Green Gold: Innovations in Olive Oil Production

Spain is the largest producer of olive oil worldwide. Savour the story of the evolving technology behind one of the world's favourite staple foods.

By Parque de las Ciencias Andalucía-Granada

Parque de las Ciencias de Granada

Olive groveParque de las Ciencias Andalucía-Granada

From 3000 BC

The first olive trees were cultivated in 3,000 BC and the properties of olives have been recognized throughout history.

Olive oil was a key part of the lives of ancient Mediterranean civilizations and is now known as "green gold" due to its high market value.

Olive groveParque de las Ciencias Andalucía-Granada

Hundred-year-old olive trees

These trees are from the Vega de Granada region.

Now at the museum, they are a testament to the local roots and traditions of olive tree cultivation and olive oil production.

Preindustrial mill Preindustrial millParque de las Ciencias Andalucía-Granada

Energy to Power a Mill

The earliest mills were powered using the physical strength of men or animals.

Later, hydraulic mills used the force of water to move the stones to grind the olives. However, the real revolution in olive oil extraction came with the arrival of electricity.

The Spanish word for olive mill, 'almazara', comes from the Arabic for 'pressing place'.

Preindustrial mill Preindustrial millParque de las Ciencias Andalucía-Granada

Eighteenth-century mill

Animal-powered mill of Roman origin.

A mule normally dragged the upper millstone around to grind the olives into a paste.

The paste was then pressed by hand at room temperature to extract the oil.

Olive millParque de las Ciencias Andalucía-Granada

The Padul olive mill

This mill belonged to the Martín-Martín family.

It was the last one standing in Padul (a village in the Valle de Lecrín region of Granada) and operated until 1972.

Twenty years later, the Parque de las Ciencias recovered it and fully restored it to working order.

It is now part of a collection of items of scientific, technological, and industrial heritage that are on show every day at the museum.

RheostatParque de las Ciencias Andalucía-Granada

Electrical control panel

This electrical control panel, rheostat, and motor are the original elements that powered the Padul mill until 1972.

The process of extracting olive oil continued to develop after 1950, thanks to electricity.

ScaleParque de las Ciencias Andalucía-Granada


The first job in the mill was to weigh the olives.

These mechanical scales were made by the company Hijos de A Ariso in the early 20th century.

HopperParque de las Ciencias Andalucía-Granada

Hopper and endless screw

An endless screw is a circular mechanism that helps move the olives move easily from the hopper to the lower millstone.

Oil millParque de las Ciencias Andalucía-Granada

Stone mill

This mill has a lower millstone made of stone and 3 other cone-shaped ones to break up the olives and produce a mass containing the olive skin, flesh, and stone.

BoilerParque de las Ciencias Andalucía-Granada


This is a key part of an olive oil mill as it adds hot water to the mixer, which brings the mass to an optimum temperature.

BeaterParque de las Ciencias Andalucía-Granada

Thermal mixer

This element made by a local foundry consists of a double-jacketed vessel through which hot water circulates.

This provides enough heat for preparation and pressing without the water needing to be mixed in with the ground olive mass.

The design was a true innovation that improved the process of extracting olive oil.

Hydraulic pumpParque de las Ciencias Andalucía-Granada

Hydraulic pump

The introduction of a hydraulic pump into the oil extraction process meant that a hydraulic press could be moved effectively without having to use physical force.

Hydraulic pressParque de las Ciencias Andalucía-Granada

Hydraulic press

This was a significant development in the oil extraction process as pressing had previously been done by hand, requiring huge physical effort.

The thermo-mixed mass was placed on a trolley by hand, between a tower of vegetable fiber mats or filters.

This was raised towards the top of the press by the hydraulic pump to separate the oil and vegetation water from the rest of the mass.

Breakfast with bread and olive oilParque de las Ciencias Andalucía-Granada

Olive oil

Once the pressing was finished, the liquid mix was allowed to stand while the olive vegetation water separated from the oil.

All that then remained was to bottle and consume the oil. Olive oil is a healthy product and is a key element of the Mediterranean diet.

Olive centrifugeParque de las Ciencias Andalucía-Granada

Centrifuge model

Oil mills are now made from grooved cylinders or serrated discs rather than stone, and instead of being pressed, the mass is prepared in large thermal mixers, centrifuged, and then filtered.

Credits: Story

Parque de las Ciencias olive mill donated by the Martín-Martín family

Ramón L. Pérez
Miguel Ángel Molina
Antonio Navarro
Parque de las Ciencias

Parque de las Ciencias

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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