premixing lye...a warning

Soapmaking Forum - Soap & Candle Forums

Help Support Soapmaking Forum - Soap & Candle Forums:


Jul 4, 2008
Reaction score
This is something more experienced soapers surely know, but I thought I'd pass it on just in case.

Well, I tried to premix my 50% lye solution for the first time (ala Paul). I thought I'd be extra safe and just mix it right in the gallon bottle. Measure out my water in the bottle then slowly added the lye with a funnel. That way, I wouldn't have to transfer lye solution between containers, right? :roll: After I was done, I gave it a gentle shake (was worried that too much shaking might not be good and left it in the utility sink overnight to cool.

The next morning I made soap. I noticed it wasn't tracing nearly as quickly (or maybe not at all) but was glad it was that way after I put in the fragrance since I was planning to swirl the soap. Checked on it this morning...soap is super soft and has a bit of oil pooled in the bottom of the liner. This is when it dawned on me something was off with the lye. When I picked up the jug, I realized the lye had formed a brick on the bottom of the container. :DOH!: Guess the gentle shaking was not nearly enough to dissolve all the lye. No wonder my soap is so soft! Who knows what percent lye solution I really used. I can't believe I didn't notice it when I measured out the solution. Oh well, experiment and learn right?


Well-Known Member
Apr 21, 2008
Reaction score
Yep, I hate when that happens.

I premix lye, but I do 16oz of lye to 16oz liquid at a time. When completely dissolved and cooled enough (maybe 5 - 10 minutes) I pour it in the holding container. Then do it again, and again.

I try to mix about 10 lbs at a time. Easier in the long run.

It's a usual Sunday night thing at our house - "Stay out of the way, Mom's mixing lye - AGAIN"