There are several different methods for making soaps. I focus on two kinds: melt and pour and cold processed. Each type has several different properties and skin loving qualities! Let’s start with melt and pour.
Melt and pour is the process of melting a preexisting soap base, most often adding color and fragrance or essential oil, then pouring the soap base into a mold. Once the soap is cooled and is firmly hardened, the result is a bar that can be use right away. The benefits of melt and pour soap is not having to handle lye, sharp colors can be achieved, fragrances are more stable, no curing time, and kid friendly. The negative part of using melt and pour is that since it doesn’t cure it won’t last as long in the shower as cold process would. Also, because of the high glycerin content, in humid conditions the bars may tend to create glycerin dew. There is nothing wrong with the soap once it dews, it just doesn’t have the crisp appearance that it used to. Because melt and pour is relatively easy to use it is more widely used as a designer or novelty soap.
Cold process soap is mixing fixed oils with lye. A chemical reaction takes place that is called saponification. This is where the composition of the oils changes due to the introduction of the lye to create soap. Colorants and fragrances are added and then the “batter” is poured into molds, allowed to cool for 24-72 hours, cut, and cured. The soap bars must cure for 4-6 weeks in order for the soap to become mild and to harden. The benefits of cold processed soap are that you can use any blend of fixed oils and butters that can be specially formulated for individual skin types. Cold process soap bars are harder and last longer than melt and pour. A downfall is that due to the chemical process, there are serious safety considerations to take in to account when using lye. Not all fragrances, essential oils, and colorants survive in cold process, thus limiting design options. Curing time of 4-6 weeks also means that you must be patient and not immediately rewarded with a final product.
I enjoy both soaping with both types of soap but if I had to pick a favorite it would be cold process, hands down. I love chemistry! There are many steps in making cold process soap beyond adding lye water to oils and butters. Each base oil and butter has a different requirement for the amount of lye needed to make the conversion from fat to soap. This is the saponification value. Every time you alter a recipe or change an oil you have to recalculate the proper lye and water ratio. Then you must emulsify your lye and oils until you reach a certain stage called “trace” which is when the “raw soap batter” is ready to accept color and fragrance and ready to pour into molds. Once in molds you can regulate the temperature of the raw soap to make the colors look shiny, translucent, sharp, bold, pastel, light, or dark. This temperature phase is called Gel Phase.
The most exciting part of soaping is after the initial 24-72 hour cool down. The loaf is released from the mold and is ready to cut. Each slice of the loaf reveals a new and exciting edge of the soap. The soap could be used at this point; it is a ready soap product but it would be very soft and harsh on the skin. As the soap cures its pH balance softens from alkaline to neutral and hardens. An interesting side note on curing: some discoloration occurs with certain fragrances. Vanilla based scents react with lye and discolors brown. There are other fragrances that will discolor to a very pretty purple.
I could go on, and on, and on about soap. It has quickly become a topic that I love to discuss and can sometimes bore people with. I appreciate you taking the time to read more about one of my favorite subjects. Even more, I appreciate you enjoying the fruits of my labor! Try my soaps and you will see the love I put into each and every bar!