Additives, Bases, & Lye

Our lye is sodium hydroxide, which is highly caustic and can cause skin and eye burns if handled improperly, but it's safe to work with when you follow standard precautions: wear safety goggles, chemical-resistant gloves, and long sleeves, and always work in a well-ventilated area. Once lye reacts fully with oils during saponification, it's converted into soap and is no longer caustic.

For more on handling, storage, and what to do if lye touches your skin, see our Lye Safety FAQ.

Adding water to lye can cause a violent, splattering reaction due to the intense heat released. Always add lye slowly to your water (not the reverse) while stirring gently, and mix in a well-ventilated space since the reaction produces strong fumes as it dissolves.

Soap bases (like melt and pour bases) are pre-made, ready-to-melt soap that doesn't require handling lye directly, making them a good starting point for beginners. Lye itself is only needed if you're making soap from scratch with raw oils (cold process or hot process).

Additives are ingredients you mix into a batch to adjust properties like lather, hardness, or skin feel, but not every additive is meant for soap. For example, polysorbate 80 is meant for bath bombs, where it helps colorants disperse evenly in water rather than float on the surface. Always check an additive's intended use before adding it to a project.

For a hands-on example of an exfoliating additive at work, see Making Pumice Soap on our blog.

Store lye in a tightly sealed, clearly labeled container in a cool, dry place, away from children, pets, and moisture. Lye readily absorbs moisture from the air, so keeping it sealed helps prevent clumping and maintains accuracy in your recipes.

Remove any contaminated clothing and immediately flush the affected area with plenty of cool water for at least 15 minutes. If it gets in your eyes, rinse continuously for 15 minutes and seek medical attention. Keep a readily accessible water source nearby any time you're working with lye.

For a real account of one maker's experience getting lye in her eye, including exactly what she did in the moment and afterward, read A Lesson in Sugar & Lye Safety on our blog.