Castor Oil: What Is It, What Does It Smell Like and How Long Does It Keep?

“Castor oil” turns up in recipes, forums and videos everywhere – in German it is simply called Rizinusöl. Hardly any plant oil is as thick or as distinctive. Here you will learn what castor oil is, how it is made, what it smells like, how long it keeps and what to look for when buying it.

Castor oil, ricinus oil, Rizinusöl: one oil, many names

Other names you may come across: ricinus oil, Ricinus communis Seed Oil (on ingredient lists) or, in German, Rizinusöl and Kastoröl. They all mean the same oil from the seeds of the castor bean plant.

What is castor oil and how is it made?

Castor oil is obtained from the seeds of the castor bean plant (Ricinus communis), a fast-growing plant of the spurge family. The bean-shaped, marbled seeds contain around 40–50 % oil.

For high-quality castor oil the seeds are cold-pressed – pressed mechanically, without chemical solvents – and the oil is then filtered. Good to know: the toxic protein ricin is found in the seeds but is not oil-soluble and stays in the press cake. Commercial castor oil does not contain it.

Chemically, castor oil is special: around 85–90 % of its fatty acids are ricinoleic acid, a fatty acid that hardly occurs in other plant oils. It is responsible for the oil’s high viscosity and unusual properties.

What does castor oil smell like?

Cold-pressed castor oil smells mild, slightly earthy to nutty – far more restrained than essential oils. Some describe the smell as slightly “oily” or waxy. A sharp, rancid or sour smell, on the other hand, shows that the oil is old or has been stored incorrectly.

Colour and texture: pale yellow to golden, clear and strikingly thick – it flows more like honey than cooking oil. This viscosity is not a flaw but typical.

How long does castor oil keep?

Thanks to its high ricinoleic acid content, castor oil is one of the more stable plant oils. As a rule of thumb for our oil:

• Unopened: about 2 years when stored cool and dark.
• After opening: use within about 12 months.

To extend shelf life, always close the bottle tightly and store it cool (not above room temperature) and protected from light – ideally in amber glass. More in our guide storing oils correctly.

What is castor oil used for?

Castor oil is a classic raw material for further processing. We expressly offer our castor oil as a pure plant oil raw material – not as a ready-to-use cosmetic product. Typical uses:

• As a carrier oil for your own fragrance blends with essential oils – on its own or mixed with thinner oils such as almond oil or jojoba oil.
• As a thickener in craft recipes, for example for soaps, candles and waxes.
• For leather and wood care blends – more in our guide wood care with essential oils.
• Technically: worldwide, castor oil is an important raw material for lubricants, paints and plastics.

Anyone who makes and passes on their own end product from castor oil is responsible for its formulation, safety assessment and labelling. You will find an overview of all carrier oils in our carrier oils category.

Buying castor oil: what to look for

• Cold-pressed rather than refined or solvent-extracted.
• Botanical name Ricinus communis on the label.
• 100 % pure – no additives, fragrances or preservatives.
• Light-protective packaging and a batch number for traceability.
• The right quantity: small bottles for occasional recipes, large containers if you process regularly.

Our castor oil is cold-pressed from the seeds of Ricinus communis, free of additives and hand-filled in Germany – from 100 ml to 5 litres.

Frequently asked questions about castor oil

What is castor oil called in German?
Rizinusöl – the oil from the seeds of the castor bean plant (Ricinus communis).

Why is castor oil so thick?
Because of its very high ricinoleic acid content, which gives it its honey-like viscosity.

Is castor oil toxic?
The toxic ricin is found in the seeds and stays in the press cake during pressing – it is not contained in the oil. Even so, our castor oil is not a food and not intended for consumption. Avoid contact with the eyes and keep out of reach of children.

Can castor oil go off?
Yes, like any plant oil it can turn rancid over time, which you will notice from a sharp or sour smell. Stored cool, dark and tightly closed, it keeps for a long time.

Can I mix castor oil with essential oils?
Yes, as a carrier oil for your own fragrance blends. Because it is so thick, many people mix it with a thinner base oil.

🌿 Casse-Q – Natural oils with character
Cold-pressed, free of additives, hand-filled in Germany: discover our castor oil and our other carrier oils.