Oil is made in a fixed order: clean the seed, dry it to 8-10% moisture, dehull sunflower, crush it, warm it to 120-160 degrees F, press it, settle and filter the oil, and store it. From 100 kg of seed holding 40% oil, a press recovering 60% gives 24 kg of oil, a second pressing of the cake adds 10-30% of that, and 68.8-76 kg of cake remains for animals.
Part of Oil Pressing at Scale
The sequence of steps from raw seed to stored oil, with a mass balance for 100 kg of seed and the points where oil is lost or spoiled.
The Order Is Fixed And Each Step Protects The Next
The carrier lists the steps: seed cleaning, drying, dehulling for sunflower, crushing, heating, pressing, then filtering and storage. Skip one and a later step fails: wet seed clogs the press, uncleaned seed chips the crusher, unwarmed seed gives less oil, unsettled oil spoils sooner.
A Mass Balance For 100 kg Of Seed
Assume sunflower seed at 40% oil (inside the carrier’s 35-45%).
- Oil in the seed: 100 x 0.40 = 40 kg
- First pressing at 60% recovery (inside the corpus’s 50-70%): 40 x 0.60 = 24 kg of oil, which is 24 / 0.92 = 26 litres at 0.92 kg/L
- Cake after the first pressing: 100 - 24 = 76 kg, holding 40 - 24 = 16 kg of oil, a residual of 16 / 76 = 21%
- Second pressing, which the carrier says yields 10-30% of the first: 24 x 0.10 = 2.4 kg up to 24 x 0.30 = 7.2 kg
- After two pressings: oil 26.4 to 31.2 kg, which is 66% to 78% of the oil in the seed; cake 100 - 26.4 = 73.6 down to 100 - 31.2 = 68.8 kg, with residual oil 13.6 / 73.6 = 18% down to 8.8 / 68.8 = 13%
The carrier’s description of the cake as 10-15% residual oil is therefore what a well-managed pressing plus a second pressing leaves, not what a single hand-press pass leaves.
What Each Step Does
| Step | Purpose | Where covered |
|---|---|---|
| Clean | Remove stems, stones, soil that chip the crusher | Seed Cleaning and Drying |
| Dry | 8-10% moisture; wetter clogs, drier yields less | same |
| Dehull (sunflower) | Hulls lower yield and oil quality | same |
| Crush and warm | Open the oil cells; seed warmed to 120-160 degrees F releases 10-20% more oil | Crushing and Heating |
| Press | Squeeze slowly; 15-30 minutes a batch | Pressing and Extraction |
| Settle and filter | Remove fines and water | Settling and Cloth Filtration |
| Store | Dark, full, cool, sealed | Oil Storage Containers and Conditions |
What You Need
- Clean, dry seed, weighed
- A crusher, a heater, a press and cloth
- Scales and a log, so each batch’s oil and cake are weighed and the recovery is known
- Containers for oil, cake and hulls
Method: Run The Balance Yourself
Step 1: Weigh the seed and estimate its oil content from the crop table.
Step 2: Press and weigh the oil. Convert litres to kilograms at about 0.92.
Step 3: Divide oil out by oil in for the recovery; replace the assumed 60% with your own.
Step 4: Weigh the cake and check it against seed minus oil.
Step 5: Log it so the next season’s plan uses measured numbers.
Common Mistakes
- Skipping the log. Without recovery figures every plan is a guess.
- Pressing hot to chase recovery. Heat above 160 degrees F degrades the oil.
- Pressing once and discarding the cake. A second pressing adds 10-30% of the first.
Heat, dust and moving machinery
Warm seed and hot oil burn: do not exceed 160 degrees F and handle pots with cloths. Seed dust is combustible: sweep it, keep open flame out of the crushing area and never test for dust with a flame. Guard the crusher and press, and stop them before clearing a jam.
What’s Next
- Learn next: Seed Cleaning and Drying - the first steps
- Combine with: Oil Yield per Acre by Crop - scaling the balance to an acre