There’s one question that every soapmaker eventually gets asked: “Does this have lye in it?” The honest answer is yes. And no.
Perhaps an explanation is in order …

All true soap is made with either Potassium Hydroxide or Sodium Hydroxide (depending on whether it’s a liquid or a bar), known commonly as lye. No lye, no soap; it’s part of the definition, as set forth by the Food and Drug Administration.

There are commercial products available that seem to be soap that don’t contain lye, but in truth, they are not actually soap. They are often labeled “beauty bars,” “facial bars,” or something similar. Again, true soap must be made with lye.

So, that covers the ‘yes’ part of the answer. What about the ‘no’?
Lye is used in the manufacturing of soap. However, if the soap is properly made, there is no lye left in the final product. The lye combines with a liquid (usually water) and some oils and/or fats and then undergoes a chemical process called saponification. In chemistry terms, an acid (the oil or fat) is combined with a base (the lye) to produce a salt (the soap). Yes, soap is chemically considered a salt!

If the recipe used is a good one, and the ingredients were measured properly, all the lye is used in the chemical reaction, so no lye remains in the finished product. This is why some soapmakers say that their soaps don’t contain lye.

What exactly is lye?

Many people think of lye as an acid, because it is highly caustic and potentially dangerous, however, it is actually a base. Historically, it was made by leaching ashes; today it is commercially produced to provide a consistent, stable product.

It has many uses, some of which may surprise you. Most people probably know that lye is commonly used in drain cleaners. But it’s also used in food preparation! It is often used to make olives less bitter, in canned mandarin oranges, hominy, several Asian foods, and most popularly in the United States – those big, yummy, soft pretzels!

If you want to make your own soap, but are afraid of lye, there are two solutions: The first is to educate yourself about lye safety, and then all follow the precautions, working slowly and methodically. The second solution is to use a technique called ‘melt and pour.’

With ‘melt and pour’ soap, you use a commercially available product that serves as a base for your soapy creations. You simply melt the product, add whatever coloring, fragrances, and additives you’d like (within the proper guidelines, of course!), and pour it into a mold. You never have to touch the lye, because someone else did it for you! While this is not handmade soap (I refer to it as ‘handcrafted’), it is a legitimate creative expression.

Whichever method of dealing with lye you choose remember that lye is something to respect; with proper safety practices, there’s no need to be afraid of it.

Also remember that while all soap is made with lye, none remains in a properly prepared final product.

You can enjoy handmade and handcrafted soap with confidence now that you know the truth about lye.