How old is too old for NaOH? Does lye "expire" as such?

[Primrose]

Someone on a fb group I'm in has just offered me lye (NaOH) that she hasnt used for about the last 18 months. I know it can absorb moisture from the air, but if its been sealed in a container is this likely to still be 'useable' lye, or will it be no good?

 

[KristaY]

I think it would still be fine but it would depend on the area she lives and the humidity. I have KOH I bought about 3 yrs ago it's perfectly fine but I live in a VERY dry area. When I received the bottles I weighed each and wrote that number on the bottle. Each time I take one out and check the weight, it's exactly same. I remember someone on SMF talked about using lye given to her that was a decade old and the soap came out dandy. If that person says the containers are unopened/sealed, I think you'll be fine.

 

[Primrose]

Thanks KristaY - I have asked how its been stored, the climate here is pretty much dry with slight humidity. Good to know it can be stored for long periods of time if stored correctly.

 

[SoaperForLife]

As long as it was properly stored it should be fine. I had some bulk lye sitting around for several years before it got used and I haven't had any problems.

 

[Lin19687]

I have a bucket of 10 year old lye. Some clumpy on the top. But lye doesn't go bad in general............. Yup that is going to get a heated debate but unless you left it out with no lid and it got solid.... It MAY be slightly degraded but after this debate on and off from the Dish I think you are good

Anyway, works fine under the clumps. I DID buy new this year to see if there was a difference and there is not.

it is humid here so I try not to open it when it's like that.

 

[DeeAnna]

Clumps in your NaOH granules are the result of the NaOH absorbing water. If you leave dry NaOH out in the air, it will clump and eventually even turn into a liquid because it can absorb that much water from the air. I videoed an informal demo to show this --



If you make an NaOH masterbatch solution and let the masterbatch solution sit for awhile, you may see a layer of fine white "mud" lying on the bottom of the solution. That's going to largely be sodium carbonate (washing soda) from the NaOH reacting with carbon dioxide in the air.

Of the two, water absorption is probably the worst and most obvious problem. If your NaOH granules are mostly loose and free flowing with some clumps that fall apart with a good shake, the NaOH is most likely fine to use. If the clumps are hard and large, the purity of the NaOH might be lower than you want for soapmaking.

 

[AKelly75]

I realize as a sporadic hobby soap-maker, my thoughts won't carry as much weight, but I have lye that is 15+ years old that I use on and off when the soapmaking bug hits me again. Until a few years ago, I didn't realize my lye might be considered too old. I had stored it in heavy duty plastic bags in a bin in my rather damp basement. Because I still have success with making my soap, I've left it there but have more recently been using a dehumidifier to keep the basement a little drier in the summer. Occasionally, I'll come across some chunks, which I just throw out.

 

[SoapAddict415]

I once got lye from a supplier on Amazon that I suspected was a return because the safety seal had been punctured. It was easier to keep it than return it. It looked fine but I suspect that it absorbed quite a bit of moisture because EVERY batch made with it ashed HEAVILY. I've never had batches ash that badly before or since. With this batch, some of the bars were completely covered when I unmolded them.

 

[Escott752]

I'm so glad you asked! Someone gifed me, the hobby soap maker, 50 lbs of lye I wasn't sure if it would keep!

 

[SoapAddict415]

I must've forgot to add the pic

 

[Lin19687]

I have never heard of lye causing ash.

I have an old AND mew pail of Lye and they both ash.

With a spray of Alcohol, with out the alcohol, all are covered when gelling and uncovered 2 hrs later.
Some get it, some don't.
I have yet to figure it out but I don't care, I embrace the ash

Here is a pic of 4 batches, all done the same way/recipe. They are boxed for FM transport.