Growing Sunflowers and Pressing Oil at Garden Scale

by Michael Cohen of NY

Background

I garden in Zone 5A in Upstate New York using organic methods with hand labor and a few battery electric tools. I no longer do any mass rotary tillage and only minimal shallow cultivation, primarily for planting. I grow mostly staples: tomatoes, garlic, small grains, dry beans. I also occasionally grow experimental crops: upland rice, flax for fiber, sesame for seeds, naked seeded pumpkin; and sunflower for seeds and oil.

Lately, adapting the practices of Masanobu Fukuoka and Helen Atthowe, I have been trying out gardening in a permanent living mulch. Ideally it would be a sort of locally adapted sod where complex biological systems thrive and help nourish the crops. My living mulch consists mostly of volunteer perennials: grasses, dandelion, plantain, Asiatic smartweed, chickweed, and my nemesis ground ivy. I do selective weeding of ground ivy (“Creeping Charlie”) because it forms thick mats that kill everything else.

Sunflower Oil

I want to produce the three principal ingredients for my sesame whole grain crackers: hard red winter wheat flour, sesame seeds and sunflower oil. The winter wheat I have been growing for years. In 2023, I grew sesame seeds and also worked on a new approach to making sunflower oil.

To make sunflower oil I needed a relatively low-tech and low-cost system scaled for human labor and small volume. The Piteba hand crank spiral press is a workable solution. In 2019 I grew Perodovic oilseed sunflowers. Piteba recommended pressing the small seeds whole with the shells still on, but it was too hard to press oil that way using human power. In 2023 I grew Mammoth, a large seeded snack or confection sunflower. My plan was to press oil from softer, dehulled nutmeats. This is how I did it:

1. Grow Sunflowers

Early May 2023

The 2022 tomato section was rotated in 2023 to a companion planting of field corn and sunflowers. During the first week of May I started preparing that section by setting back the ground ivy with flaming and a stirrup hoe. Then I laid out the rows 40” apart.

Prepare Strips in Living Mulch

I need a weed free, finely textured seedbed for direct seeding crops. During the second week in May I prepared planting strips in the living mulch about 10” wide and 5” deep. To break up the living mulch, I used first a high wheel cultivator with only two tines about 4” apart, and second a 9” x 5” stirrup on a Planet Junior wheel hoe. Several passes with each tool, raking out the roots in between, created a reasonably fine seedbed. Waste roots are saved for use as mulch. If left in the soil some will re-sprout.

Plant Sunflowers 5/19/23

I broadcast dry fertilizer onto the strips and mixed it into the soil with the two-tine high wheel cultivator. I use Krehers (5-4-3) pelletized chicken manure with 9% Calcium; feather meal; and some azomite on each strip.

I planted the sunflowers 1-2” deep with an Earthway seeder using the Okra plate with every other cup taped shut. I firmed the seedbed with my homemade push cultipacker, watered it in, and covered the newly planted rows with a light mulch.

I could have planted a week earlier, around 5/12, and then I could have harvested earlier in the fall.

I overplant so losses to critters are not fatal to the crop. I could try to protect the seeds and young plants with spun row cover, if necessary.

Establish the Crop

I put drip irrigation tape parallel to each row offset about 8-10”. Mammoth growing alone next year will be thinned to 24 inches apart to provide room for full head development and to let some sunshine reach the living mulch in the alleys. I do some shallow cultivation at the edges of the strips to reduce early competition from annual weeds and living mulch.

Improve the Living Mulch

At various times during the year I broadcast green manures to improve the living mulch. Depending on the season, after mowing, I may broadcast clovers, buckwheat, mustard, sorghum sudangrass, annual ryegrass, forage chicory, winter rye or other soil improvement crops onto the alleys. This Fall I tried out an overwintering variety of camelina.

To bury the seeds a little I agitate the surface lightly with a 5-shovel wheeled cultivator or a lawn dethatcher cut down to 24” wide and set up to be pushed by hand. Then I firm the seed to soil contact with my home-made push-cultipacker.

Watch the Sunflowers Grow

Once the sunflowers were established I fertilized the strips again in midsummer when the crop was about two months old. I watered when rain was sparse. I watched the flower heads grow, and waited for the signs that they were ready to harvest. Next year I will plant dry pole beans to grow up the sunflowers.

Some sunflowers would have fallen over if not for the companion planted corn and a wooden tomato trellis in the next section of the garden. Maybe they need staking or some sort of support railing or wire at about 4 feet off the ground.

2. Harvest Sunflower Heads and Process the Seeds

Harvest 10/8/23

The heads are ready to harvest when the back starts to turn yellow, individual flowers start to fall off, and birds start to eat the seeds. Cut heads with no stalks if you plan to dry them flat on racks. Cut short stalks to use as a handle if you plan to thresh by rubbing the heads on a screen.

The moist, cool northeast fall climate can make heads moldy before a long season variety is ready to harvest. To reduce risk of mold, heads can be harvested before they are ready because fully formed immature seeds will mature after harvest. I probably could have harvested a week or more earlier.

Sunflower stems are set aside to be chopped up and spread on the garden. Roots are left in the ground to improve soil organic matter.

Dry the Heads

The seeds thresh out more easily when the heads are bone dry. Wet or moldy areas should be removed before bringing the heads inside. I tried to dry heads on a tarp on the floor, ventilated with a box fan. It may be better to place on open racks in a warm, dry, well-ventilated shed or room. Next year I will try cutting open or removing the backs of the heads to allow the seeds to dry from both back and front.

Thresh the Seeds from the Heads

Break off and throw out any pieces of heads that are still wet or moldy. You can wear gloves and rub seeds off heads by hand into a basket. It may be easier to scrape the seeds off on a half-inch screen on a bucket. One video showed them beating a very dry head with a small club to loosen seeds, then sweep them off by hand. I will try that approach next year.

Separate seeds from waste bits of the heads with stacked ½” and ¼” screens. Large pieces of waste are held back by the 1/2” screen. The crop of mature large seeds are held back by the 1/4” screen. Small seeds and small pieces of waste fall through it. I let squirrels feed on the small leftover seeds in the centers of the heads and return the empty heads to the garden.

Dry the Seeds

Drier seeds are more brittle and split open more easily for dehulling. I dried the seeds in an old feed bag over a hot air floor register. For larger amounts of seeds I may need another approach to drying such as blowing warm, dry air through perforated pipe set into a five-gallon bucket of seeds

Dehull the Seeds

I hoped for fairly easy dehulling with a large-seeded snack sunflower variety and it worked well this year. I cracked the seeds with a hand cranked Corona mill by setting the plates just far enough apart for seeds to enter and get split as they roll between them.

After the first pass through the mill, I screened the cracked seeds with a 1/4” screen stacked on top of a 1/8” screen over a five gallon bucket.

Large pieces of shell and uncracked seeds are held back by the ¼” screen. Reset the plates on the Corona mill slightly narrower to crack smaller seeds and put this fraction through the Corona mill again.

The hulled nutmeats and small pieces of shell are held back by the 1/8” screen. That fraction contains the crop and requires further cleaning to separate the shells from the nutmeats. Shell dust and tiny pieces of broken nutmeats fall through the 1/8” screen. This waste is returned to the garden.

Separate Nutmeats from Shells

I separate the nutmeats from cracked shells with a vacuum seed cleaner I made following plans at: https://www.realseeds.co.uk/seedcleaner.html Suction from a household vacuum cleaner is applied to the top right side of the seed cleaner to create an updraft in the separation column on the left. When suction force is just right, seeds fall down into a bucket at the bottom of the separation column, while shells are pulled up and over to accumulate on the right side.

The plans call for a gated air leak in the back of the seed cleaner to control the force of suction. Instead I use a router speed controller (rheostat) in the power line to the vacuum cleaner to reduce the power (and force of suction) until no seeds are being drawn up and over with the waste shells. The waste shells are returned to the garden.

I run the nutmeats through the separation column several times to get most of the shells out, but some shells and small whole seeds still remain mixed in with the nutmeats.

Flotation to Separate the Last Shells

Shells and whole seeds float in water while nutmeats sink. Place nutmeats with shells into a bowl, fill it with water, and pour off the floating shells and seeds. Do this two or three times until all the shells have been removed.

Fully cleaned nutmeats can be used in food. Be sure the nutmeats are dry before using them to make oil.

3. Make Sunflower Oil

Press Oil

I use a Piteba hand-cranked, spiral press made in the Netherlands. The spiral is stainless steel, while the body of the press is steel pipe. The Piteba press includes a small oil lamp that heats the seeds during pressing to increase oil flow.

For pressing sunflower oil, Piteba recommends leaving the end cap wide open. This results in easier cranking but maybe reduced oil yield. I was able to press one pint of oil from three quarts of nutmeats or about 16% oil extraction by volume.

The oil cake will turn to rock if left inside the end cap after pressing. It will soften when soaked in water, but is still difficult to get fully cleaned up. Other users have suggested running dry sushi rice through the press at the end of the oil run to push out all the sunflower seed cake. Crushed rice is supposed to be easier to clean up. I will try that next season.

Modify the Piteba Press to Improve Oil Yield?

The pressure generated by the spiral to extract the oil depends on the size of the exit. Although cranking resistance was fairly easy with the standard 1” to 1/2” transition end cap wide open, oil extraction seemed incomplete as I saw oil dripping off the end as the cake came out.

Cast iron plumbing transitions from 1/2” to 3/8” and 1/2” to 1/4” are readily available at hardware stores. Next season I will try out different exit sizes with fully cleaned nutmeats to compare the effect on cranking difficulty and oil extraction.

Oil Cake

The residual nutmeat after oil has been extracted is the leftover oil cake. Oil cake can be used as high protein animal feed, high nitrogen fertilizer, or, when no shells are included, it can be used in food. Next year when I press oil from fully cleaned nutmeats I will try out including raw or toasted oil cake in foods such as fruit and nut bars, granola, baked goods, or maybe even nut butter (with some oil added back).

Clean the Raw Oil

Raw oil contains some debris from the nutmeats, giving it a muddy, opaque appearance. I strained it through a fine kitchen strainer to remove larger pieces of debris. Then I put the oil in bottles in the refrigerator and let the smaller pieces settle out for a few days. This resulted in slightly cloudy yellow oil over dark brown sediment. I carefully poured off the oil, leaving behind the sediment.

With larger volumes of oil I will try to filter the sediment to reclaim some of the oil. I have some food grade maple syrup prefilter material I may try. I also plan to try out a pear-shaped glass separatory funnel with a narrow bottom and stopcock that should help separate the sediment precisely without loss of good oil.

The oil will clarify further over time in storage, as the even smaller particles settle out resulting in clear yellow oil. Waxes may also precipitate and settle out at refrigerator temperatures.

Properties and Uses for Raw Sunflower Oil

Raw sunflower oil contains unsaturated fats that will degrade when exposed to air and light at room temperature. It is best used fresh. It should be stored in sealed, dark glass bottles with minimal headroom to reduce light and air exposure. Keep bottles in a refrigerator or cold room.

It is a thin, light oil. I found no odor and no particular flavor. Next year I may try toasting some of the sunflower seeds before pressing the oil to see if it imparts an interesting flavor.

While commercial sunflower oil has a high smoke point, raw unrefined sunflower oil reportedly has a smoke point of only 225º Fahrenheit. That is not much higher than boiling water. I plan to try to measure the smoke point of the oil I made before considering whether I should limit how I use it. Like any oil, it can ignite when heated past the smoke point.

Low Tech Oil Refining?

I am not sure why I would want to refine my oil. The oil is clear after fully settling out in the refrigerator. There is no offensive odor. Maybe if refining helped stabilize it to keep longer or have a higher smoke point it could be useful.

Cooling sunflower oil near freezing and separating the waxes that precipitate was a traditional approach called “Winterizing.” I just let it settle out in the refrigerator. Over time a light tan sediment formed that I suspect is composed of waxes.

“Water degumming” dissolves some of the phospholipids into a water phase that is easily separated from the oil. This could be useful to remove odors if there were any. But it also removes tocopherols and other antioxidants that people want.

Summary and Future Plans

Oil was pressed from dehulled Mammoth sunflower seeds. Dehulling and cleaning the nutmeats was fairly easy with available small scale equipment. Pressing oil from the nutmeats with hand labor was also fairly easy. A clear, yellow, thin oil was obtained.

To build on my experience in 2023, I plan to try out some improvements in 2024:

• Plant a whole garden section to sunflowers (90 plants at 2 foot spacing) to try to make a gallon of oil.
• To avoid cold, wet fall weather at harvest, I will plant earlier, harvest earlier, and trial Super Snack sunflower that has fewer days to maturity than Mammoth.
• Try out several different ways to support the tall sunflowers as the heads mature and get heavy.
• Try out other ways to dry down the heads after harvest.
• Try threshing heads by beating with a narrow board or club.
• Modify the end cap of the Piteba press to increase pressure and more fully extract the oil from the nutmeats.
• Press fully cleaned nutmeats and try using the oil cake in food.
• Put sushi rice through the press at the end of the run to allow for easier cleanup of the end pieces.
• Try roasting the sunflower seeds before pressing to see if it creates a pleasant “nutty” flavored oil.
• Try to determine the smoke point of my oil to be more certain about its properties and uses.
• Try out a 2-liter separatory funnel, first for separating clean oil from sediment after settling out, and later for separating water from oil after trying “water degumming.”

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Sesame Whole Grain Crackers

1. Mix dry ingredients together.

• 2 cups fresh whole grain flour (need weight to balance wet to dry better)
• 1 teaspoon salt
• 1 teaspoon baking powder
• 3 tablespoons sesame seeds (maybe some black sesame for color)

2. Mix wet ingredients together.

• ¾ cup water
• ¼ cup sunflower oil (any oil you want, really)

3. Whisk wet ingredients together a bit, then mix wet with dry to form moist ball. Let it rest about 30 to 60 minutes.

4. Pre-heat oven to 375.

5. Prepare the crackers.

The dough may be quite wet and sticky. Turn out on floured board and knead a bit, adding small amounts of flour to the board until the dough feels right: fairly dry, sort of rubbery.

Cut into four to eight parts, flour the moist cut edges.

Press one portion flat onto the board by hand, turning to keep both surfaces floured.

Roll out with a rolling pin until about 1/16” thick. Add flour to board as needed to keep it from sticking.

Cut into roughly 2” squares and place them on a cookie sheet. You can bake these, but I like to make them thinner and a uniform thickness by putting them through pasta machine rollers set on 0 (thickest).

6. Bake the crackers.

Bake at 350-375 for 8 minutes. Turn the crackers and bake another 8 minutes. Cool on a cookie rack. If they are too toasted (“burnt”) try 350 for 8 minutes on a side or shorter time at 375. If too soft, try longer on each side.

I use whole grain flour that I make from heritage wheat I grow myself. It adds a slightly bitter flavor (in addition to the slight bitterness of toasting) that pairs well with cheese. I think the flavor people recognize and like is more the toasted sesame seeds than the whole grain heritage wheat.