., sirup; 238°F., tub sugar; 245° F., cake sugar.
If much sugar is to be made, a sugaring-off arch to supplement the evaporator, will be found economical. As previously suggested, this should be in an adjoining room of the evaporator house. Some, who make only a small amount of sirup, often use a sugaring-off pan in which to furnish their sirup.
Cleanliness, speed, and regularity are three requisites to the manufacture of high-grade sirup or sugar. These must be applied to the entire operation if a light-colored, mild-flavored product is to be obtained.
Before the season, every utensil of the sugaring outfit, from spouts to evaporator pans, should be scrubbed and scalded. Roads should be broken thru the sugar bush so that the trees can be reached with the least walking between sled and bucket. The wood supply should be stored conveniently and ready for the rush. Containers for the expected crop should have been ordered during the winter and should be in readiness. An estimate of the number required can be made on the basis of about 2 pounds of sugar for each bucket hung.
Tapping Trees and Gathering Sap
Size of trees suitable for tapping – Trees less than 9 or 10 inches in diameter at breast height are not worth tapping. Such small trees do not have enough leaves to provide a satisfactory amount of sugar in the sap. Trees more than 12 inches in diameter at breast height may have two tap holes with as many buckets, and will yield more than twice as much sap as when only one hole is made. To put a third tap hole in trees ranging up to 20 inches in diameter does not materially increase the yield. Trees larger than 20 inches in diameter can usually carry three buckets, and very large trees four buckets. To hang more buckets on each tree seldom produces enough extra sap to warrant the extra expenditure. Furthermore, each tap hole increases the possibility of decay. The practice of tapping the tree in two places close together in order to collect the sap from the two in one bucket is not recommended.
Effect of tapping upon the tree – A maple tree which has been properly tapped is not seriously injured. The small amount of sap taken is scarcely more than from 4 to 9 per cent and can be easily spared. The chief danger to guard against is infection by wood-destroying fungi from which decay develops. A fair degree of protection is possible if the trees are growing vigorously so that the healing process is relatively rapid. Occasionally producers express a desire to plug up the old hole. This is possible, but, if a plug is used, it should not protrude beyond the growing tissues of the tree or it will obstruct healing. A hole made with a 3/8-inch bit usually heals in two or three years. For this reason, the use of plugs is discouraged.
Years ago when holes 1 inch in diameter were made, it was advisable to plug them to hasten healing.
The healed-over holes in a sugar maple ruin the “butt cut” for lumber production, but, unless decay has entered, the logs 5 feet above the ground are unharmed. Sawmill men usually avoid maple butts because of the danger of sawing into metal spiles which may have been left in the tree.
The flow of sap – Why does the sap of maple flow from places where the tree is wounded? It is scarcely necessary to go into all of the reasons which may be back of this, but certainly pressure is exerted which forces out the sap. During a few hours the pressure will rise, then gradually fall, and finally change into suction. For example, careful experiments have shown at eight o’clock in the morning a suction of 2 pounds to the square inch at the tap hole. At ten o’clock this may be pressure of 20 pounds, and by noon a state of equilibrium, displaying neither pressure nor suction, may be established. This slow pump like action or alternate pressure and suction is repeated day after day.
The daily range of temperatures during the sugar-making season has much to do with the yield of sap. Alternate freezing and thawing caused by cold nights and warm bright days, usually brings about a big yield of sap. If this condition continues for a total of four weeks during the sugar season, the year will be a good one for sugar makers. Continued warm weather will stop the flow of sap. This is also true of a high, drying wind. Sometimes a snowstorm will bring back the proper conditions and restore the interrupted sap flow. Each period of sap flow is known as a “run.”
The thin walls of the tiny wood cells permit the passage of sap, but exclude the air. The tapping bit penetrates the cells, exposes a number of cell walls, and the hole serves as a reservoir to catch the sap passing into the surrounding cells. Nearly all of the sap is carried in the layers of sap wood immediately under the bark, so that little, if any, sap is obtained from the deeper layers of heart wood.
The greatest flow of sap is during the early mornings. Records show that 60 per cent of the flow is during this period and ordinarily it slackens considerably by noon.
Tapping and bucket hanging – Sap will flow any time after the first thaw following the fall of leaves in the autumn. Tapping may continue from then on until the buds begin to swell in the spring. Usually March and April are the best sugar-making months, but occasionally a good run is obtained in February. The tapping should be done early enough to catch the first real run of sap, but not a day earlier as every hour tends to dry up the tap hole and to decrease the amount and the quality of the sap flow. The judgment of old sugar makers in the neighborhood will help the inexperienced man to decide when to tap his trees.
Select a spot for the new tap hole about 4 feet from the ground, at least 10 inches away from the nearest visible tapping scar, and where the bucket may hang plumb from the spout. Trees tapped approximately 4 feet from the ground yield a larger quantity of good-quality sap than do those tapped at the ground level or high up in the tree. If the bark is very rough; smooth it with a sharp axe, but ordinarily this is not necessary or desirable. With a sharp 3/8-inch bit bore a smooth hole slightly upward to allow draining and not more than from 1 ½ to 2 inches deep. Blow out the shavings and drive the spout in at once. Use a wooden mallet and do not drive hard enough to split the bark, for this allows the sap to leak, and permits the air to enter and dry out the hole. If not driven hard enough, the spout may pull out under the strain of a full pail.
Hang the buckets at once so as to catch the first run of the season. Many makers think this first sap is the best. This is probably because the utensils are clean and cool weather holds back the growth of bacteria so that a good product is more easily made.
Gathering the sap – Every bucket in the orchard should be emptied at least once a day. A single quart of stale sap mixed with a gathering tank full of perfectly fresh sap will contaminate the whole lot. When the trees are running freely, collect the sap twice a day. This is especially important during warm weather, for then the sap will sour quickly.
The buckets should never be carried away from the tree, but they should be emptied directly into the gathering pails. These in turn are carried to the gathering tank. A fine-meshed strainer over the mouth of the gathering tank will keep out leaves, twigs, and dirt. All sap should be hauled to the storage tank, outside the boiling house, and allowed to run thru the evaporator as rapidly as possible.
Ice that forms in a bucket of sap should not be thrown away as it contains enough sugar to make it worth while. It may be left in the buckets until it melts or it may be carried to the gathering tank. In either case it helps to keep the sap cool. Ice seldom forms when the buckets are emptied in the afternoon, as more than 60 per cent of the sap flow is during the morning. For that reason early afternoon is an efficient time to take it to the evaporator. If the run continues, another collecting tour may be made in the early morning or, in case of extremely cold weather, just before night.
The sap flow is never continuous, but is broken into several runs during the season. Between every run the buckets, gathering tank, and storage tank should all be washed, scalded, and, if possible, exposed to the sun. At least once during the season, and oftener if the sugaring time is prolonged, the tap hole should be reamed or a new hole made and each spout washed and scalded.
“Buddy sap” – The term “buddy sap” is usually applied to late runs, especially those occurring about the time the buds begin to burst. It may be green or yellowish, and has a peculiar odor. In contrast to this the sap at the beginning of the season is water white, clear, and transparent. It has a sweet taste and practically no odor.
Sap is very susceptible to the growth of bacteria. Their action is largely responsible for the souring of sap and the physical change which takes place toward the end of the season. When sap is running strong, the danger of souring is not great, but, when warm weather comes and the flow is intermittent, the bacteria become active. One of the first visible signs of sour sap is a mucous formation in the buckets. When this appears, the buckets and spouts should be cleaned thoroughly and scalded. If another run follows, the tap hole should be reamed out or a new one bored.
Much so called “buddy sap” results from lack of cleanliness, and does not always accompany the swelling of the buds. In fact, it may occur some time before the buds swell. It is largely caused by bacterial growth in the sap after it leaves the tree. Bacteria develop more rapidly during warm weather so that additional care is needed as the season advances. If all the utensils are frequently washed, scraped, and scalded, if the tap holes are reamed out or changed with each new run, and if each day’s sap is evaporated before the close of the day, “buddy sap” can be avoided until late in the season.
Starting the evaporator
Like the spouts and buckets, the evaporator must be thoroughly clean before the operation is started. This may be done by boiling water in the evaporator and scrubbing. Heavily tinned or copper evaporators may be cleaned by filling with a weak solution of hydrochloric (muriatic) acid and allowing it to stand for an hour or two. Galvanized iron is badly corroded by the acid and should not be treated in this way. The weak acid partially dissolves the sediment so that it may be scrubbed off while running water thru the pan. The pan must be well rinsed before filling it with sap.
Before starting the fire see that the intake from the storage tank is in adjustment, and flowing freely. If the pans are connected by siphons, they must be working and the bottoms of the pans must be covered with sap from 1 to 1 ½ inches deep. More than this prolongs the period of concentration and makes the product dark. As it boils, the sap in the sirup end of the pan should be dipped back to the inflow end until sirup of the desired density is flowing into the outlet. In the meantime, the scum which will constantly rise should be removed with a skimmer. This may be saved as a basis for cider vinegar. It should never be thrown carelessly about the place. Every effort should be made to keep the house and the surroundings clean and free from foul smells.
As the sap boils down to sirup, keep it flowing as steadily as possible from one compartment to another. After the operation is well started dipping should be avoided, for mixing high- and low-density sirup causes the finished product to be cloudy.
At the end of each day the evaporator should be cooled and held partly full of juice or water overnight. This can be done by flooding the pan with sap while the fire is hot, taking care that the pans do not boil dry. Skim the surface of the sirup before leaving it overnight. In the morning the bottom of the pan will be covered with a deposit. Unless this is scraped and the sap is stirred before building the fire, the heat will cause the deposit to stick to the bottom of the evaporator and a dark, poor-flavored sirup will result. Part of the sediment may be skimmed as it rises during boiling and the remainder will run out with the first few gallons of sirup.
Each morning the evaporator will have to be started with care to keep the pan from burning dry and to insure a constant flow from the sap intake to the outlet where the finished sirup is drawn off. To produce a clean bright sirup, the evaporator should be cleaned every two or three days, depending upon the quantity of sediment. Care must be taken to keep the pans clean, for dirty pans are responsible for much low-grade sirup.
Testing the density of sirup
Sirup should be as thick as possible without crystallizing or granulating. To meet these requirements the weight should be about 11 pounds to the gallon, although it is better for table use if boiled down to 11 ¼ or even 11 ½ pounds to the gallon. Such sirup contains about 35 per cent water.
Experienced operators are able to judge the density of the sirup fairly accurately while it is still boiling. Some do this by dipping the skimmer into the boiling sirup, holding it up, and noting how the cooling sirup “flakes off.” No amount of experience can take the place of accurate knowledge, and the uncertainties of guessing the density by the “flaking-off” method can be eliminated by using a thermometer.
It is well to check the accuracy of the thermometer by placing it in boiling water and noting the boiling point. An accurate thermometer should register 212° F. for water boiling at sea level. Roughly speaking, the temperature is lowered 1° F. for each 500 feet above sea level. Finished sirup weighing 11 pounds to the gallon boils at 219° F, or 7 degrees above that of boiling water. Sirup weighing 11 pounds 2 ½ ounces (11.15 pounds) will boil at 219.2° F. At 500 feet above sea level sirup will boil at 218° F., and at 1000 feet above sea level the boiling temperature will be about 217° F.
Thermometers should be kept clean because a coating of scum or “sugar sand” makes the reading inaccurate. Furthermore, the thermometer must not touch the bottom or the sides of the pan, but should measure the temperature of the liquid only.
The hydrometer, or Baumé saccharimeter, is often recommended, but is more troublesome than a thermometer. It is necessary to draw off a cylinder full of sirup from the evaporator and float the hydrometer in it. The Baumé reading for 11-pound sirup is 35.6°, and for a sirup weighing 11.15 pounds the reading is 37.1°. Baumé test should be used in sirup of approximately 60° F., as higher temperatures destroy its accuracy.
Sirup which contains more than 35 per cent water is likely to ferment and sour, while that which contains less than 32 per cent may form crystals. For that reason sirup weighing between 11 and 11 ¼ pounds to the gallon is the most satisfactory.
Some makers cleanse the sirup with white of egg, milk, cream, or even small quantities of cold sap. When these are thrown into the boiling sap, violent bubbling follows which throws impurities to the surface where they may be skimmed off. There is a difference of opinion concerning the use of cleaning substances, but as similar results are accomplished by allowing the finished sirup to stand in a settling tank for twenty-four hours, their introduction is not recommended. It is true, however, that good sirup can be made by either method.
Hot sirup will pass thru cloth strainers in a reasonable time, but the Bureau of Chemistry declares that this does not remove much of the sediment. When it has cooled to atmospheric temperature, the sirup at final density cannot be efficiently filtered by any means. For this reason the settling tank is recommended.
Sediment includes malate of lime or “nitre” which is present in all sirup. The amount varies, depending as much upon the soil where the trees grow as upon the skill of the operator. Sirup that has been allowed to stand and settle for from twelve to twenty-four hours is reasonably free from sediment. Special settling tanks with the outlet from 2 to 3 inches above the bottom are available. If these are used, it is not necessary to strain the sirup thru felt. Sirup which has settled overnight should be reheated before pouring it into cans.
In the making of sirup too much emphasis cannot be given to cleanliness. The evaporator, the tanks, the buckets, and the spouts must be free from sediment and scale. There should be plenty of pure water so that all equipment may be washed as often as necessary. Equipment that has stood idle for several days should be washed with strong lime water, which neutralizes acids and helps to prevent fermentation. After using lime, all the equipment should be carefully washed again.
Most careful makers boil the sirup to final density in the evaporator, while others take it off before it is complete and finish the boiling in the sugaring-off pan or on the kitchen range. They claim that this increases the capacity of the evaporator and allows the hot sirup to be twice strained before it is poured directly into the cans. Modern evaporators are designed to complete the boiling from sap to sirup in one operation, for each reheating darkens the sirup. The labor and the muss of transferring the unfinished sirup from the evaporator house to the kitchen, the unavoidable loss in transit, and the fact that rapid, continuous boiling gives the best product, all point to the advantages of finishing the boiling in the evaporator or in a sugaring-off pan near where the sap is received.
Sirup that has been reduced to the desired density is ready for canning after it has been strained or settled. Some sugar makers pour the sirup into cans while it is hot; others prefer to let it cool. Hot sirup poured into a can will shrink as it cools and will create a vacuum. If this vacuum is too great, “buckling” results. On the other hand, cold sirup may expand in the can and be forced out from under the stopper, or it may even burst the seams of the can. Cold-canned sirup is more likely to be attacked by mold-forming bacteria than that which is canned hot.
The Bureau of Chemistry recommends that sirup be 180° F. when poured into gallon cans while temperatures as low as 160° F. are satisfactory for the large drums or steel barrels. Higher temperatures darken the sirup. As it cools, a vacuum may be created sufficient to cause the cans to “buckle.”
Assuming that the cans or drums are clean and tight, at least three conditions are necessary to prevent loss:
- Fill with sirup at the proper temperature (180° F. for gallon cans; 160° F. for drums).
- Close the caps air tight.
- Do not keep the sirup hot longer than necessary, either before or after canning.
Tip the metal cans slightly as they are being filled, then lift by the upper edges and fill even with the screw top before it is screwed tight with a wrench.
When filling cans with cold sirup, compress the sides a little, fill to the top, and screw on the lid. This allows for an increase in volume when the lids become warm. The method of canning in use by C.B. Wieland of Virgil, New York, is as follows: Strain the sirup while hot and leave it in the settling can for twenty-four hours. Fill the can up to the neck and allow the sirup to stand thirty minutes. Then fill the can to the top of the screw. Place a piece of wax paper the size of the cork in the screw top. Screw the top on and tighten it with a wrench. If the top is air tight, no mold will form. In case mold does form, it can be lifted out with a teaspoon handle when the can is opened for use. Sirup canned by this method has been kept for ten years.
Sirup should be stored in a dry, cool place. Whenever the cans are piled in stacks, place narrow strips of wood across every three or four rows to permit the circulation of air and encourage cooling. A cool, dry cellar is best for storing sirup. Well-made, properly canned sirup will keep from one season to another without souring or bursting the container.
A small evaporator or special pan may be used for sugaring-off, or boiling the sirup into sugar. The most convenient place for this is the evaporator house, and, if much sugar is to be made, a special room is recommended. Many farmers wish to avoid this extra investment and boil down the sirup on the kitchen stove. This is wasteful and inconvenient and should be discouraged.
To make soft or tub sugar boil the sirup until the thermometer registers from 26 to 28 degrees above the temperature of boiling water (from 238° F. to 240° F. at sea level). Skim with the same care as when making sirup. Foaming can be partially controlled by running a small piece of butter, lard, fat meat, or even a little sweet oil over the surface. This fat must be without flavor, or it will spoil the sugar. In any case it should be used sparingly.
If the boiling continues until the thermometer registers from 30 to 33 degrees above the temperature of boiling water, the product will be hard or cake sugar. This contains les moisture than soft sugar, and is more subject to burning. Commercial plants reduce the sirup to sugar with steam and thus avoid the danger of burning.
Failure to sugar-off each charge before adding more sirup for concentration prolongs the boiling, and results in a dark product. Furthermore, it causes slight decomposition so that hard sugar is difficult to make. From 1 to 10 gallons can be sugared-off at one charge, depending upon the size of the equipment.
Both hard and soft sugars may be poured into molds. The cakes may range in size from those made for the confectioner to big bricks of 10 or 20 pounds. Hard sugar that is stirred while it cools resembles ordinary brown sugar, but retains the maple flavor. This is usually made for home use or local sale.
Tub sugar need not be of inferior quality, but it often is. Poor sirup which will not harden is sometimes used so that a molasses-colored liquid rises to the top of the tub leaving the rest of the contents mushy.
So much interest has been shown in maple cream that the following directions from the Bureau of Chemistry, United States Department of Agriculture, are included.
Maple cream is a high-quality product which appeals strongly to the palate of the public. The market for this article has great possibilities, if properly developed. Being a high-grade product, it is essential that quality be maintained and that the finest article attainable be produced.
Important marks of quality in maple cream are very smooth texture and consistency; in other words, it should not feel coarse or “sandy” to the tongue. Upon standing, no sirup should come out and separate at the surface. Maple cream consists of exceedingly small crystals of sugar which are too small to be seen by the naked eye, but can be observed easily under a microscope. These crystals are surrounded and separated from one another by thin films of sirup. The art of making fine maple cream depends primarily on keeping these crystals so small that they cannot be detected by the tongue; otherwise, the cream has a coarse or gritty feel. Also, if the crystals are small enough they will retain the sirup better, so that it will not come out readily and separate at the surface on standing.
The making of fine maple cream is really part of the candy maker’s art and is similar in practically all respects to the making of the cream or fondant used in the familiar chocolate-coated creams. If carefully observed the following directions, which have been adapted from the art of candy making, will insure the consistent production of smooth maple cream of high quality. It is strongly urged that a thermometer, preferably a home candy maker’s thermometer, be used.
Boil the batch of maple sirup briskly to about 232° F. Keep the sides of the kettle free from sugar crystals by wiping with a wet cloth or brush. Pour the sirup into clean shallow pans (roasting or baking pans). The layer of sirup should not be over ¾ inch deep. In order to avoid premature formation of sugar crystals, the cooked sirup should be cooled quickly with as little movement or agitation as possible.
The pans of sirup may be placed outdoors to cool or, if cooled indoors, they may be cooled quickly by placing in a large pan containing snow or cold water. The sirup should cool to about 70° F. (about room temperature) before “creaming” is commenced. This can easily be determined by testing with the hand after the sirup is brought indoors (in case it was placed outdoors to cool). These precautions make it possible to keep crystallization (creaming) under control and to produce the size of crystals and consistency desired.
Hard wooden paddles with a somewhat sharp edge and about two to three inches wide will be found very efficient for “creaming.” The pan is held or fastened on a table and the batch is scraped with the paddle to one side of the pan and then back again, thereby mixing the batch so that no portion is allowed to remain at rest. This thorough mixing causes crystallization to start and at the same time prevents the sugar crystals from growing too large. If the agitation of the batch is stopped or interrupted the crystals will grow rapidly, resulting in a “sandy’ or coarse consistency, especially if the temperature is a little too high.
This stirring and scraping is continued until the batch becomes somewhat stiff and shows a distinct tendency to set’ that is, the furrows made by the paddle do not close up rapidly. This stiffness is caused by the formation of great numbers of microscopic sugar crystals. The finished cream can be poured directly into the final packages if desired, but care should be taken to continue stirring and not to commence pouring until the batch is barely fluid enough to run. If the cream is too fluid when poured, more sugar crystals will be formed after pouring and these may be so large as to cause “sandiness.” If desired stirring can be continued until the batch becomes stiff. The finished batch may be packed in glass or earthenware containers and tightly covered; it can then be “remelted” at leisure and poured into suitable packages. Remelting is done by heating the cream in a double boiler and stirring until it becomes just fluid enough to pour. Don’t heat to any higher temperature than necessary. It can then be poured without much danger of forming air pockets which detract from its appearance in a glass container.
How to shorten the time required for creaming
The creaming operation can be considerably shortened, with the assurance of producing a smooth area, by incorporating in the batch a small proportion of “inverted” maple sirup. The nature of “inverted” maple sirup and the manner of preparing it are described below.
Bring the maple sirup to a brisk boil and then add the required amount of “inverted” maple sirup. Cook to a temperature of 232° F. The usual proportion of “inverted” maple sirup is 1 pint to each 6 gallons of ordinary maple sirup in the batch. Pour the cooked sirup into pans as already described and start “creaming” as soon as the temperature drops to about 100° F. ( instead of 70° F. as above). The temperature should be determined by a thermometer (preferably a candy maker’s thermometer), tilting the pan, if necessary, until the sirup is deep enough at one end to cover the thermometer bulb. Don’t stir the sirup more than absolutely necessary.
After “creaming” is commenced, if the stirring and scraping are continued without interruption, a smooth cream will be obtained in a shorter time than when the sirup is cooled to 70° F. However, if the “creaming is started at 100° F. without adding some “inverted” maple sirup, there is great danger that the cream will be coarse or “sandy” in texture.
Preparation of “inverted” maple sirup
The chemical name for the sugar in maple sirup is “sucrose.” This sugar consists of two simpler sugars, dextrose and fructrose, united together. A mixture of these two sugars in equal proportion is called “invert sugar.” Invert sugar is the sugar present in honey. It has the property of preventing crystals of sucrose from becoming very large; hence, the advantage of adding a little “inverted” maple sirup in preparing maple cream. In “inverted” maple sirup the sucrose has been split up into invert sugar. Sucrose can be converted into invert sugar through the action of a substance called invertase, which is used in an extremely small amount for this purpose. Two methods of preparing “inverted” maple sirup are described:
Cold or slow method – This is best method. It requires more time, but is much simpler than the warm, or rapid, method described below. All that is necessary is to add 2 ½ fluid ounces of invertase to each gallon of maple sirup, stir thoroughly, and allow to stand at about room temperature (65 to 70° F.) for 10 days (a somewhat higher temperature will do no harm). At the end of this time the sirup will be ready to use and should be added in the proportion mentioned above in making maple cream.
A small glass cylinder or bottle graduated in fluid ounces, which may be bought at any drug store, is convenient for measuring the invertase. Many medicine bottles are graduated in fluid ounces.
Warm or rapid method – Two and one-half fluid ounces of invertase, as above, is added to each gallon of maple sirup and is thoroughly mixed. The sirup is then placed in a well-tinned metal pail with a cover or in glass Mason jars. The containers are placed upon a rack fitted into an ordinary wash boiler, similar to the arrangement for cold-pack canning. Water is poured into the boiler until its level is just below the top of the pail or glass jar. The boiler is heated on the stove until the temperature of the water reaches 130° to 140° F. It is important that the temperature of the sirup never exceeds 140° F. The invertase loses its activity at a temperature much above this.
After the water reaches the proper temperature, the boiler should be moved to a cooler part of the stove in a position to keep the temperature at about 130° to 140° F. (but not above). When the fire becomes low or is allowed to go out at night, the boiler should be well covered with blankets or similar wrapping so as to retain the heat during the night. Under these conditions the preparation of the “inverted” maple sirup requires about 24 hours. It is best to start the batch in the morning; it will then be finished the next morning.
A fireless cooker is very convenient for preparing “inverted” maple sirup by this method. After adding the invertase, simply heat the maple sirup to 140° F. (not above), place immediately in the fireless cooker, and allow it to remain for 24 hours. (Use no stones.)
In both the slow and rapid methods the addition of invertase may modify somewhat the flavor of the “inverted” maple sirup added.
The stock supply of inverted maple sirup may be kept at any temperature below room temperature if desired.
Precautions and comments
A smaller proportion of “inverted” maple sirup should usually be added to maple sirup from the later runs of the season. In some cases when late run sirup is used no “inverted” maple sirup may be needed, even when “creaming is started at 100° F. The proportion of 1 pint of “inverted” maple sirup to 6 gallons of ordinary maple sirup may be varied when necessary. The general rule to follow is that when the directions given in this circular are closely observed and the cream is “sandy” or coarse in consistency, the proportion of “inverted” maple sirup should be increased somewhat and when the time required for “creaming” is excessive the proportion of “inverted” maple sirup should be reduced.
The pans and paddles should be thoroughly washed between batches to remove all adhering portions of cream; otherwise, small particles of cream may start the formation of sugar crystals prematurely in the next batch, thus producing crystals that are too big and causing “sandy” consistency.
In order to produce smooth cream it is important, after “creaming” is commenced, that the batch be kept constantly stirred until crystallization is practically complete, as shown by the stiffness of the batch. Sugar crystals which are formed while the batch is at rest are considerably larger. Therefore, if many sugar crystals are formed after stirring is discontinued, they may be numerous and large enough to cause “sandiness.”
Precautions to avoid keeping the maple cream at too high temperature after packing will reduce the separation of sirup at the surface on standing.
When maple cream is made on a sufficiently large scale, it may be advisable to use the smaller mechanical beaters rather than hand labor for “creaming.”
Maple cream forms the base for the manufacture of a wide variety of dainty confections. If one has attractive molds available, it is well worth one’s time to make up pure maple cream or fudge in different shapes and sell in dainty packages. Nuts may also be added, either chopped or in halves on top of the molds. Many maple-sugar producers in New England have found it profitable to cater to the tourist trade by direct sales at roadside booths to those traveling by automobile, or to build up a mail-order business thru advertising. While sirup is often sold, as well as sugar, this business rests essentially on maple sugar in the form of high grade confectionery.
Packages for Sirup and Sugar
Sirup and sugar are put up in packages as various as can be suggested by the minds of the makers. Pails, both wood and tin, boxes of all sizes, tins, glass (from gallon jugs to tiny glasses), waxed paper, brown paper cartons, dainty confectionery boxes, and so forth, all are used.
Farmers who prepare sirup for local trade or home consumption usually pack it in rectangular tin cans with a screw cap. The one-gallon size is most popular with producers; a few use half-gallon tins, and others pack in quart jars.
The principal advantages of the rectangular tin can are comparative cheapness, ease of filling, convenience of packing for shipment, and availability. These are largely offset by unattractive appearance and the demands of housekeepers and distributers for smaller containers. The gallon can is too large for the majority of city consumers and small stores. This has been recognized by the large distributers of sirup who are now selling most of their product in quart, pint, and even half-pint containers.
About 40 per cent of New York State’s sirup is packed in steel drums holding from 30 to 55 gallons. These are usually furnished by the large canners or processors and more recently by the farmers’ cooperative association. Steel drums have largely displaced the wooden barrel because they are more easily cleaned, can be used for several years, and are more convenient for shipping and storing.
Maple-sirup makers who cater to a private trade will appreciate the following recipe for a paste which will cause paper labels to stick on tin cans: One-half ounce of silicate of soda (water glass), 1 ounce of cornstarch, 1 ½ pints of cold water. Add the starch and the silicate to the water and stir until the whole is smooth, then place the vessel in a double boiler and heat until the starch is gelatinized. This paste should be made often as it soon loses its sticking properties.
Maple-sirup skimmings, dark or slightly scorched sirup, and maple sap or sirup which has begun to ferment can be made into excellent vinegar.
The following formula is suggested:
- Maple sirup diluted with soft water to weigh 9 pounds to the gallon, 30 gallons.
- Ammonium sulphate, 2 ounces
- Sodium phosphate, 2 ounces
Dissolve the chemicals in the water before diluting the sirup to assure their complete solution in the sugary liquid. They are added because diluted maple sirup lacks sufficient nitrogen and phosphorus to provide food for the vinegar-making bacteria.
Maple sirup which has been diluted so that it weighs 9 pounds to the gallon will contain from 12 to 15 per cent sugar, as compared with 35 per cent sugar in sirup weighing 11 pounds to the gallon. This can be tested with the Baumé hydrometer.
If kept moderately cool (about 50° F.) alcoholic fermentation will probably take place spontaneously in the barrel. Fermentation can be made certain by putting in a cake or two of compressed yeast.
Alcoholic fermentation will be completed in about two weeks, after which the liquor should be carefully strained into a vinegar barrel. Add a small quantity of “mother of vinegar” or old vinegar to the extent of about one-tenth the volume of the alcoholic liquid. “Mother of vinegar” is the slimy skin which forms on the surface of vinegar. It is the growth of bacteria which convert alcohol into ascetic acid, which is the characteristic acid of vinegar. Before pouring in the old vinegar, strain it thru cheesecloth, flannel, or felt to take out any vinegar eels or vinegar flies.
Warmth and air are necessary to produce vinegar. The room temperature should be about 70° F. and the half-full barrel may be laid on its side with both bung holes open. Vinegar flies may be excluded by covering the holes with muslin or cotton batting.
Between 25 and 30 gallons of vinegar can be made from materials that would ordinarily be thrown away in the course of operating a 1000-tree sugar bush.