What's the Difference Between Cold Process and Hot Process Soap?

The use of soap to wash our hands and bodies is an important component of our daily lives. Now, more than ever before, it has become a critical component of our daily lives! Like with the foods we eat, it is still very important to understand the ingredients being used in the soaps we are using on our bodies and the process that is being used to create these soaps. Soap is typically made using 2 different processes: Cold process and hot process.

Cold process soapmaking is the method most often used by soap makers who make soap from scratch. It's referred to as the "cold" process because no additional heat is added during the soapmaking process. However, the process itself does generate heat.

In hot process soapmaking, additional heat is applied to the soap mixture. The chemical reaction is the same but occurs faster than in cold process soapmaking due to the addition of heat. The heat also causes the finished soap to feel smoother to the touch. The hardness of the bar again depends on the selection of oils, the amount of water used in the process, and the length of time allowed for water to evaporate out of the finished bar.

Natural and Better for the Environment

Cold Process soap is made by combining oils, butters, and sodium hydroxide lye. These ingredients cause a chemical reaction called saponification. The fatty acids of the oils are broken down by the lye. During this process, the oils, scents, colorants, and other ingredients are selected and added.

Cold Process Soap has no added detergents which strip the skin of its natural oils. It is made through a chemical reaction between lye, sodium hydroxide, and oils. Cold process soaps are better for the environment, healthier for the skin, and can be very moisturizing.

The cold process requires a long curing process of up to 4 or more weeks to neutralize the lye. This time period helps to complete the saponification process, during which fats, water, and lye turn into soap. The longer the soap sits, the harder and milder it becomes.

Cold process soaps maintain the benefits of their ingredients. Cold process soap benefits the skin by penetrating deep into the skin. It cleans the skin on a very deep level and moisturizes the deep pores of your skin.

Is Lathering Up Healthy?

Many people like to lather up when using soap. But all that lathering may not be good for you. Commercial soaps that are sold in various stores are often made with chemical detergents, hardeners, and synthetic lathering agents. However, handmade cold process soap, created with oils, liquid, and lye does not contain harsh ingredients and still qualifies as soap. Handmade soap preserves the beneficial qualities of the oils, fats, and butters as the nutrients are retained in the soap making process.

How Cold Process Soap is Made

When starting the cold process soaps, the lye is weighed in a heatproof container. And the water is weighed in a separate container. The lye is carefully poured into the water, stirring gently until the lye has fully dissolved. The lye and water are then set aside and allowed to cool at room temperature.

While the lye solution cools, oils and solid butters are weighed and melted until about 100 degrees. The lye solution is poured into the container of oils or solid butters. These are stirred until ‘trace’ is reached. Trace refers to the point at which the oils and lye solution have emulsified. At this stage, there are no streaks of oil and the soap has a batter consistency. Any extra ingredients such as natural exfoliants or colorants are added at this time and stirred to combine the ingredients.

Pouring Molds

Melted soaps are poured into the molds. The soap is still caustic at this stage so safety gear should remain on while the soap is being handled. The molds are covered with a sheet of paper. To retain heat, towels are wrapped around the molds. They are set aside for up to two days to completely cool and become solid.

When ready, the soap is removed from the mold and slides into bars. The bars cure in the open air for at least four to six weeks before using.

Caring for your Handmade Natural Soaps

Soap bars have the potential to last a long time. The trick is to keep them as dry as possible between uses. Water breaks down your soap bar. Keeping them in the direct stream of your shower, as many people do, will shorten their life. Store soap outside of the shower on a soap dish, ideally with holes, to let them dry out in between uses.