Oil mill and storage

Short info:

• Most vegetable oils are derived from seeds, where solvents are used to extract the fat.

• Olive oil is the only vegetable oil whose fat is obtained directly from the olive and only by mechanical means, since the oil is in the pulp.

1. defoliation and washing

Arriving at the mill, the leaves that remain are removed/defoliated from the olives with an air stream and piled separately, which are later used as compost.  The olives are then washed with clean drinking water to remove foreign matter such as soil and dust.

1. Crushing (crushing) / pressing

The olives are then crushed or pressed in a special crusher made of metal discs, resulting in a homogeneous mixture/paste, the temperature of which is constantly controlled, since overheating can negatively affect the quality of the olive oil produced. The paste obtained here contains between 15-20% oil. The rest is made up of drupes, water and solid plant matter.

1. kneading / mixing

The oil contained in the paste produced above comes in the form of minute oil droplets which are very difficult to extract from the paste. In order for them to combine to form larger oil droplets that can then be extracted, the paste must be mixed. For this purpose, at this stage, the resulting homogeneous mixture (paste) is placed in special kneaders (machines made of stainless steel containers with metal blades) that mix/stir the paste slowly and for a long time.

For the production of high-quality olive oil, kneading/mixing is carried out at a controlled low temperature, which gives the property of cold extraction up to 27 °C and thus we lose the least beneficial components such as polyphenols, vitamins, aroma and smell of olive oil. However, with cold pressing, the amount of oil is less.

The temperatures that are normally used are between 25 and 35°C. The higher the temperature is set, the faster the olive oil will extract and the more oil will be extracted. However, the quality is all the more compromised.

To better understand:

• When cooking at high temperatures in general, we already know that vitamins and beneficial components are lost or destroyed. This also happens when warming/heating the olive oil.

• Fats on surfaces such as plates, glasses or our oven are best removed with warm water than with cold. This shows us that fats dissolve better with heat and the reason for this is that the more we heat the paste, the more oil we gain.

1. centrifugation / spinning

The finished mixture/paste is then centrifuged. The centrifugal machine/separating machine (decanter) is a cylindrical container that achieves very high revolutions per minute. Thus, the most dense parts (stone, vegetable matter) of the mixture are deposited on the wall of the cylinder and the parts that are less dense (oil) are collected in the center of the container.

Once the components of the mixture have been separated, a septum is used to separate the oil from the solids of the mixture. This process is not 100% effective as there may still be solids in the oil obtained.

Another centrifuge is used to remove them. To remove these residues, the oil is pumped through another centrifuge. Then water is added. The different density of the water will carry the remaining solids towards the wall of the centrifuge and thus the pure olive oil will be separated.

Therefore, at this stage we are talking about two or three phase centrifugal separators.

1. Filter

• FILTERED

By filtering we get a transparent and shiny (clear) oil and we can guarantee that no deposits are formed, as the oil still has small amounts of suspended vegetable matter and water.

If we want to better preserve a quality olive oil, with its chemical properties and especially its aromas: let's filter it immediately after production, while the oil is still warm and at an ideal temperature of 22 degrees. So initially you lose a certain amount of polyphenols, but in small amounts, so small that it cannot be compared with the benefits that are obtained in the long term.

In this way we preserve the aromas of the olive oil better and longer.

• UNFILTERED

If we don't filter and let the olive oil rest like most do who once see it as a benefit, in a few months its degradation will begin to take place. Suspended matter and more moisture in unfiltered olive oil create favorable conditions for enzymes to work at the expense of quality. The fermentations in olive oil are catastrophic in the long run! Exactly the opposite of what we want to achieve with wine. The results of the insidious work of the enzymes can be seen in the nose (smell) and taste. In this case, the suspended matter naturally settles both in the tanks and in the filled bottles and canisters and the oil is cloudy for a long time and becomes clearer over time (months).

1. storage

The olive oil is stored in stainless steel tanks without oxygen. For an even longer shelf life, the supply of nitrogen is necessary, as this slows down the oxidation process of the olive oil. Unlike wine, olive oil loses quality over time. The oxidation process in olive oil is a continuous process that cannot be stopped.

When stored refrigerated or frozen, the olive oil crystallizes. When the olive oil returns to room temperature, the sharp temperature differences cause a shock that accelerates its oxidation. The ideal temperatures for storage are: from 12-15 degrees.

1. packaging

In the last stage of packaging / standardization (bottling), the olive oil is ideally filled into dark glass bottles or containers, sealed and provided with the appropriate label. Storage after packaging is the same as in point 6.

Olive oil categories (4 of 8 categories are cooking oils)

• Extra native (native)

• Native (native)

• Olive oil (mixture of refined olive oil and virgin olive oil)

• Olive pomace oil / olive kernel oil (mixture of refined olive pomace oil and virgin olive oil)

• Extra Virgin Olive Oil

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This is the highest category/class of quality that we obtain exclusively from the olive fruit using mechanical processes without further processing.

The first olive oil of the year made from green, unripe olives is called Agoureleo.

• acidity up to 0.8%

• Taste: Intensely fruity, spicy and bitter to very bitter

• Aroma: Intense freshness of green and olive fruits

• Colour: Yellow-green to more intense green

• native olive oil

Is the second quality category/grade, which is also obtained exclusively from the olive fruit by mechanical processes without further processing.  

• Acidity 0.9% to 2.0%

• Taste: Slightly fruity, not so bitter but a little sweeter

• Aroma: Fresh greens and olive fruits

• Colour: Yellow to light yellow-green

• olive oil

In this category we are talking about non-edible olive oil called Lampante olive oil, which we also obtain from the olive fruit, through mechanical processes without further processing.

In order for the olive oil to be palatable (edible) and get the name olive oil, we have to go through a process called refining and add a small percentage of virgin or extra virgin olive oil.

• Acidity above 2.0% to be edible up to 1.0%

• Taste: Unpleasant

• Odor: Disturbing

• Colour: Colorless

• Refined olive oil

The refined olive oil is a category of oil that is not yet edible while it is obtained from the processing (refining) of poor quality olive oils.

What does refining do:

• Cleans and degumming: cleaning of the oil.

• Deacidified: Neutralizes the acidity and sets it to zero.

• Deodorizes: Removes (neutralizes) unpleasant odors and tastes.

• Bleached or Discolored: Removes the color.

• Winterized: Makes the oil liquid even at lower temperatures.

The conditions during the refining process of an oil have a negative impact on its properties and therefore its quality. After the refining phase is complete, the resulting oil is odourless, colorless and tasteless.

• Olive pomace oil / olive kernel oil

In this category we are talking about an inedible olive oil called virgin pomace oil that we obtain from olive pits through chemical treatment.

To make it palatable (edible) and to call it olive pomace oil / olive kernel oil, it has to go through the refining process and a small percentage of virgin or extra virgin olive oil has to be added.