Cold Process Method

 

Cold Process Soaping

The cold process method of soap-making is the traditional method of soap-making using all raw ingredients from scratch. The main difference in techniques is that cold process soap-making uses Lye, which is pretty nasty until it is disarmed through the saponification process.

Saponification is the chemical process where fats or oils react with a strong base (like lye) to produce soap and glycerin, essentially turning fats into soap. It's a type of hydrolysis where water breaks down the fat, resulting in a salt (the soap) and an alcohol (glycerin), making it fundamental to soapmaking.

Saponification, the chemical reaction turning oils and lye into soap, usually finishes within 24 to 48 hours, meaning the mixture is no longer caustic and is technically safe to use. However, soap then needs a longer 4-6 week cure time (or longer for certain recipes like castile soap) for water to evaporate, making the bar harder, longer-lasting, and milder. Heat speeds up saponification, while high water content or certain oils (like olive oil) can slow it down.

Cold process soapmaking blends oils/fats with a sodium hydroxide (lye) solution at low temperatures over 24–48 hours in the mold. This method allows for high customization, creamy textures, and intricate designs, requiring a 4–6 week cure time for a hard, gentle bar. Safety gear is essential due to lye as it is very corrosive.

 

*Some components of essential oils saponify or alter during saponification, which can change the scent of the essential oil. Most essential oils continue to evaporate as the soap cures, too. Thus more is needed to offer a nice scent, making EO soaps rather expensive to make.