Ricinoleic Acid In Soapmaking

Fats and oils are made up of fatty acids. Each possesses its own unique blend. Usually, our goal is to make a bar well-balanced for bathing, and it is the reason we mix oils rather than using just one oil. We take advantage of the properties of each oil to create that ideal bar. A bar that is hard and long-lasting, but lathers well and cleans without drying the skin is the goal for most batches. Exceptions to this are not uncommon, but this is typical.

The fatty acids we are concerned with for soap making are: lauric, myristic, palmitic, stearic, ricinoleic, oleic, linoleic and linolenic acids. Each brings certain properties to the process of soapmaking and the finished product. We will discuss one fatty acid per post.

Previous posts dealt with lauric, myristic, palmitic and stearic acids.

Ricinoleic acid is perhaps the most interesting acid of all because of the oils, it is only found in castor oil. In fact, around 90% of castor oil is ricinoleic. None of the other oils contain it at all.

That alone is enough to make it fascinating; but what it does for soap is also interesting.

Ricinoleic acid traces quickly and creates a hard bar of conditioning soap. It not only
moisturizes, but is hygroscopic, meaning it draws moisture. Additionally, its viscosity helps to stabilize lather and assists oils high in myristic and lauric fatty acids create more, bigger bubbles. As if that was not enough, it also creates creamy lather. What’s not to like?

In truth, you would probably dislike castor oil in a single oil bar. It makes a thick, tacky, “lather” on its own that is rather unpleasant. The biggest surprise of all is that this soap makes not one bubble!

In a bar at even a small percentage however, it is a team player, adding the aforementioned qualities, whether used at 2% or up to 25% in special circumstances. Most soapmakers calculate well under 10% however, for a general bath bar.

If you have not tried castor oil in CP or HP soap, you may want to for your next batch.

Join us for our next fatty acid review, oleic acid.

Until next time, may your days be filled with bubbles and wax.
Beth Byrne, for Making Soap, Cosmetics & Candles Magazine
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