Old olive mill’s new lease on life
An old olive mill turned museum is more than nostalgia. The way oil is pressed shapes the way it tastes, and the leap from stone wheels and screw presses to today’s stainless steel is one of the great quiet revolutions in food. Here is how the olive mill changed — and what it changed.
When a bank or a foundation restores an old olive mill and opens it as a museum, it is preserving far more than picturesque machinery. The mill is where the fruit becomes oil, and every stage of how that is done leaves its mark in the bottle. The history of olive-oil milling — from stone wheels turned by animals, through the great screw and hydraulic presses, to the sealed centrifuges of a modern plant — is really the history of olive oil quality itself. Walk through a good olive museum and you are reading that story in iron and stone.
The old way: stone and pressure
For most of history, milling meant two steps. First the olives were crushed — pit and all — under enormous stone wheels turning in a basin, a method so effective that stone mills survived into the modern age. Then the resulting paste was spread onto stacked fibre mats, the scourtins, and squeezed under a screw or hydraulic press until the oil and water ran out to be separated. It worked, and in careful hands it made superb oil. But it was slow, hard to keep scrupulously clean, and the paste sat exposed to the air — and air, warmth and time are the enemies of fresh oil.
The modern leap: the centrifuge
The revolution came with the continuous centrifugal system. Instead of pressing mats, the crushed paste is churned gently and then spun in an enclosed centrifuge that flings the oil out from the water and solids by sheer speed. The gain is not just efficiency. Because the process is fast, cool and closed to the air, it protects the fresh, fragile aromas and the antioxidants that a slow, exposed old press could lose. Most of the world’s best extra virgin today is made this way, milled within hours of the harvest at carefully controlled low temperatures.
What the museums quietly teach
Here is the honest nuance a romantic mill visit can blur: newer is, on the whole, better for freshness. It is tempting to assume the old stone-and-press oil was purer, but the truth is that a well-run modern mill usually makes cleaner, fresher, more consistent oil than the old ways could — precisely because it keeps the paste cold and away from the air. The old mills are worth preserving as heritage and as a lesson in ingenuity, not as proof that the past pressed better. Respect the craft; buy the fresh oil.
| Era | How the oil was extracted | Strength | Weakness |
|---|---|---|---|
| Ancient stone mill | Stone wheels crush fruit in a basin | Simple, durable, effective crush | Slow; paste exposed to air |
| Screw / hydraulic press | Paste squeezed through fibre mats | Made superb oil in careful hands | Hard to keep clean; oxidation risk |
| Modern centrifuge | Paste spun to fling out the oil | Fast, cool, sealed — protects freshness | Higher capital cost |
The takeaways
- How oil is milled shapes how it tastes — the mill is not a detail.
- The old way crushed with stone and squeezed through fibre mats.
- The modern centrifuge is fast, cool and sealed, protecting fresh aromas.
- A good modern mill usually makes cleaner, fresher oil than the old presses.
- Prize the old mills as heritage, but buy oil pressed fast and cold.
How olive oil is milled: common questions
What did an old olive mill do?
It crushed olives under large stone wheels, then spread the paste on fibre mats and squeezed it under a screw or hydraulic press to release the oil, which was then separated from the water.
What are scourtins?
The round fibre mats used in traditional presses. Layers of paste-filled mats were stacked and pressed together so the oil and vegetation water ran out.
How is olive oil made today?
Most modern oil is made with a continuous centrifuge: the crushed paste is gently churned and then spun in a sealed machine that separates the oil by speed, fast and cool.
Is old-fashioned pressed oil better?
Not usually. A well-run modern mill keeps the paste cold and away from air, so it typically makes fresher, cleaner and more consistent oil than the old exposed presses could.
Why does milling speed matter?
Fresh oil is fragile. Milling quickly after harvest, cool and sealed from air, protects the aromas and antioxidants that time, warmth and oxygen would otherwise destroy.
I love a restored old mill as much as anyone — the great stone wheels, the stacked mats, the sheer ingenuity of it. But do not let the romance fool you into thinking the old presses made better oil. They did not, as a rule. Paste sitting exposed to the warm air is oxidising by the minute, and the modern sealed centrifuge exists precisely to stop that. Visit the museum for the heritage and the craft. Then go home and buy oil that was milled fast, cold and fresh — that is where the flavour actually lives.
Drawn from the documented evolution of olive-oil milling, from stone mills and screw presses to the modern centrifugal system.