Processing Olive Oil in Italy
Watch olives pressed the old Italian way and it looks almost unchanged since antiquity: great granite wheels crushing the fruit, paste spread on mats and squeezed, a centrifuge spinning the water from the oil. Beautiful to see — but most of it has quietly given way to something faster and cleaner.
There is a scene every olive-oil lover has watched at least once: inside an Italian frantoio, enormous granite wheels turn slowly in a stone basin, crushing whole olives — flesh, skin and stone — into a dark paste. It is one of the oldest food processes still performed more or less as it always was, and it is genuinely lovely to watch. But behind the romance is a simple chain of physics, and understanding it tells you far more about your oil than the picturesque wheels ever will.
The stone wheels
The crushing comes first. The great wheels — molazze — roll over the olives in their basin, tearing the fruit apart and beginning to free the oil held inside its cells. Stone crushing is slow and gentle, and its defenders argue it develops rounder, less bitter flavours. Its drawbacks are just as real: it is slow, it is hard to keep scrupulously clean, and the paste sits exposed to air the whole time, which invites oxidation. It is a wonderful thing to see and a demanding thing to run well.
The mats and the press
Next the paste is spread across round fibre mats — once natural hemp or esparto, now usually synthetic — which are stacked one on another into a tall column and squeezed under pressure. The oil and vegetable water ooze out together and run off to be separated. This is the literal press in cold-pressed, and the origin of first press. It works, and for centuries it was the only way — but the mats are notoriously hard to clean, and old paste clinging to them can taint a fresh batch with a rancid, fusty off-note. That hidden hygiene problem is the single biggest reason the method has faded.
The centrifuge
Finally the mixed liquid is spun in a centrifuge, which throws the heavier water outward and leaves the lighter oil to be drawn off — the step the videos make look almost magical, and the one piece of the old chain that modern mills kept and perfected. It really is that simple in principle: crush, separate the oil from the water, bottle. What changed is everything around the centrifuge.
What quietly replaced the romance
Most serious Italian mills today have swapped the stones and mats for a closed, continuous system: a steel crusher, a temperature-controlled malaxer, and a horizontal centrifuge (a decanter) that separates oil, water and solids in one clean, fast, enclosed pass. It is less photogenic, but it is faster, far more hygienic, and it protects the fresh, green flavours that slow, air-exposed stone-and-mat pressing tends to lose. So enjoy the old images for their beauty — but do not assume the antique method makes the better oil. More often than not, the unglamorous modern mill does. The same tour of tradition versus reality runs through how olive oil is cut.
| Stage | What you see in the video | What it does |
|---|---|---|
| Crushing | Granite wheels in a basin | Ruptures the fruit to free the oil |
| Pressing | Paste on stacked mats, squeezed | Forces oil and water out together |
| Separation | A spinning centrifuge | Flings the heavier water off the oil |
| The catch | Looks timeless and pure | Mats are hard to clean; paste oxidises in air |
What to take from the old method
- The core physics never changes: crush, separate oil from water, bottle.
- Stone-and-mat pressing is beautiful but demanding — hygiene is its weak point.
- A modern enclosed mill is usually cleaner and fresher, not worse.
- Judge oil by taste and harvest date, not by how antique the mill looks.
Traditional Italian olive pressing: common questions
How were olives traditionally pressed in Italy?
Whole olives were crushed by granite wheels into a paste, spread on fibre mats, stacked and squeezed, then the oil was separated from the water by centrifuge.
Is stone-milled oil better?
Not necessarily. Stone crushing is gentle and traditional, but slow and hard to keep clean, and the paste oxidises in the open air. Modern enclosed mills often make a fresher oil.
What does the centrifuge do?
It spins the mixed liquid so the heavier vegetable water separates from the lighter oil, which is then drawn off. It is the one old step modern mills kept.
Why did mat-pressing fall out of use?
Mainly hygiene: the fibre mats are very hard to clean, and old paste clinging to them can give a fresh batch a rancid, fusty taint.
Does ‘first press’ still mean anything?
Little. It comes from the mat-and-press era; modern mills extract once by centrifuge, so the phrase is largely marketing today.
The old Italian press is a joy to watch and I would not want it to vanish — but do not confuse beauty with quality. Those stone wheels and woven mats sit open to the air and are the very devil to keep clean; a scrap of old paste on a mat can turn a fresh batch rancid. The single step the modern mill kept is the centrifuge; everything else it enclosed, cooled and sped up, and the oil is usually the better for it. Buy on taste and harvest date, not on how antique the frantoio looks in the film.
Drawn from traditional and modern Italian milling practice.