Does Lye go bad?

[JPicasso]

It doesn't make sense that it would, but I had a strange experience last night and I want to get a read on it....

Have not made soap in a couple of years, but I have all my ingredients in a big tote, and stored in my basement. When I measured the lye, it was normal, small crystals with minimal clumping. However, when I mixed with water and set to the side, it settled to the bottom of the container, and formed a hard crust on the bottom. I had to go in and bust it up and used the stick blender on it to get it fully blended. (was extra careful to cover with tea towel so no splashing)
Anyways, I've not made more than a couple handfuls of soap batches, and never saw that before. Is this bad lye, or just bad mixing initially?

Soap seems okay, but it went to trace very quickly.

 

[DeeAnna]

You can't just dump NaOH crystals into the water-based liquid and walk away. They can and will clump. Stir immediately until most or all of the crystals are dissolved. That goes double if you're using cold liquid or even ice, rather than room temperature liquid.

The soap going to trace quickly isn't due to "bad" NaOH. It wouldn't saponify at all if the NaOH was degraded. My guess is too much stick blending or hard whisking, ingredients that were too warm, older fats with higher free fatty acid content, or additives such as fragrance or sugars that accelerate saponification.

NaOH and KOH don't "go bad" simply due to time passing. They go bad when they react with carbon dioxide and water vapor in the open air. The best way to know if the NaOH is okay is whether it flows freely or is in clumps. Small clumps that break apart fairly easily are a warning, but the NaOH is probably okay. Clumps that can't be broken apart are a sign of serious trouble.

Another rough indicator of NaOH purity is to measure the temperature of an NaOH mixture immediately after NaOH is dissolved in room temperature water. A 33% or higher lye concentration should reach at least 180F / 82C if not hotter. When I made an NaOH mixture at 50% lye concentration awhile back, the mixture reached 216F / 102C. Key things: measure the temp right after the NaOH is dissolved and use room temp water, not cold water and not ice, to make the mixture.

More info in my article: https://classicbells.com/soap/lyePurity.asp

 

[JPicasso]

Yeah, that makes sense.
I thought I stirred it well enough, but apparently I did not. And yes, I used some ice cubes, so that is good to know.

I think my end mixture was too hot, that explains the rapid setup.

Thanks for the sanity check, my next batch should be back to normal.

 

[Hope Elisabeth 68]

You can't just dump NaOH crystals into the water-based liquid and walk away. They can and will clump. Stir immediately until most or all of the crystals are dissolved. That goes double if you're using cold liquid or even ice, rather than room temperature liquid.

The soap going to trace quickly isn't due to "bad" NaOH. It wouldn't saponify at all if the NaOH was degraded. My guess is too much stick blending or hard whisking, ingredients that were too warm, older fats with higher free fatty acid content, or additives such as fragrance or sugars that accelerate saponification.

NaOH and KOH don't "go bad" simply due to time passing. They go bad when they react with carbon dioxide and water vapor in the open air. The best way to know if the NaOH is okay is whether it flows freely or is in clumps. Small clumps that break apart fairly easily are a warning, but the NaOH is probably okay. Clumps that can't be broken apart are a sign of serious trouble.

Another rough indicator of NaOH purity is to measure the temperature of an NaOH mixture immediately after NaOH is dissolved in room temperature water. A 33% or higher lye concentration should reach at least 180F / 82C if not hotter. When I made an NaOH mixture at 50% lye concentration awhile back, the mixture reached 216F / 102C. Key things: measure the temp right after the NaOH is dissolved and use room temp water, not cold water and not ice, to make the mixture.

More info in my article: https://classicbells.com/soap/lyePurity.asp

Hey! Doesn't the lye water boil at some point? Mine got close to 200 recently and I quickly emerged the pain ice water bc I was scared it would boil.

 

[DeeAnna]

Hey! Doesn't the lye water boil at some point? Mine got close to 200 recently and I quickly emerged the pain ice water bc I was scared it would boil.

Hey! Don't assume a concentrated lye solution behaves the same way as plain water! Your NaOH solution was nowhere close to boiling.

A 30% lye solution (30 g NaOH mixed with 70 g water) will boil at approximately 118C / 244F. That's 32 degrees F hotter than boiling water.

A 50% lye solution will boil about 145C / 293F. That's 81 degrees F hotter than boiling water.

Another fun fact: An open container of water will lose weight to the open air due to the water evaporating from the container. An open container of any concentrated NaOH solution -- any lye solution you would use to make soap -- will GAIN weight by absorbing water from the open air.