Additives & Lyes

Lye, or sodium hydroxide, is the ingredient that turns oils into soap through a reaction called saponification. Without it you cannot make true cold-process or hot-process soap. You mix the lye with water, combine that with your oils, and the reaction produces a solid cleansing bar as it cures.

Raw sodium hydroxide is caustic and can burn skin and eyes, so it must be handled with goggles, gloves, covered skin, and good ventilation. Handled correctly it is used safely by soapmakers every day. Importantly, once soap has fully saponified and cured, the lye is completely used up and the finished bar is safe on skin.

Always add the lye to the water, never water to the lye. Adding water to dry lye can trigger a violent, eruptive reaction. Use cold distilled water in a heat-safe stainless steel or sturdy plastic container, add the lye slowly while stirring, and avoid breathing the fumes.

Flakes and pellets are the same chemical, sodium hydroxide, in two physical forms. Both dissolve into a lye solution and work the same way for soap making and pH adjustment. The choice usually comes down to handling preference and how easily each dissolves and measures for you.

Borax is a mineral additive used as a mild cleaning booster, a natural emulsion helper in some traditional creams, and a pH adjuster. It raises the pH of a formula and can help stabilize certain emulsions. Follow the use guidance on the listing, since the right amount depends on what you are making.

Boric acid is a mild antiseptic and pH-balancing agent used in some cosmetic and cleaning formulations. In cosmetics it appears at low levels as a pH adjuster and mild preservative booster. Because use levels and regional rules vary, follow the listing and any applicable local regulations for your finished product.

Yes. During saponification the lye reacts with the oils and is fully consumed, so a properly made and cured bar of soap contains no free lye. The caution applies to handling the raw sodium hydroxide while you make the soap, not to the finished, cured product.