Does lye lose potency over time?

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narnia

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I have a friend who had bought a case of lye 2 years ago, thinking that she was going into the soap making biz but after a couple of soap making fails, put it aside. She wants to give it another go, but is wondering if this lye is still good to use?
 

topofmurrayhill

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I have a friend who had bought a case of lye 2 years ago, thinking that she was going into the soap making biz but after a couple of soap making fails, put it aside. She wants to give it another go, but is wondering if this lye is still good to use?
Probably not. Lye loses its purity pretty quickly from exposure to air and humidity.
 

KristaY

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It depends on what environment she lives in. If it's very humid, it's probably absorbed moisture. If it's very dry, it might be okay. It also depends on how it was stored. Personally, I'd make a l lb test batch to see how it turns out but I live in a very arid climate so crazy high humidity isn't an issue for me.
 

lsg

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Lye will attract moisture unless it is in a tightly sealed container. I have had to flush a couple of containers of lye down the drain with lots of water, over the years, because it was bad. I buy lye in 2 lb containers and keep those containers in a sealed plastic storage bag.
 

narnia

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She lives in hot and humid Georgia.

She has opened only one container, so can humidity still get into sealed containers?
 

lsg

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She lives in hot and humid Georgia.

She has opened only one container, so can humidity still get into sealed containers?
If they are not sealed tightly enough, yes.
 

narnia

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Wow...I guess lye is one thing you should not buy in bulk!
 

IrishLass

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Right here, silly!
If it was stored properly in a dry place, it might still be good. I've used 7-year old lye that I had stored away high and dry, and it was perfectly good when I went to soap with it. I should mention that I live in a very dry climate.


IrishLass :)
 

shunt2011

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As long as it's stored properly I agree with IL. I'm using lye that's almost 2 years old. With no issues. I purchased 64 lbs.
 

Susie

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She can weigh each container. It should weigh whatever the lye weight is supposed to be plus the weight of an empty container. If she bought the lye at Essential Depot, the empty 2 lb container weighs 5.5 oz.
 

narnia

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Thanks everyone! I will pass on the info!
 

topofmurrayhill

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She lives in hot and humid Georgia.

She has opened only one container, so can humidity still get into sealed containers?
That is a good question. Plastic is porous, so there is some exchange with outside air. Many people mention humidity, but that isn't the only issue. NaOH turns into sodium carbonate (washing soda) on exposure to CO2 in the air.

Ideally, the answer would come from testing the lye. The information for doing that is in Scientific Soapmaking, by Kevin Dunn. But personally after 2 years I'd just buy fresh lye.
 

Misschief

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Hmmm... well, the lye I got from my mom over 10 years ago shouldn't have worked well but............... it worked just fine. It was in a 3 kg plastic bottle with a screw top cap. I'm not sure how long she had it but my soaps have turned out just fine. For what it's worth, we lived in the British Columbia Lower Mainland, at the edge of the Pacific rain coast.
 

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