Some Important Terms In Making Bar Soaps

In today’s post, I want to talk about some of the common terms used in making bar soaps. This is to make sure we all have a clear understanding of what each of them means.

Saponification: It is the chemical process of making soap that involves an exothermic reaction between lye (sodium hydroxide) and a fat (usually oils). What is commonly known as cold process soap making yields a glycerin-rich soap, which used to be referred to as lye soap. People often think of lye soap as a soap that is unpleasant to use because too much lye was used in the soap formula and lye (sodium hydroxide) remained in the bar of soap to irritate and burn the skin. Soap cannot be made without using lye. When made correctly, no lye will remain in the bar of soap.

Saponification Value: Today, with easy access to the exact composition of a fat and the molecular weight of a fat, it is easy to determine the exact amount of lye needed to completely saponify a measured amount of a specific fat, so there will not be any extra lye in the soap and the soap will not irritate the skin. The number of milligrams of lye (sodium hydroxide) required to completely saponify one gram of a specific fat is referred to as the saponification value. Note: Laboratories usually refer to the saponification value of potassium hydroxide, not sodium hydroxide. Potassium hydroxide is commonly used to make liquid soap and sodium hydroxide is necessary for making solid bars of soap.

Seizing:  This happens when something in your recipe has gone horribly wrong, and your trace happens so fast that if you can somehow glop the soap into your mold, you will have to press it into your mold.  This effect is also called soap on a stick.

Trace:  This is the stage in the process of soapmaking when the soap looks like a thick custard.  Your soap can go from trace to solid in about 30 seconds after a good trace has been achieved.  So, it is important to add your herbs and fragrances at a very light trace, so I have plenty of time to pour.

Gel:  This is a stage that the soap goes through after it has been poured into the mold.  The soap in the center of your mold becomes dark and gel like, if you touched it you would see that it is in fact gel.  It is not necessary for your soap to go through gel, but in happens frequently.  The gel stage is a product of the chemical reaction between the oils and lye.