There are more than 100 different species of oil-bearing crops. Only a dozen of them are actually being used on a large scale for cultivation to obtain their valuable oils. For more information see our ecological oil crops.

The characteristics of the oil obtained after extraction from the carrier (mostly the seeds or beans) varies greatly between the different species. Every oil consists of a mix of different fatty acids. A fatty acid is mainly built out of carbon and hydrogen atoms. The number of carbon atoms in a fatty acid molecule typically ranges from 12 to 22. Three fatty acids molecules are glued together with glycerol to form what we call an oil or fat molecule.

Another distinction between the fatty acids is what is called the level of saturation. The more saturated a fatty acid is, like the one on the picture above, the less reactive it becomes to, for example, oxygen or hydrogen. These are also more stable molecules. The chemistry behind this is the fact that a carbon atom can bond up to 4 atoms. In the case two carbon molecules are bond with two or a double link, the fatty acid bends and becomes unsaturated (see picture below). The double bond is vulnerable to a hydrogen attack. This process is used in the industry to create a hardened fat and it is called hydrogenation (e.g. margarine production). The fatty acid can have several double bonds and is also called polyunsaturated fat.

It is important to know that saturated fatty acids like palmitic, are solid at room temperature, whereas unsaturated oils like oleic are liquid at room temperature. If the oil is used as nutrition the (poly) unsaturated oils are proven to be healthier. The omega-3 fatty acid is a good example of this. For the use as a biofuel high levels of polyunsaturated fat are not favorable because the oxidation stability (biological degradation) is poor. The level of unsaturation in the oil is measured and expressed as the Iodine number.

We can describe the different types of oil also in their fatty acid composition profile. Usually we describe oil and fat in the ratio of saturated, monounsaturated and polyunsaturated fatty acids. It is also possible to describe the oil on basis of their relative molecule lengths or number of carbon atoms like C12 or C22. In this way we get more details. The common length for saturated fatty acids is C16 (palmitic) or C18 (stearic). For monounsaturated fatty acids or oleic acids the length is C18:1. Polyunsaturated fatty acids are mostly described as C18:2 or linoleic acids.

Some vegetable oils like rapeseed also contain erucic acid or C22.1, upto 40%. Erucic acid (Omega 9) as a nutrition is according to some studies beneficial to the cardiovascular system. Erucic acid is the fatty acid described in the movie Lorenzo’s oil as a neurobiological treatment for a neurological disorder.

Omega 9 fatty acids consist of C18:1 and C22.1. But also C20:1 and C24:1. Omega 6 consists of the following: C18:2, C20:2, C22:2. Omega 3 fatty acids are a family of acids from the group: C18:3, C20:3, C20:4 and C22:6. For a complete list you can go to this link. In general one can say that oils containing omega 3 and 9 are healthier than oils containing omega 6 alone. But there are many interactions between its metabolisms in the human body. In the bar graphic below the yellow represents the healthy oil component. Hemp and olive are among the healthiest oils.