Rancidity and Iodine Value

Working with the iodine value is a little more 'in-depth soap making/formulation' and you can be forgiven for totally ignoring this.

If you are using your soap as soon as you make it, and only making small quantities then it is unlikely that you will ever have a problem with soap going rancid.

But... I give you the information all the same... someone more technical than I could perhaps find it of value.

The iodine value of the oil that you use for making soap can be an indicator of a propensity to rancidity. The problem is that there are too many variables in the vegetable oil kingdom for there to be any hard and fast rules about this.

The iodine value is an indication of the amount of 'unsaturation' present in the particular soapmaking oil. The higher the unsaturated oil, in general, the more prone to rancidity BUT there are exceptions, so please don't take this as gospel!

Iodine Value Chart

Babassu oil = 15

Butterfat = 36.1

Canola = 110

Castor Oil = 85

Cocoa Butter = 36.5

Coconut Oil = 10.4

Cod-liver oil = 186

Corn Oil = 122.6

High-Oleic Sunflower = 90

Jojoba Oil = 84

Macadamia Oil = 75.5

Olive Oil = 81.1

Palm Kernel Oil = 37

Palm Oil = 54.2

Peanut Oil = 98

Rapeseed Oil = 98.6

Safflower Oil = 145

Sesame = 109.5

Soybean Oil = 130.5

Sunflower Seed Oil = 132.5

Sweet Almond Oil = 102

Tallow, beef = 45

Tallow, mutton = 40

Walnut Oil = 150

Wheat Germ Oil = 130

Aaagh! The iodine values are too much! Take me away from here!

Now before you draw a huge breath and exclaim "I saw TALLOW on that list! I don't want to use tallow!!" I need to explain, tallow has to be included as a natural ingredient... you really can't say it isn't. Most people whether vegetarian or not would prefer not to use it in their skincare products, however in the interests of sustainable living - and the future of our planet may depend upon this - it is a very useful ingredient that would otherwise be wasted. And, actually makes rather nice soap - no special skincare benefits but certainly nothing wrong with it.

I am not here to judge... it is up to you to decide what you consider ok to use or not.

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