Fats and oils are made up of fatty acids, each a unique blend. Usually, our goal is to create a well-balanced bar for general bathing, and it is the reason we mix oils rather than making soap with just one oil. We take advantage of the properties of several oils in search of that ideal bar, one that is hard and long-lasting, but that lathers well and cleans without drying the skin. Knowing what each of the fatty acids adds to soap is key to creating the bar you want.
The fatty acids we consider in 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, stearic, ricinoleic and oleic acids. If you missed them, just click on the links to catch up.
Soapmakers know of linoleic acid as the one that adds conditioning and moisturizing properties to soap and lends a luxurious silkiness, as well. Many of the high linoleic oils are chock full of the much sought after Omega 6’s. Sounds wonderful, does it not? It is!
Of course, linoleic also has a downside when it comes to soap. All of that luxurious moisturizing will also cause rancidity and DOS if calculated in high percentages. Furthermore, soaps high in linoleic fatty acid take longer to harden before unmolding and cutting. Most soapmakers therefore, cap oils high in linoleic at around 15%.
This decadent goodness also translates to a short shelf life, so consider adding mixed tocopherals or ROE to the oil to retard rancidity and keep it refrigerated or frozen until use. Plan to make soap with it within six months unless freezing.
Which oils are high in linoleic fatty acid? Evening Primrose Oil leads the pack at 80%, but low oleic safflower and low oleic sunflower follow closely behind. Other more common oils include grapeseed, walnut, hemp, wheat germ and cottonseed oil, along with more exotic oils such as passion fruit seed oil, poppy seed, black cumin, raspberry seed and watermelon seed. They sound luscious, and they are, but only if used quickly or in moderation.
Next blog post: linolenic 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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