Lye, or sodium hydroxide, is a crucial ingredient in cold process soap making. The cold process is a method of soap making where oils and fats are mixed with an alkaline solution (lye) to create soap through the process of saponification. Here are the main reasons why lye is used in cold process soap making:
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Saponification: Lye reacts with the oils and fats in the soap recipe through a chemical process called saponification. This reaction produces soap and glycerin. Without lye, there would be no saponification, and soap wouldn't form.
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pH Adjustment: Lye is used to adjust the pH of the soap mixture. The saponification process initially produces a highly alkaline soap mixture. Over time, as the soap cures, the pH levels decrease and the soap becomes milder. The precise amount of lye used in the soap recipe helps control the final pH of the soap.
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Glycerin Formation: In addition to soap, the saponification process yields glycerin, a humectant that attracts and retains moisture. Glycerin is beneficial for the skin, as it helps to keep it hydrated. Cold process soap retains glycerin, making it a moisturizing soap.
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Control over Ingredients: When making soap from scratch, using lye allows soap makers to have control over the ingredients in their soap. They can choose the oils and fats they want to include, as well as any additives for fragrance or texture.
It's important to note that while lye is necessary in the soap-making process, the final product does not contain lye. Through saponification, lye reacts with oils and fats to form soap and glycerin, leaving behind a safe and effective product for cleansing. Proper safety precautions must be taken when working with lye, as it is a caustic substance, but when used correctly, it transforms into soap through the chemical reactions that occur during the soap-making process.
