Lye water at room temperature

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Oct 25, 2022
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Canada, BC
I'm just wondering about lye water temperature? If we are supposed to keep are lye water with in 10 degrees of are hot oils why are some people on line using their lye water at room temperature? Is it because they are soaping at room temperature or at a cooler temperature? I thought it might be bad to soap at room temperature because of false trace. Also wondering if you can use lye water at room temperature, can you mix the lye and water ahead of time or the day before and leave it sitting at room temperature to use later?
You got it right on all points.

Your lye and oils can both be at room temperature, as long as your hard oils are still fluid and clear at that temp.

"Within 10 degrees" is more of a guideline than a rule. And different people prefer to soap at different temps. Hot oils can sometimes speed up trace where cooler temps can slow it down a little. Some people don't even melt their hard oils beforehand and let the chemical reaction do it for them (heat transfer method).

Lye solution can be made ahead. Just be sure it's in the right kind of container, close it up tight, and keep it in a safe place where no one is going to get into it.
I often masterbatch my lye solution and my oil mixture -- basically I make a quadruple my recipe. So I routinely use my lye solution at room temp. I do heat up my oil mixture.
Even when I make a single batch, I wait until the lye pitcher and the oil pot are just warm to the touch.
The real goal when starting a batch of soap is not the temperature of the ingredients before they're mixed; it's the starting temperature of the soap batter, which is the temp of the fats plus the lye solution right when the ingredients are first blended together.

The rule about having the starting ingredients within 10 degrees rule is mainly to keep beginners out of trouble, in my opinion. it's easy to see if your starting ingredients are all about 100 F, then the starting temp of the batter should be about 100 F as well.

But a more experienced soap maker can mix lye solution at room temp with fats at a somewhat warmer temp and end up with that same starting batter temp of 100 F.

I routinely mix room temp lye solution with fats that are around 105 F and get a starting batter temp of 95 to 100 F. That's about right for the way I make soap.
I never measure temperature and make my lye and let cool, sometimes I don't get time to make soap the same day and make it a few days later. I just melt the hard oils, add to the liquid oils, then add the lye. It's so much easier than measuring temps.

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