Letter Re: How to Make Lye Soap

As a former soap company owner and operator, I enjoyed the article on soap making (How to Make Lye Soap, posted on November 30, 201.) However, for safety’s sake, I would like to caution your readers regarding some of the statements made in the article:

1. The author’s instructions say to “Heat the water to 110° F. Add the lye to the water.” This is a dangerous suggestion. The chemical reaction caused when lye combines with water causes even room temperature water to heat up almost to the boiling point. Starting with overly-warm water could (and probably would, depending on room temperature) cause the lye solution to literally boil—a potentially catastrophic occurrence. I always use room temperature (or colder) distilled water then, after sprinkling and stirring in the lye, allow the water to cool down to between 100 and 110 before combining it with the warmed oils.

2. The author also says that the lye water can be combined with the warmed oils in a blender. Although, technically, this is true (and I’m sure there are many experienced soap makers who use a blender), the batch of soap would need to be very small to stay within the blender’s capacity while operating. Most of us have had a blender accident at one time or another by either overfilling the blender or realizing (too late) that the lid wasn’t security in place. It’s one thing to have applesauce or a milkshake sprayed around the room, but toxic and dangerous lye water spraying around your kitchen (and on you) would be a scary scene, indeed. Personally, I would never use a blender for making soap. Instead, I use a stainless steel pot and either a wooden spoon or a stick blender (make sure the blades are stainless steel) to combine the lye water and oils.

3. Your readers need to be aware that each oil requires a different amount of lye to be turned into soap (a process called saponification). Some oils require more lye than others. Too little lye for the type of oils used means that the mixture won’t turn into soap; too much lye and you’ve got a hot (overly alkaline) bar of soap that can potentially hurt the skin of the ultimate user. Here’s an example of what I mean: One pound of olive oil requires approximately 2 ounces of lye to properly saponify; however, one pound of coconut oil requires nearly 3 ounces (suggested amounts can vary depending on the amount of water used in the recipe). The problem is magnified if you are making a larger batch (and really, making soap is messy enough that you’ll want to make larger batches). When it comes to lye, one size does not fit all. Fortunately, free lye calculators are available online from a number of web sites, including Majestic Mountain Sage, Brambleberry, and SoapCalc.

Soap making can be a rewarding and creative skill to master, but I encourage anyone who is interested in making soap to learn the basics by reading a good soap making book, such as The Soapmakers Companion by Susan Miller Cavitch or Soap Maker’s Workshop: The Art and Craft of Natural Homemade Soap by Robert S. McDaniel and Katherine J. McDaniel. By the way, Robert McDaniel is a scientist who explains not only what to do when making soap, but why.