Properties of the vegetable oils and butters that I use

Jojoba oil

Really a liquid wax, not an oil, this ingredient is purified from the large, acorn-like seeds of the desert-growing jojoba bush.  The composition of jojoba oil is similar to that of the oils on our skin, so in a super-fatted soap it will help replenish the skin’s oil balance.  It is also resists rancidity, so soaps containing jojoba oil will last longer than those based on other oils.

Cocoa butter

Although it is expensive (particularly when produced organically), I like to include cocoa butter in my soaps because it produces a rich lather and a very hard bar that will not melt away in the shower.  Plus, it smells super great!

Coconut oil

Like cocoa butter, coconut oil helps to produce a hard soap that resists rancidity.  It also contributes to the moisturizing and lathering qualities of the final bar.

Palm oil

Helps to speed up saponification, which is the chemical process that converts fats and oils into soap.  Also helps produce a longer-lasting lather, and contributes to the hardness of all-vegetable-oil soaps.

Olive oil

I include this oil because it is a good moisturizer and contributes to a mild soap.  High percentages of olive oil can result in a soft, quick-dissolving bar, though, so I keep the proportion low.

More information about vegetable soaps

Hardness

The harder the soap, the more it will resist melting away in a puddle of water by your sink or in the shower.  Highly saturated fats produce hard soaps, which is why soaps based on animal fats are so hard.  Most vegetable oils are not saturated, and so they make softer soaps – for example, non-industrial Castile soaps, which are predominantly olive oil, are much softer than tallow-based soaps.  To produce a hard bar, I include three relatively saturated vegetable oils – cocoa butter, coconut oil, and palm oil – in my recipes.  Aging the soap after production also helps to remove unreacted water and harden the bars; my soap is aged at least a month prior to being sold.  The aging step can be omitted by making hot-process soap; however, this can affect the properties of the oils.  All of my soap is made using the slower, milder cold-process method.

Mildness

Soaps are made when an acid (in this case, the vegetable oils) reacts with a base (lye) to form soap and glycerin.  My recipes are “superfatted,” meaning that there is extra oil left over following this saponification reaction.  This makes the bars rich, mild, and moisturizing.

Lather

The quality of the lather – large or small bubbles, long lasting or not – influences both the cleaning power of the soap and the pleasure felt when using it.  The palm oil and cocoa butter in my soap produce a long-lasting lather, while the coconut oil makes the lather rich and fluffy.

Freshness

Because they are mostly unsaturated, vegetable oils are particularly prone to rancidity; this is also true of soaps made from vegetable oils.  Superfatting also leaves the bars with unreacted oils that are susceptible to oxidation, which is what causes rancidity.  There are several anti-oxidants that can be added to soap, but I prefer to focus on modifying the ingredients rather than adding preservatives.  The more highly saturated vegetable oils (such as coconut, palm, jojoba) and butters (such as cocoa and shea) take longer to become rancid, so their addition in my recipes helps my soaps to last longer.  Many essential oils also protect against rancidity.  My soaps should last for over a year before starting to smell “off.”