NPR ran an article from NW News Network about the Big Leaf Maple, Bigleaf Maple Syrup Flows As Profits Drip From Once-Maligned Northwest Tree, on January 26, 2020. The following article appeared in Small Farmer’s Journal in 1983.
Syrup From Oregon’s Big Leaf Maple
by Victor Morejohn, photos by Tal Blankenship
There is a great potential in establishment of a seasonal “sugarbush” industry for small farmers of the northwestern states, particularly western Oregon and Washington.
Five syrup producing species of maples (Sugar, Black, Red, Silver, Box Elder) are found mainly east of the Rocky Mountains. These species overlap in geographic distribution from the southern Great Lakes region eastward. The Sugar Maple (Acre saccharum), often called hard rock maple, and the Black Maple (Acre nigrum) are considered the most important syrup producing species in the United States.
The Box Elder (Acre negundo) and the Big-leaf Maple (Acre macrophyllum) are the only syrup producing maples of the Pacific Northwest. Properly made syrup from these two western maples is indistinguishable from the syrup of maples of the midwestern and northeastern states.
When to Tap the Trees
Whether you live in the northeast, midwest or along the Pacific slope, the time to start tapping the trees may come anytime from mid-January to mid-March, whenever spring begins fingering into winter. In most areas of the northwest, January and February are the months to begin tapping. The time to tap maples for sap is on clear, warm days after a snowy, icy or frosty night, when the temperature drops below freezing. At this time of year, west of the Cascades in central and southern Oregon, weather conditions from year to year, however, are unreliable. We may have five to six weeks without frosts, overcast days or intermittent rains with night-time temperatures above freezing. If so, no maple syrup for that year. Or we may be blessed with clear, sunny days with above freezing daytime temperatures and crispy, frosted clear nights below freezing. This type of weather makes the sap flow.
I generally cut a branch tip off below a bud and watch it for a few minutes. If it begins to bleed sap, it is time to get your brace and 7/16″ wood bit and start drilling your holes. We have over fifty-five Big Leaf Maples along a 3/4 mile stretch of our farm along the South Umpqua River. I try to be selective and choose trees that are not too crowded with Ash or Cottonwood trees. I choose open-crowned trees that have not been reaching for sunlight under the larger Cottonwoods. These trees produce more leaves (have more chlorophyll) and consequently are capable of putting more sugar in their sap.
How to Tap Trees
Although it is recommended that holes be drilled on the southern side of maples for more sap flow, I have found that some trees located on southern exposed river banks, where I could only tap the north side, have yielded as much sap as trees of similar size tapped on their southern side.
Make the holes about waist high, three to four inches deep, slightly inclined upward into the tree; and clean out all shavings with a narrow, pointed knife. Once the hole is made, a conveyance is necessary to direct the sap into a container. Any type of cylindrical, hollow structure may be used, such as finger-sized, straight twigs that have pithy cores. These may be hollowed out and will do the job. Plastic or galvanized pipe also may be used. Commercially these things are called “spiles” (Figure 1) and are available in several styles relatively cheap ($.30 to $.75) and may be purchased from several midwestern or northeastern maple syrup and equipment and supply companies. Homemade spiles are not as efficient as the commercially manufactured types, mainly because plastic or galvanized pipe sections are not tapered. The commercial types are conical (tapered sides) for several reasons: the neck of the spile is larger in diameter (1/2″) than the bored hole (7/16″) and are hammered into the hole to make a snug fit at the neck of the spile (Figure 2). In this manner, the conical part of the spile in the hole does not touch the sides of the holes. Essentially the neck of the spile plugs the hole, preventing leakage, and sap can freely flow into the space around and in the spile tip. The metal nubbin above the spile spout serves to allow a claw hammer or small prybar to remove the spile for cleaning or for end-season removal. Plastic or galvanized pipe sections have parallel sides, fit tightly along the length of the hole, allow sap to enter only from the end within the hole, and are difficult to remove from the trees. Our neighbor, Ray Hicke, downriver from us, told me that when he was a youngster back in the Dakotas, he helped his Dad tap maples. For spiles, his Dad used old sickle bar teeth, slightly bent from tip to base to serve as spouts. He drove them point first into the trees below a drilled hole and used the rivet holes on the end of the base to wire on his containers.
Collecting the Sap
Any container may be used to collect the sap. Buckets especially made for the purpose are also available commercially. I have used any clean, metal container that I could get ahold of. The container may be fastened to the spile hook through a hole punched with a nail below the container rim, or a wire bail may be readily made and fastened to the container through two holes punched opposite each other below the rim (Figure 3). I prefer to use bails because the containers do not necessarily nest into each other as commercial bail-less ones do, and I can carry several empty ones in one hand by using their bails.
Depending on the size of the sap containers and the rate of sap flow for the day, you may have to visit your maples once or twice in the afternoon. Bring along large collecting buckets. We use three to five gallon plastic buckets with snap-on lids (Figure 4). If you have a lot of sap to collect, carrying these large buckets filled with sap can be hard on one’s shoulders, back or elbows. If you do not have a tractor, truck or team to bring in the daily sap, use a wooden yoke over your shoulders.
From Sap to Syrup
Once the sap has been brought in, syrup making can commence. All sap should be strained to remove debris and insects. We used milk filters. Strained sap may be boiled in any container, but to be efficient it is best to use a flat pan filled three to four inches in depth with sap. If done in the home kitchen, steam from the evaporating sap can be damaging to woodwork and painted surfaces in the immediate area.
One of the problems in making maple syrup outdoors on a small scale, is to be able to maintain a rolling boil in the syrup pan. If you use part of your barn, implement shed or wood shed, try to set up some form of protection from cold winds blowing on the stove (Figure 5). Be sure to keep all inflammables (hay, straw, oil, gas, etc.) away from the area where the sap is to be evaporated. On a larger scale, a “sugar shed” is constructed especially for this purpose.
As the sap boils, water is evaporated and the sugar concentration relative to the sap volume increases. The level of the boiling sap will drop slowly during evaporation and more sap will need to be added periodically. Too much cold sap added to the boiling pan will quell the boil. You have to learn to judge the correct amount to add for the size of the pan. We used a large turkey roaster pan. Allowing the fire to go to embers before more wood is added will also put down the boil. The sap should continually boil. We learned that by putting freshly gathered cold sap into large metal pots, pans or buckets on our wood stove inside the house, we could raise the temperature to near boiling, effect some evaporation and kill the yeasts and bacteria that sour sap if it sits around for a day or two during warm days.
Outside in our “sugar shed” we kept a large metal bucket warming next to the stove pipe of the log-wood stove we used for evaporation. We ladled hot sap from this bucket into the boiling syrup pan. Periodically we filled this bucket with the hot sap from the stove in the house. In this manner no cold sap was poured directly into the boiling syrup, and we had no difficulty maintaining a rolling boil.
Dependent upon your vigilance in maintaining a rolling boil, accomplished only by judicious care of the fire, the amount of firewood you will burn to produce a given quantity of syrup will approximate one cord of wood to about 25 gallons of syrup. Richard Lamore (in Thompson, Syrup Trees, 1978, p. 50) estimates one cord per 28 gallons of syrup.
It is difficult to determine the amount of time needed to evaporate a given amount of syrup to sap. There are many factors of the environment that bear upon this, such as air temperature, wind and of course the sugar content of the sap. On the average, midwestern and northeastern maple syrup producers evaporate 55 gallons of sap to produce one gallon of syrup. This figure is for the industry at large. The sugar content of individual trees may vary from as little as 1.5% to as high as 7%. The average is about 2.5%. Our Big-leaf maples have given us a ratio of 38 gallons of sap to one gallon of syrup. This is a higher yield than the sugar maple, but it is not surprising, since the Big-leaf maple has the greatest leaf area of all maples to use in photo-synthesis (making sugar from carbon dioxide and sunlight) and has a longer growing season in most northwestern regions, than midwestern and northeastern maples.
As the clear sap slowly evaporates to syrup, it will begin to take on a light brown color, and it will now readily boil up into foamy froth that must be controlled. It is critical at this stage to know when you do, in fact, have syrup. A candy thermometer will work very well. First determine the temperature at which water boils in your area. This will vary depending upon barometric pressure. It may boil at 209°F or at 212°F. Simply add 7°F to whatever temperature at which water boils in your area, and when the candy thermometer registers that summed temperature, you have syrup. Syrup that has been boiled beyond 219°F becomes dark brown and strong-flavored. Some home syrup makers judge when syrup is ready to bottle by the way it looks and runs. Bailey (in Small Farmer’s Journal, Fall, 1981, page 67) writes of the way syrup “aprons” off a ladle when ready to draw off (Figure 6).
Although the sap was filtered at the outset, the syrup now will have to be filtered again since different ingredients of the sap have crystallized into a sandy substance referred to in the trade as “sugar sand.” This will plug milk filters quickly, and it is best to use commercially available maple syrup filters, flannel or felt if one is to have clear syrup with nothing to settle in the bottom of the jar. We poured the boiling syrup into a metal bucket, brought it to the house to filter, and bottled it in sterilized pint jars. We then processed the filled pint jars in a steam canner as double insurance against spoilage. High quality syrup is amber colored and weighs 11 pounds to the gallon.
Maple syrup is a farm crop, whether made from sap of wild grown trees or maples planted as in an orchard. A paramount concern is for a long productive life for the tree. Maples are not pruned to increase production, but decay of the wood should be prevented in the region of the tree where holes were drilled. After sap ceases flowing for the season, all spiles should be removed and the holes disinfected with a 1 to 10 solution of Clorox. Use a plastic squirt bottle. The holes will heal by themselves within a couple of years. All equipment used should be thoroughly cleaned with a detergent solution, rinsed and put away dry.
Tools, Equipment and Supplies Needed
- Pruning shears
- 7/16″ wood bit
- Knife, tapered & pointed
- Spile driver
- Buckets or tin cans
- Wire for bails
- Candy thermometer
- Pliers with sidecutters
- 16d common wire nail or punch
- Large roaster pan with lid
- Log-burner stove
- Firewood, split 2″ x 3″, dry
- Plastic squirt bottle
- Chlorine bleach (1.10 water)
- Slotted spoon
- Flannel filters
- Canning jars & lids
Agricultural Extension Service, University of Minnesota. 1974. Information on how to collect maple syrup and make maple syrup. St. Paul, Minnesota.
Bailey, L. H. 1907. Maple sugar and maple syrup. Reprinted from Cyclopedia of American Agriculture in Small Farmer’s Journal, Fall, 1981, Vol. 5, No. 4: 64-67.
Domico, Terry 1979. We make sweet syrup from Pacific Northwest trees. Mother Earth News. No. 55 (Jan/Feb): 65.
Kappel-Smith, Diana 1982. Pipeline in the sugarbush. Country Journal, Vol. IX, No. 2 (Feb): 66-74.
Nearing, Helen & Scott, 1950. The Maple Sugar Book. Schocken Books, New York.
Nickerson, Nancy 1982. Box Elder syrup. Organic Gardening. Vol 29, No. 2 (Feb): 126-128.
Pieper, Ruth 1975. We make our own maple syntp. Organic Gardening and Farming. Vol. 22, No. 1 (Jan): 78-80.
Seymour, John 1976. The Guide to Self-Sufficiency. Popular Mechanics Books, New York.
Thompson, Bruce 1978. Syrup Trees. Walnut Press, PO Box 17210, Fountain Hills, AZ 85268.
U.S. Department of Agriculture 1965. Maple Syrup Producers Manual. Agriculture Handbook No. 134. Washington: Government Printing Office. Revised Ed.
Wilson, Barbara H. 1982. Tapping the Front Yard Maple. Organic Gardening. Vol. 29, No. 2 (Feb) 122-125.