The world of natural and handmade soaps can be very confusing. I remember when I was first introduced to the novel idea of making my own soap I had a hard time understand what all the terminology was about, and felt overwhelmed by all the different choices I came across. So to help those of you out who might be having just a hard as time as I did, here’s an explanation!
In the handmade soap world, there are three different kinds of hard bar soap you will come across. Each has their own benefits and weaknesses, and it really depends on what you as a customer (or a soapmaker!) wants in soap.
Glycerin Soap: Also known as “melt and pour” soap, this is the easiest of all the soap types to work with. Companies sell premade blocks of soap that can be melted down and poured into molds to create the desired look. Hence the “melt and pour” terminology! When the soap is melted down, additives such as extra oils, coloring, and fragrance can be added to create diversity and soap unique to the maker. This soap derives its name from the high glycerin content that is added during the manufacturing process to give it moisturizing capabilities. A drawback to glycerin soap is exactly this—its factory made. While its the easiest of the soap types to work with, its also the most processed and unnatural. Often times a handmade glycerin soap will have the same type of ingredients that store bought soap has—namely sulfate, stabilizers and hardeners. Poor quality glycerin soap is little more than a detergent bar, though some glycerin soap bases can be purchased with natural ingredients and without added sulfates. Glycerin soap is also very versatile, and can be combined with many other ingredients to create products like sugar scrubs and whipped soap creams.
Cold Process Soap: This is the soap process I use the most! Cold process soap is one of the more ancient forms of soap making, and takes advantage of the natural reaction between lye and oils. Water is added to lye to make an extremely basic pH solution. This is then added to the desired oils. The lye saponifies the fats, turning it into soap. Saponification is the process of turning the triglycerides in oils into glycerol and fatty acid salts. Soapmakers typically use a certain percentage more oils than required in their soaps, a process called “super fatting”, to ensure that all the lye introduced to the oils has been completely used up. This also allows for extra moisturizing capabilities of the soap as the extra oil will come into contact with skin and be absorbed. Cold Process Soap derives its name from the temperature the ingredients are mixed at, which is typically 90-110 Fahrenheit. Cold process soap makers allow the ingredients and time to drive the reaction to completeness. A downside of cold process soap is the long cure time. This type of soap must be allowed to cure for several weeks before useable. This allows moisture to escape the soap to harden and to ensure that the reaction is complete. However, this type of soap can be completely natural and totally handmade as they entire process is controlled by the soapmaker, unlike in glycerin soap.
Hot Process Soap: A cousin to cold process soap, and just as ancient, hot process soap is similar in that lye, water and oils are combined to make soap. They differ, however, in that temperature is increased in hot process soap to drive the reaction to completeness in a much quicker time frame. This results typically in a harder bar with a faster cure time (if any cure time at all!), but unstable oils, fragrances and colors sometimes have trouble with this method. It can lead to soap browning due to the high temperatures. There’s also a higher chance of a lye volcano if you’re not careful!
And that’s pretty much it for soap types!