Uncovered lye solution; does it degrade?

[TheGecko]

Even a TL; DR answer doesn't work all that well if you're trying to convince a science-intolerant skeptic.

Or anyone who doesn't want to be wrong and/or who has already made up their mind.

 

[maxine289]

The science has been interesting (and is over my head), but what I'm really interested in is the impact of degraded lye solution on my batch of soap. I assume that by the lye solution absorbing water, the soap will be softer, take longer to cure and will have more super fat. Is that correct?

 

[shunt2011]

The science has been interesting (and is over my head), but what I'm really interested in is the impact of degraded lye solution on my batch of soap. I assume that by the lye solution absorbing water, the soap will be softer, take longer to cure and will have more super fat. Is that correct?

Yes, that’s the gist of it. It will be softer and have more of a SF.

 

[DeeAnna]

You pretty much nailed it.

 

[Peachy Clean Soap]

For all intents and purposes, all those facts and figures in Post 10 are just a TL; DR geeky way of saying the same advice I gave in my first post.

The short 'n sweet version --

Any lye solution for making soap will absorb water from the air unless the humidity is Mojave Desert dry.

Moving forward though I mix my lye for use as soon as its cool I'm gonna cover my lye & I'm mojave dry in this desert, wonderful scientific info.

 

[DeeAnna]

I recommend keeping some kind of cover on the lye solution at all times. When the solution is hot, only cover loosely so pressure doesn't build up, but cover it you should.

When the solution is steamy hot, a cover will reduce the amount of lye mist that escapes into the open air -- better for your lungs and better for your house.

A cover will also minimize the reaction with carbon dioxide in the air and reduce water absorption, both of which go on continuously, whether the lye solution is hot or cold.

 

[Peachy Clean Soap]

I recommend keeping some kind of cover on the lye solution at all times. When the solution is hot, only cover loosely so pressure doesn't build up, but cover it you should.

When the solution is steamy hot, a cover will reduce the amount of lye mist that escapes into the open air -- better for your lungs and better for your house.

A cover will also minimize the reaction with carbon dioxide in the air and reduce water absorption, both of which go on continuously, whether the lye solution is hot or cold.

Today I covered my lye & noticed I had less film on top of lye & dried powder on sides of bowl as it cooled & healthier lungs for the long haul its a win win. Thx for your help appreciate it.

 

[marehare]

Hi everyone, I searched the threads on this forum and didn't find the exact answer.

I am researching to respond to a specific FB post about uncovered lye solution. Aside from the obvious safety issue (who leaves lye water uncovered?? and why??), and water evaporation, can anyone provide a scientific answer as to whether the lye solution degrades when left uncovered for a couple of days?

Perhaps I was confused with the fact that dry lye crystals degrade and absorb moisture when exposed to air, but I was pretty sure I read that the liquid solution also degrades if not stored in an airtight container. I was thinking that I read this in Scientific Soapmaking, but have loaned my copy to someone and thus cannot check it. Thanks in advance for any help you can provide!

I mix my lye water solution for each individual batch and use it as soon as it cools to 120. I never premix it or leave it around. I wonder how you would use a cold batch of lye water when soap requires a hot mixture to mix with hot oils? How do you reheat it or do you use it cold?

 

[earlene]

It is not necessary to reheat the lye solution. When more liquid is added to the solution, it will heat up; not as much as when made from scratch, but enough to notice. Also when the lye solution is added to the oils, the reaction between the lye and the oils creates heat on its own without any added heat.

 

[AliOop]

I mix my lye water solution for each individual batch and use it as soon as it cools to 120. I never premix it or leave it around. I wonder how you would use a cold batch of lye water when soap requires a hot mixture to mix with hot oils? How do you reheat it or do you use it cold?

Hi @marehare

As @earlene noted, there is no problem adding cooled lye to warm or hot oils. It is an old wives' tale that the lye and oils need to be within 10 degrees of each other. Many people (including I) master batch a large quantity of lye solution ahead of time, so it is always cooled when we use it. It is not a problem unless the lye solution becomes cold enough for the lye to precipitate out of solution (approximately 65F). HTH!