What’s a cold process soap ?
I am often asked what’s the difference between handmade soaps and the ones you find on shelves, what can justify their costs. The difference comes mainly from the manufacturing method, as well as the ingredients.
The principle is simple, one mixes fat with a strong base (lye), a chemical reaction then occurs : the triglycerides (fatty acids) present in the oils and the butters interact with the lye which lead to the formation of soap and glycerin.
Oils (Fatty acid) + Lye → Soap + Glycerin
Once the mixture is done, the soap is poured into a mold to give it its final shape. It is unmolded 24 to 48 hours later sometimes more depending on the recipe. According to Kevin Dunn, professor in chemistry, and author of Scientific Soapmaking: The Chemistry of the Cold Process, the saponification is mostly done after 24 hours. But your soap is no ready yet, it’s time for a cure (4 to 6 weeks minimum)
The cure is a very important step that shouldn’t be skipped, during that time, the last remaining trace of lye saponify, the excess water evaporates, the soaps get dryer and harder (a harder bar tends to last longer), the lather become more stable. Basically this time of cure allows the soap to reach its full potential.
When we talk about handmade soap we also talk about superfat. Cold process soaps all contain an unsaponifiable part that is to say elements that have not reacted with the lye they give the soap beneficial effects to the skin (antioxidants, moisturizers, etc.).
A soapmaker can voluntarily decide to increase the percentage of superfat by adding more fat to the recipe is what is called superfatting.
The percentage of superfat is often indicated on the label but if it is not the case you can see it ( in the photos for example you will notice small white dots they are unsaponified fat) or feel it (the bar is a bit slippery).
The soapmakers who use this method of manufacture, choose their ingredients carefully to offer their customers a product of excellent quality. The formulations are often the result of months or even years of research. Buying a handmade soap is also a way to take care of your beauty and health while being green because the majority of those soaps are made with environmentally friendly ingredients.
If you want to learn more about soapmaking here a few books that I recommend that I bought for myself:
For beginners :
Anne-Marie Faiola : Pure Soapmaking: How to Create Nourishing, Natural Skin Care Soaps
Alicia Grosso : The Everything Soapmaking Book: Learn How to Make Soap at Home…
For advanced :
Kevin Dunn : Scientific Soapmaking: The Chemistry of the Cold Process