Drying out lye?

dreamscout · Mar 27, 2014

Since lye is hygroscopic, what can you do if your lye absorbs too much water?

I don't believe in throwing things away so originally I was thinking of mixing with distilled water, then calculating the amount of lye per oz of solution by measuring the PH of the solution.

But then I was thinking... could I just dry it out in the oven?

Anyone have any experience with this?

dixiedragon · Mar 27, 2014

Have you tried soaping with it?

lsg · Mar 28, 2014

Your lye may not be any good if it absorbed water. Try soaping an 8 oz batch to see if it works.

Susie · Mar 28, 2014

The problem I see is that unless you weighed that container before it absorbed moisture, you would never know when you got it back to the original weight. Therefore, you would be forever soaping with an unknown quantity of lye. You might be up for that, but not me.

I live in a very humid environment. I Ziploc bag my lyes while they are still in their original containers. If I slow down soaping, I will buy some of those moisture absorbant packs and throw those into the bags.

dreamscout · Mar 29, 2014

Susie said:
The problem I see is that unless you weighed that container before it absorbed moisture, you would never know when you got it back to the original weight

I hope that's not necessary. Anyone know how hot you need to get NaOH for it to become anhydrous sodium oxide?

Hypothetically if I could turn the over-moistened lye in to sodium oxide I could just adjust the measurement based on the molar mass of each, yeah?

That method should be pretty precise, but seems like it could be overkill if I could just use a temp high enough to evaporate the water but low enough not to catalyze the 2NaOH -> Na2O+H2O reaction.

Sounds like this might be uncharted territory. I'll let you guys know what I figure out, I suppose.

Nevada · Jul 2, 2017

3 bottles of Lye stored for 2 years. 3051g of lye gained 8g. Probably within margin of error. Nevada is so dry.

Susie said:
The problem I see is that unless you weighed that container before it absorbed moisture, you would never know when you got it back to the original weight. Therefore, you would be forever soaping with an unknown quantity of lye. You might be up for that, but not me.

I live in a very humid environment. I Ziploc bag my lyes while they are still in their original containers. If I slow down soaping, I will buy some of those moisture absorbant packs and throw those into the bags.

BrewerGeorge · Jul 2, 2017

The problem is that drying would not be the only reaction going on. You'd also be making washing soda via CO2 absorption, and at an accelerated rate at higher temps.