Making Olive Oil the Traditional Way

The Olives Go Into the Hopper

The Olives Go Into the Hopper

In Tuscany (and much of the rest of Italy) quality olive oil all starts the same way: The olive grower spreads a silken parachute around the base of the olive tree, rests a ladder against the branches, and then climbs up into the tree and picks the olives, by hand. What’s next? The press, ideally as quickly as possible, because, as Francesco Nardi of the Azienda Agricola Il Cavallone, which has about 1700 olive trees in the hills downriver from Florence, points out, the olives start to deteriorate the moment they’re picked.

Regardless of the kind of press, the first step is to put the olives in a hopper that will start them on their journey through the system. The paths are quite different, however, for olives that go through modern industrial presses, and those that go through traditional presses. Francesco’s press dates to the 1930s, and is one of the oldest still operating in Tuscany.

And From the Hopper to the Grinder

And From the Hopper to the Grinder

Traditional olive presses employ millstones to grind the olives, reducing them to a paste from which the oil can be extracted. Unlike the millstones of a flour mill, which are horizontally mounted, with one turning atop the other, the millstones of an olive press are vertically mounted and rotate in a tub, crushing the olives against the floor of the tub.

The Millstones Grind the Olives to a Paste

The Millstones Grind the Olives to a Paste

The grindstones of Francesco’s press are made of granite, about 4 feet in diameter, and a bit more than a foot thick. They weigh about 1.5 metric tons each, and are turned by an electric motor. The paste is ready for the next step when it becomes oily, Francesco says. It takes about a half hour of grinding to reach this stage.

The Paste is Spread on Mats called Fiscole

The Paste is Spread on Mats called Fiscole

The paste goes into a second tub called the gramolatrice, where it is stirred by several rotating paddles. The stirring breaks up the water-oil emulsion derived from the grinding process, and thus forms droplets of oil that can be more easily extracted from the paste during the subsequent pressing. Again, the stirring phase takes about a half hour.
When it’s done, Francesco’s assistant puts the paste onto round pads called Fiscoli, which he stacks in the press. About a kilo (2 1/4) pounds of paste per pad, and Francesco’s assistant stacks the pads in sets of five in the press, separating each 5-pad stack with a steel plate.
It’s impossible to get all of the olive oil residue out of the Fiscoli, and since it would become rancid from one year to the next Francesco repurchases them every year, from an outfit in Perugia. In the past they would have been produced on the farm, probably from hemp.

The Fiscole are Stacked in the Press

The Fiscole are Stacked in the Press

The fiscoli, with their layers of olive pasted, are stacked in the press, in five-pad stacks separated by steel plates.

Loading the press takes 45 minutes to an hour, and by the time the press is half loaded the weight of the stack is already pressing oil from the lowermost disks.
And this brings up an important point: One of the things one often hears now from olive oil producers is how important it is to keep the oil from oxidizing. In fact, some modern presses are pressurized with nitrogen (an inert gas) to keep oxygen from reaching the olives as they are ground and the resultant paste is stirred. No oxidation, they say, makes for better oil.

However, Sandro Bosticco, an expert olive oil taster, tells me that the situation isn’t quite that simple. While it’s true that exposure to oxygen leads to deterioration, exposure to oxygen during the grinding and gramolatura phases appears to promote the development of the compounds that give olive oil its distinctive (and captivating) aromas.

The Press, Ready to Go

The Press, Ready to Go

Therefore, what one wants is to strike a balance — some exposure to oxygen during the pressing, but not too much. And as little exposure as possible subsequently.

With the press stacked — this volume of olive paste will yield 25-30 kilos, or a bit more than 30 liters (30 quarts) of oil) — Francesco turns on the hydraulics, and the floor of the press begins to rise, pressing the pads against the top of the press.

An Oil and Water Slurry Drains from the Press...

An Oil and Water Slurry Drains from the Press…

Oil begins to drip down the sides of the stack, collecting in a trough at the base of the press, from whence it drains into a holding tank.

A Pressure of 400 Atmospheres

A Pressure of 400 Atmospheres

Olive presses squeeze hard. This isn’t wine making, where one hears about soft pressing and people wince at the idea of more than two atmospheres. Rather, the press cranks up to 400 atmospheres (400 k/square cm, close to 900 pounds) and maintains that pressure by continuing to lift the floor of the press as the oil seeps out. It takes about a half hour to press the stack, after which Frencesco’s assistant releases the pressure, removes the pressed paste (it goes back to the olive groves) and starts the cycle anew.

The Slurry From The Press Needs Filtering...

The Slurry From The Press Needs Filtering…

The oil that emerges from the press is anything but pure — there’s still quite a bit of solid matter in it, and also a fair amount of water. So Francesco pumps it though two settling tanks, where some of the solid material settles out, and them into a centrifuge that separates the water from the oil.

Like the rest of his equipment, it dates to the 30s and as such was one of the first generation of centrifuges used to separate the oil from the water. Before then they used a longer succession of settling tanks to remove solid matter, and then a special terracotta urn with a siphon — since water is heavier than oil it settles, and then the weight of the oil forces it up and out through the siphon.

Using a centrifuge is of course both easier and much faster, and since we are by now at the stage when it is important to limit exposure to oxygen, the introduction of the centrifuge resulted in a dramatic increase in the quality of the oil.

Newly Pressed Oil, Fresh From the Centrifuge...

Newly Pressed Oil, Fresh From the Centrifuge…

And here we have it! Francesco Nardi’s traditionally pressed olive oil!

How Olive Oil is Pressed in a Modern Press
Andar Per Olio, About Olive Oil, and Purchasing & Storing It

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Categories: Italian Ingredients, Tecniques

Author:Cosa Bolle in Pentola

Italy boasts an astonishing number of varietals, denominations, and wines, and tremendous changes are sweeping the land. New wines are being created, new DOCs are being introduced, and the existing denominations are overhauling their regulations both to reflect the practices adopted by their member wineries and to favor improvements in quality. Even the most staid and stolid region can flower seemingly overnight, emerging with exciting new wines and wineries that require rewriting the enological maps and rethinking one's positions. And, of course, recipes too, because cuisine and wine are closely intertwined and it's difficult to imagine one without the other.

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