I’m often asked if I use lye, or sodium hydroxide, in my Emmet Street Creations soap. The answer is yes. Yes, I do. If someone tries to sell you soap that wasn’t made with either sodium or potassium hydroxide, walk away or they may talk you into the snake oil they are selling as well.
The truth about soap is that it absolutely cannot be made without lye. The very definition of soap from the Google dictionary is, “a substance used with water for washing and cleaning, made of a compound of natural oils or fats with sodium hydroxide or another strong alkali, and typically having perfume and coloring added.” Occasionally I’ll see recipes on Pinterest for “No Lye Soap.” These recipes use melt and pour soap and while you don’t personally have to use lye to make this type of soap, it was actually created with lye to start with.
The follow-up question I’m usually asked is, “is lye safe?” Lye on its own is a very dangerous and caustic chemical capable of maiming, blinding or killing anyone who doesn’t give it the respect it deserves. As a soap maker, I use extreme caution and take many safety measures to ensure that I don’t harm myself when working with lye. I wear goggles, gloves, a face mask to filter the fumes, a long-sleeved shirt and long pants. I work very slowly and deliberately around lye water. Sometimes I imagine it’s a coiled cobra ready to strike if I make a wrong move. (I have an active imagination.)
But, here’s the thing: by the time a batch of properly formulated soap is complete and ready to use, the lye no longer exists in its original scary form. Through the magic of chemistry, in a process called saponification, the lye water reacts with the oils and creates a completely different substance… soap. Soap makers use complex mathematical equations to make sure they use they use enough lye to react with all the oil and even leave some oil behind to nourish your skin.
As a soapmaker, it’s important to make sure that each batch of soap is safe and does not contain too much lye. There are several methods to do this. We can test the pH by using pH test strips (or, apparently, red cabbage). We can even use our tongues. In a method called a “zap test” we touch our tongue to a bar of soap (one we don’t intend to sell to you, I promise). If we feel an unpleasant tingle on our tongue, we know the soap has some remaining lye and should not be used. I use both PH test strips and the zap test on my soaps to ensure they are safe and mild. I also use a bar from each batch (the one I licked, of course) on myself before I ever consider selling it to the public.
Do you have a question about the soap making process? Ask it in the comments or on our Facebook page and I’ll do my best to answer in a future post.