Handcrafted soaps made from scratch require three things to become soap: oil, water and lye. They may have other ingredients to provide additional benefits, or to color or scent the soap.
The solid lye is mixed with water to dissolve it. The amount of water depends on the particular recipe, but is usually 2 to 3 times the amount of lye, based on weight. When the lye is added to the water the solution gets hot. It should be allowed to cool to room temperature before the soap is mixed.
The oils are then heated as necessary to melt any solid fats or butters. The final temperature of the melted oils should be between 80° – 110° F, depending on the recipe formulation.
Once the lye solution and oils are at the desired temperature, they are combined together and mixed. As mixing continues, the mixture will gradually thicken. It will also get warmer, sometimes quite hot, depending on the starting temperature.
Once the mixture has reached “trace” (the point at which miscture dribbled from a spoon will leave a brief trace on the surface), any other ingredients (scent, color, herbs, clays, etc) are added to the soap and thoroughly incorporated in.
At that point, the soap is ready to be poured into molds. The entire batch can be poured into one mold, to be cut up after it solidifies, or the soap can be poured into individual molds, depending on the preference of the soapmaker and the formulation of the soap. Once in the mold, the soap is left to cool and finish becoming soap. Often it is insulated in the mold to slow the cooling process.
Once the soap is completely cool and solid, it can be unmolded. If it was poured into one mold, this is the time to cut it into bars. The soap will be solid, but should be soft enough to cut.
The final stage is curing the soap for 3 – 8 weeks to allow the excess water to evaporate out. The length of time will depend on the temperature, relative humidity and air circulation where they are located. The soap can be used before then, but it will still be relatively soft.
Once the bars are sufficiently cured and hardened, they can be packaged as desired and, of course, used!
* “How Handcrafted Soap Is Made.” How Soap Is Made. Handcrafted Soapmakers Guild, Inc., n.d. Web. 03 Sept. 2012.