Fats, oils, and their properties

The olive oil soap we made is a good basic soap, gives you a hard bar and lather enough. What if you want something more conditioning, or a better lather? This is where essential fatty acids (EFAs) come in. The different fats and vegetable oils are made up of different EFAs, so, while olive oil will give you that stable lather, hard bar, and conditioning, maybe you like more lather. You would then use an oil that produces it, has a good content of Lauric acid. If you want your soap more conditioning, you put in an oil fairly high in oleic acid. This is called balancing a recipe. When you look what you want in your soap, and produce those results manipulating oils.

When you make soap, it’s not just what oils you use, it’s how you use them.

Because it’s my blog, and I do olive oil based soaps, we’re going to start with a pound of olive oil. It has high percentages of oleic acid, which conditions, and palmitic acid, which produces a hard bar and stable lather. You’re going to want lather and a rinse clean feeling. We’ll use coconut for its lauric and myristic acids. Maybe you’d like to add a pampering feeling. Maybe 6 oz of corn oil for its linoleic and oleic acids, which give that clean feeling and conditions. To round this out, for its oleic acid, 2 oz of safflower oil. This is gonna be one sweet bar for a bath.

Now, let’s talk about superfatting. If we put all the oils together in the pot, then add the lye, you will have the superfat you discounted for. In my case, I’d still have the 5-8% superfat, but it’s the lye that decides how much of what is left unsaponified.

Every oil has a certain amount of unsaponifiables, parts that the lye won’t bond with no matter what. Some oils, our safflower up there, for instance, is high in unsaponifiables. These are the things that condition our skin. Because the safflower oil is higher in these conditioners, you may want to keep more of those molecules unsaponified.

Set aside your 2 oz of safflower oil. Mix the other oils, add the lye at the right temp, and stir to trace. When the mix thickens, saponification has started. The safflower oil is added then, mixed in with your scent, and then the soap is poured into the mold. Put it where it won’t be bothered. Leave it alone.

There are tables all over the internet with the oils and their respective traits. There are also a few books out with this and more information. Susan Miller Cavitch, The Soapmaker’s Companion is a good one.

Anything you study, it seems there’s always at least one noncomformist. Let’s talk about castor oil. Castor oil is about 90% ricinolic acid. This lathers, conditions, but it makes a very soft bar in large amounts. It’s also very humectant (absorbs water from the air). I make a shampoo for myself, bar shampoo. It’s almost a quarter castor oil, mostly because it can attract water from the air. That makes it good for hair, but not so good for storing. I store that one with packets of dessicant.

Castor oil will also take its own sweet time reacting with the lye. I’ve had a batch of soap with castor oil sit in the mold for a month. Usually, I hot process anything with castor oil because I don’t want to tie up my molds for so long.

Another quirk of castor oil is, the lower the iodine in the oil, the harder the bar. The ricinolic acid has to break that rule, too. Castor has a moderate amount of iodine, not high, not low, but it will produce a soft bar. This should really be a minority oil.

Anything with castor oil in it will cure very slowly. Even with hot processing, I often let bars with castor cure for 2-3 months. The soap has a much richer lather.

So, here we go, fats, oils, and their properties, fast and dirty:

Lauric Acid produces a hard bar, fluffy later. In high amounts, over 33%, can strip skin oils. Lauric is found in babassu oil, coconut oil, palm kernal oil, and tallow.

Myristic acid makes for a cleansing feeling, hard bar, fluffy lather, but won’t strip oils. Found in Babassu oil, coconut oil, and palm kernal oil.

Linoleic acid provides light conditioning and that rinse clean feeling. This is found in most oils, as is Oleic acid. Oleic acid provides conditioning. Your best bet for these is nut and seed oils. Mango butter, apricot kernal oil, sunflower and safflower oils, grapeseed.

Palmitic acid provides a hard bar and stable lather. This is found in most oils, but specifically apricot kernal oil, lard, cocoa butter, and tallow.

Ricinolic acid is only found in castor oil. It lathers, conditions, but makes a soft bar in large amounts.

And, finally, stearic acid. This makes for a hard bar and stable lather. Found in mango butter, shea butter, and tallow.

These lists are by no means complete. Do your own research for more information.

With all this in mind, let’s go make our soap.


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