About Lye Heavy Soap

lye heavy

I want to post this as what I consider a very important lesson in soap making. It relates to a couple of the current threads. It’s about lye and how lye works. Moisture “ruins” lye. We know that, right? What it does is deactivate it. First it weakens it and then at some point it is no longer of any strength to be called lye. It won’t make soap. (This is very rarely the reason for your failed soap and most likely to happen if you buy big buckets of lye.)

The same thing happens to the lye once you make soap out of it. If we have extra fat it’s superfat and if we have extra lye it’s” lye heavy”. But over time, that exposed lye will dissipate. Even if it’s on the inside of the soap, it is exposed to the soap which will have an effect on it.

When home made soap was the norm, if there was plenty of soap, the oldest soap was used for bodies and the newer soap was used for laundry and cleaning. This is why. The lye would dissipate over time making it milder. The first soap I ever made (and I’m not old enough for home made soap to have been the norm) was from a recipe that called for 6 pounds of grease and a can (13 oz) of lye. I forget how much water. The point is, it was not the science it is now. There was no “rebatching”. There was only waiting.

Now let me show you my accidental experiment. On March 13th of this year I made one of my standard soaps: grapefruit and clove. Very simple soap, 65% olive and 35% coconut with grapefruit and clove EOs. Somehow… I’m not sure how… it didn’t get mixed well but I didn’t realize. (Perhaps I was on drugs. Or perhaps I needed drugs) In any event, I cut this soap on my brand new Bud cutter and lye started running everywhere. In 40 years of making soap and cutting it with a knife, this happens on the second or third loaf after I buy the cutter,… but I digress.

I stacked and cured it as usual because I know that the soap teaches. It was a ruined batch of soap (40 bars) but it was a good lesson. Ruined soaps are always the best lessons. Where am I going to get a class in this for $35 (or whatever this mess cost me)?

The big ugly spots are lye. Yes they did zap. They zapped GOOD. About a month ago I checked them out and there was absolutely no zap on those big lye spots. They taste kind of ashy but they are not active and not dangerous. At the same time I cut into one and found the the center still zapped pretty good. Today I cut another one. You can’t see the cut bar clearly but it has streaks that look like the lye pockets on the outside. That still has a little zap to it but it’s more soapy tasting than just electric. It’s dissipating.

The little inset picture is of a bar of this soap that is how it’s supposed to be. I’ve been selling this exact soap recipe and scent for about 5 years. I’m still not sure how this happened but what I am sure of from this lesson is that if you are concerned that your soap might be a little lye heavy, don’t be. Don’t sell it, of course. Don’t use it yet (unless you are gloved and cleaning something nasty. Lye is great cleaner. The only time my stove top is truly clean is when I splash lye water.) Just wait it out. It will be fine.

I saved this soap to write this article. I am not going to sell or use this soap but I could if I just wait long enough.