How to Make Olive Oil at Home (and How Olive Oil Is Made)

Olive oil is simply the juice of the olive, separated from water and solids without heat or chemicals. A commercial mill washes, crushes, malaxes (slowly mixes) and centrifuges the paste. At home you can make a small batch with a food processor and patience, though the yield and quality are lower than from a mill. On average, 5–8 kg of olives make 1 litre of oil.

How Olive Oil Is Made at a Mill

1. Harvest healthy olives, ideally at the green-to-purple stage, and bring them to the mill within 24 hours.
2. Clean: remove leaves and wash.
3. Crush the whole olives, stones included, into a paste with a hammer mill or millstones.
4. Malax the paste for 20–45 minutes so tiny oil droplets merge. Keeping the paste below 27 °C (81 °F) gives "cold extracted" oil.
5. Separate oil from water and solids in a decanter centrifuge (or, traditionally, by pressing on mats).
6. Clean the oil in a vertical centrifuge or let it settle, then filter if desired.
7. Store in stainless steel or dark glass, cool and away from air and light.

Making Olive Oil at Home

1. Wash 5–10 kg of fresh, ripe olives and remove stems and leaves.
2. Crush them, stones and all, in a sturdy food processor or with a meat grinder into a thick paste.
3. Stir the paste slowly for 30–40 minutes at room temperature. Small beads of oil appear.
4. Press the paste in cheesecloth inside a fruit press, or spoon off the oily liquid after letting it stand.
5. Let the liquid stand in a tall jar for several hours: oil rises to the top. Draw it off with a spoon, syringe or tap at the bottom of a separator.
6. Let the oil settle for a few days and decant it off the sediment.

Home methods extract only part of the oil, so expect less than a mill would give.

How Many Olives Make a Litre of Oil?

Fresh olives contain roughly 15–30% oil by weight, depending on variety, ripeness and water. Mills extract most of it, typically giving 12–22 kg of oil per 100 kg of olives. Riper olives and varieties like Picual and Koroneiki yield more; early green harvest yields less but gives more peppery, longer-lasting oil.

Extra Virgin, Virgin and Acidity

• Extra virgin: mechanically extracted, free acidity of at most 0.8% and no taste defects in a panel test.
• Virgin: acidity up to 2% and minor defects.
• Lampante: not fit to eat without refining.

Acidity rises when olives are damaged by fruit fly, bruised, fermented in piles or left too long before milling. Speed and clean fruit are the keys to good oil.

Storing Olive Oil

Keep oil in dark glass or tin, tightly closed, at 14–18 °C (57–64 °F). Use it within 12–18 months of harvest; oil does not improve with age.

More Olive Tree Guides

• How to Grow Olive Trees: The Complete Guide
• Olive tree yield and years to fruit
• Is olive farming profitable?
• Olive tree cold hardiness and winter care

Frequently Asked Questions

Can I make olive oil from my own olive tree?

Yes. A small batch is possible at home, but taking your olives to a local mill that accepts small lots gives more and better oil.

How many olives does it take to make a litre of olive oil?

About 5–8 kg (11–18 lb), depending on variety and ripeness.

What does cold pressed olive oil mean?

The paste was kept below 27 °C (81 °F) during extraction, preserving aroma and polyphenols.

Do you remove the pits before making olive oil?

No, the whole olive including the stone is crushed.