Fatty Acids In Soap: What Do They Do?

Fats and oils are made up of fatty acids. Each oil possesses its own blend of fatty acids, called the fatty acid profile. Usually, we seek to make a bar with qualities that are well-balanced for bathing, which is the reason we mix several oils to take advantage of the dominant properties of each oil. We typically want a bar that is hard and long-lasting, but one that lathers well and cleans without being drying. Exceptions to this are not uncommon, but most would consider this to be the ideal.
The fatty acids we are concerned with for soap making are: lauric, myristic, palmitic, stearic, ricinoleic, oleic, linoleic and linolenic acids. Each brings properties to the process of soapmaking and the finished product. We will discuss one fatty acid per post.

The first two posts dealt with lauric and myristic acid, which make hard bars with copious lather, but also are cleansing enough to be drying and do not make a long-lasting bar. This post describes palmitic acid.

Palmitic acid is another saturated fatty acid. It provides us with a hard bar that lasts a long time. While it does not create lather, it does contribute creaminess and helps stabilize lather. Oils high in palmitic of the common soapmaking oils are palm, of course, and the animal fats. Shortening, made up of animal fats and or palm oil, will lend the same virtues to soap. Interestingly, Japan Wax is extremely high in palmitic acid, at 80%, according to www.soapcalc.net.

In addition, many butters also offer significant palmitic fatty acids—cocoa being the most common; but also red palm butter, mafura butter, mowrah and avocado.

Several oils, in addition, are high at 20% or higher in palmitic acid: coffee bean, palmolein, sea buckthorn, andiroba, ostrich and baobab among them.

These oils are often used alone or in a combination from 20 – 60% of a total formula.

Of course, no usage rate rule is actually a rule. Exceptions abound for a number of reasons; therefore, consider them guidelines only. Let experience and purpose guide the actual formula.

Stay tuned! The next blog post is all about stearic acid.

May your days be filled with bubbles and wax.

Beth Byrne, for Making Soap, Cosmetics & Candles