What Is Soap Made Of?

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The three basic ingredients of a typical soap are water, oil and an alkaline solution commonly referred to as lye. Oils that are used can be derived from vegetable or non-vegetable sources. Vegetable sources include rice, coconuts, ground nuts and castor oil plants. Non-vegetable sources include tallow and lard. Soaps also contain ingredients that add color or scent, but they aren't part of the chemical process of soap creation.

Two types of oil are used in soaps: base and specialty. Base oils include those derived from vegetable and non-vegetable sources, but not petroleum-based ones, which can’t be used during the soap-making process. Modern soaps normally use an oil blend of soy, olive and palm kernel oils. Specialty oils are used in addition to the base type; these include oils created from apricot, avocado, almond and jojoba seeds. Specialty oils also include butters such as mango, cocoa and shea butters.

Lye is a crucial ingredient because soaps are created through its interaction with oils. Lye comes in two types: sodium hydroxide and potassium hydroxide. The former is used in the creation of solid soaps, whereas the latter is used to make liquid ones. A combination of both leads to cream soaps.

A typical soap derives its scent from fragrance and plant-based essential oils. Fragrance oils are the result of combining aromatic chemical compounds. Pigments and mica are used to add color to a soap. Cinnamon, paprika and French green clay are examples of specialty ingredients that lend the soaps brown, orange and green color, respectively.