Pour freshly pressed oil into a tall, narrow vessel and leave it undisturbed: the first 12-24 hours separate the water and emulsion from the oil, and 3-7 days let the fine particles sink. Decant the clear top oil carefully, then filter it by gravity through several layers of muslin or fine linen, never forcing it through the cloth.
Part of Oil Pressing at Scale
Clarifying pressed oil: settling in layers, decanting, gravity filtration through cloth and what to do with the sediment and emulsion.
Settling Works Because Oil, Water And Solids Differ In Weight
Fresh oil from the press carries water, protein and fine particles. In a tall, narrow vessel they sink or separate. The wiki’s oil-extraction page describes three layers after 12-24 hours: pure oil on top, an oil-and-water emulsion in the middle, and water with sediment at the bottom (Oil Extraction). The carrier gives a longer time, 3-7 days, for the oil to clear of fine particles.
The two figures describe two stages and do not conflict: the first day or so separates the water, the following days clear the fines. Decant after the first stage, move the oil to a clean vessel, and let it settle again. A second settling in a fresh vessel gives the purest oil.
Method: Settle, Decant, Filter
Step 1: Pour the pressed liquid into a tall, narrow vessel such as a pottery jar, and leave it still.
Step 2: After 12-24 hours, draw off the top layer with a ladle, a siphon or by pouring slowly, stopping at the emulsion.
Step 3: Keep the middle layer. Return the emulsion to the press or warm it gently to separate more oil; discard the water and sediment or feed it to animals.
Step 4: Settle the decanted oil again for 3-7 days in a clean, covered vessel.
Step 5: Decant a second time and leave the last finger of oil with the sediment.
Step 6: Filter by gravity. Line a funnel with several layers of muslin or linen, pour the oil in, and let it drip through; do not squeeze or force it. Oil is thick and filters slowly in a cool place; warm it slightly if it is too slow.
Step 7: Fill dark containers and seal them (Oil Storage Containers and Conditions).
Worked Example: Losses In A Batch
Suppose a batch of 26 litres of pressed liquid (the oil volume in the processing-steps example, ignoring the water) loses 2 litres of emulsion and sediment at the first settling and 1 litre at the second. The clear oil is 26 - 2 - 1 = 23 litres, and the emulsion and sediment left behind should be returned to the press, because 3 litres is 12% of the batch (Processing Steps). The 2 and 1 litre losses are example figures, not measurements; log your own.
What You Need
- Tall, narrow vessels, clean and covered, at least two
- A ladle or siphon
- Muslin or fine linen, washed, with a funnel or frame to hold it
- A cool, still, shaded place
Common Mistakes
- Stirring the vessel. It remixes the layers.
- Pouring to the last drop. The bottom contains the sediment.
- Squeezing the cloth. It forces fines into the oil.
- Dirty cloth. Old oil in the weave spoils new oil; wash and dry it.
Spoilage hides in the layers
The water and emulsion layers go bad quickly, and oil left sitting on them spoils. Do not leave oil on its sediment for weeks. Keep flame away from oil and oily cloth, which burn.
What’s Next
- Learn next: Oil Storage Containers and Conditions - where the clean oil goes
- Combine with: Rancidity Prevention - keeping it clean