Plant oils compared: cold pressing vs. industrial oil production

How are plant oils produced industrially?

In industrial oil production, the focus is on extracting as much of the oil contained in the raw material as possible. To achieve this, the raw materials – for example rapeseeds or sunflower seeds – go through several coordinated processing steps.

First, the raw materials are cleaned, crushed and, depending on the process, gently heated. The heat helps to open the oil-containing cells more effectively, making the subsequent mechanical pressing more efficient. Since a considerable proportion of oil usually remains in the press cake, many manufacturers use what is known as solvent extraction in a further step.

Hexane in oil extraction: what is behind it?

The most commonly used solvent in industrial plant oil extraction is hexane. Hexane is an organic solvent that can dissolve oil particularly efficiently from oil-rich seeds and press residues. This makes it possible to significantly increase the yield compared with purely mechanical pressing.

After extraction, the hexane is technically removed completely and recovered. In the European Union, the use of extraction solvents is subject to legal requirements; the European Food Safety Authority (EFSA) regularly assesses their safety. Cold-pressed oils generally do without this processing step – this is an essential characteristic that distinguishes them from industrially produced oils.

Refining: what happens after extraction?

The crude oil obtained after pressing and extraction is usually further refined. Refining is a multi-step process in which undesirable accompanying substances are removed. The aim is to produce a stable, mild and neutral-tasting oil that is suitable for a wide range of uses.

The most important refining steps at a glance:

• Degumming: Certain accompanying substances such as phospholipids are removed.
• Neutralization: Free fatty acids are reduced, which improves shelf life.
• Bleaching: The oil is lightened; certain pigments are removed.
• Deodorization: Undesirable odor and flavor substances are removed under heat and vacuum.

Refined oils are particularly versatile and very stable thanks to this process. However, intensive processing means that part of the original aroma as well as certain natural accompanying substances that were still present in the crude oil are lost.

Cold pressing: gentle extraction with character

In cold pressing, the oil is obtained exclusively by mechanical means. The raw materials are pressed without the use of solvents or strong heat. The aim is to process them as gently as possible in order to preserve the natural character of the raw material.

After pressing, the extracted oil is usually only filtered or clarified by sedimentation – in other words, by allowing suspended particles to settle naturally. This preserves many natural components that are largely responsible for color, smell and taste.

Did you know? Cold-pressed oils often have a more intense aroma than refined oils. This is because natural plant compounds are largely retained through gentle processing.

Rapeseed oil: the most widely used edible oil in Europe

Rapeseed oil is the most commonly used edible oil in Germany and Europe. This is mainly due to its versatility: refined rapeseed oil is light in color, mild in taste and almost neutral in aroma. It is ideal for frying, baking and steaming – wherever the oil’s own flavor should not dominate.

Rapeseed oil is one of the oils explicitly recommended by the German Nutrition Society (DGE). The DGE advises giving preference to plant oils and names rapeseed oil as well as margarines made from it as particularly suitable choices. This is mainly due to its balanced fatty acid composition and its versatile use in the kitchen.

Cold-pressed rapeseed oil is a completely different experience. It has a golden-yellow to deep-yellow color and a pronounced, slightly nutty aroma. For this very reason, it is preferably used for salads, dressings, dips and cold dishes where its own flavor is meant to come through deliberately. Cold-pressed rapeseed oil is less suitable for frying at high temperatures, as the natural accompanying substances are more sensitive to heat.

Olive oil: the Mediterranean classic – obtained directly from the fruit

Olive oil occupies a special position among plant oils: unlike most other edible oils, it is not obtained from seeds, but directly from the fruit – the olive. High-quality extra virgin olive oil is produced exclusively by mechanical methods, without the use of solvents or refining.

The aroma of extra virgin olive oil is characteristic and versatile – depending on the olive variety and region of origin, it ranges from mild-fruity and buttery to strong-peppery and intensely grassy. The color varies between deep golden yellow and greenish yellow, depending on the harvest time and variety.

Refined olive oil, on the other hand, is significantly milder and more neutral in taste. It is used wherever the typical olive character should be less prominent – or where stability and a neutral aroma are required.

Argan oil: the liquid gold from Morocco

Argan oil is considered one of the rarest and most valuable plant oils in the world. It is obtained from the kernels of the argan tree (Argania spinosa), which is native exclusively to southwestern Morocco in the so-called Argan region – a UNESCO biosphere reserve.

Production is traditionally very labor-intensive: the hard-shelled fruits must be cracked open, the kernels carefully removed by hand and processed. For use as an edible oil, the argan kernels are often lightly roasted before pressing. This roasting process is responsible for the typical nutty, slightly smoky aroma that makes argan oil so distinctive.

Cold-pressed argan oil has an intense golden-yellow color and is valued both as an aromatic ingredient in the kitchen and traditionally in cosmetics. Anyone using argan oil for cooking is best advised to use it cold or lukewarm in order to preserve its delicate aroma.

Coconut oil: versatile plant oil with a tropical character

Coconut oil is a plant oil with a character all its own. It is obtained from the flesh of ripe coconuts and is widely used both in the kitchen and in body care. Depending on the production method, a distinction is mainly made between virgin coconut oil and refined coconut oil.

Virgin coconut oil is obtained particularly gently and therefore retains its typical coconut aroma. Refined coconut oil, on the other hand, is usually milder to almost odorless and is particularly suitable when a neutral oil is desired. The following applies to both variants: processing influences not only the taste, but also the character and area of use of the oil.

Coconut oil is often solid or semi-solid at room temperature and only becomes liquid at higher temperatures. This property makes it easy to measure in the kitchen and simple to use in many recipes. Coconut oil is especially popular for baked goods, Asian dishes, desserts and recipes where a subtle coconut flavor is expressly desired.

Those who choose coconut oil consciously usually pay attention to origin, production method and intended use. Especially when comparing virgin, cold-pressed and refined coconut oil, it becomes clear how strongly the type of processing can influence taste and sensory properties.

Cold-pressed or refined – which oil is suitable for what?

Both production methods have their place – they simply serve different purposes. The decision depends primarily on the intended use.

Refined oils are particularly stable, heat-resistant and neutral in taste. They are ideal for frying and baking at high temperatures as well as for all preparations where a neutral oil is desired. Cold-pressed oils, on the other hand, stand for gentler processing and a natural, original character. They bring significantly more of their own flavor and are often deliberately used as an aromatic ingredient – not just as a cooking medium, but as a flavor component of the dish.

Whether rapeseed oil, olive oil or argan oil: the type of production influences the taste, color, heat stability and overall character of an oil. Those who particularly value the natural origin of a plant oil therefore often consciously look for gentle extraction and high-quality raw materials.