reheating lye

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Hello,

I'm just shooting from the seat of my pants here. I have never had to heat my lye solution in the microwave before and I don't think that I will ever have to. A lot of people think that lye is something a bit more dangerous than it really is. The only reason I wouldn’t want to put it in the microwave is because you may superheat the solution and end up just having to put it into a sink of cold water. I would just take it out a few hours before you'll need it and place it in a sink of warm water. It will liquefy in no time at all. Shoot, I'd like to put some frozen lye into the microwave tomorrow just to see, because you never know if you don't try.

Take care,
John
 
Soaps House said:
A lot of people think that lye is something a bit more dangerous than it really is.
Click to expand...

Lye isn't dangerous at all...
Soapmakers who don't have the necessary knowledge and respect for lye are what is dangerous.

Children and pets running around where lye is just minding it's own business are also dangerous.
 
xyxoxy said:
Soaps House said:
A lot of people think that lye is something a bit more dangerous than it really is.
Click to expand...

Lye isn't dangerous at all...
Soapmakers who don't have the necessary knowledge and respect for lye are what is dangerous.

Children and pets running around where lye is just minding it's own business are also dangerous.
Click to expand...

I agree with you 100%. I have done quite a bit of reading on it and I have no fear of my lye bucket blowing up in my face. If it were as bad as some believed you wouldn't be able to buy it so easily.

John
 
ycartf said:
Carebear, I have never had a problem with my Pyrex-like batter bowl (another brand) and I have mixed AND reheated in it over 40 times. I don't know if folks who have them shatter have caused/allowed sudden temperature changes like immersing in a sink of ice water while the lye mix was near boiling or what.

If not glass, what do you mix your lye water in? I tried plastic before and it appeared to take on a color as though it had dissolved a little of the plastic into the mix. I am not sure what metal/s could be repeatedly used for this without suffering damage from the repeated strong caustic exposure. What does everyone use then?
Click to expand...

Like xyxoxy said, the danger with mixing lye in glass is because of the etching issue. Lye solution etches glass over time, weakening it until one day it goes KABOOM! And since one can't ever predict when that shattering day will come, mixing lye in glass is a lot like playing Russian Roulette.

Stainless steel is great and many soapers use it to mix their lye solution in. Stay away from anything with aluminum or tin, though. Those 2 are bad news.

Certain plastics are good, too, but not all plastics are made alike. There are some you should steer way clear of with lye solutions, like PETE #1 for instance. The lye solution will eat away at it, causing the plastic to leach into your solution; and with repeated use, within maybe a week or 2, it will eat a hole right through the container (ask me how I know! :shock: ). Also stay away from polycarbonate (the crystal clear-type Rubbermaid containers), nylon (polyamide) or polystyrene plastics. Acrylics are ok for very short term exposure, but not for repeated use or long term storage. The best plastics to use with lye are PP #5, and HDPE #2. They are both resistant to alkali and can withstand heat (PP #5 can withstand boiling water, and HDPE #2 can withstand temps to 190 degreesF). To find out what type of plastic container you have, look at the recycle # on the bottom of it.

Re: reheating lye. I do it all the time, but not in the microwave. I just fill up a small pan with hot water and stick my lye solution container into it, changing out the cooled-off water for more hot water as needed until my lye solution has warmed up enough.


IrishLass :)
 
Here's How I Reheat My Lye

I know this question is old but just in case someone is looking for a simple solution to reheating lye water, let me share how I do it.

Please note, I believe I can do this only because I use the same recipe all the time (it's for a basic laundry soap) and so I don't usually need to do too much calculation to readjust my measurements. If you need to do something like this for different types of fancy bathing soaps, I imagine you need to do a little more maths to arrive at the correct new measurement of lye pearls you need to add but it can be done, I think:

1. I divide the lye solution into two parts.
2. I add back the quantity of water removed (50%) to one part.
3. I add back half the quantity of lye (50%) that was in the original lye solution.
4. I stir and then allow the mixture to cool back to my desired temperature.
5. I store away the other half of my original lye solution for another day.

:bunny:
 
Why would you even want hot lye solution? As soon as you mix it with oils, it starts warming up anyway.

And IMHO, taking all the steps listed above completely removes all benefits of masterbatching lye and water anyway. You may as well just mix it fresh each time.
 
How I reheat lye:

Wearing goggles, mask & gloves, with a flat bowl to catch any spill overs, I nuke it in a Pyrex cup in the microwave for 10 seconds on #3 (Defrost). NOTE: Plastic container is not recommended for this process. It can melt and degrade into hot lye solution which makes it unuseable. Ask me how I know! :mrgreen:
 
Zany_in_CO said:
How I reheat lye:

Wearing goggles, mask & gloves, with a flat bowl to catch any spill overs, I nuke it in a Pyrex cup in the microwave for 10 seconds on #3 (Defrost). NOTE: Plastic container is not recommended for this process. It can melt and degrade into hot lye solution which makes it unuseable. Ask me how I know! :mrgreen:
Click to expand...

And using lye in the microwave can cause an explosion of the glass. Yep, had it happen with water not lye thank goodness. Personally, irresponsible to even suggest it.
 
Susie said:
Why would you even want hot lye solution?
Click to expand...

Good question, Susie. When making glycerin LS, I want my KOH solution to be 210°F (99°C) or higher before adding to my oils (160°F 71°C). I've learned from taking temps in early experiments that those are the temps that will allow me to successfully stick blend the batch through all the phases of becoming soap in 2 minutes (when using all KOH) or 5 minutes (when using 50/50 KOH/water).

I would not recommend this to everyone. Even experienced soapers should proceed with caution, as I do. I'm comfortable with handling lye safely and using a microwave. It's not something I do often -- just another tool in the soaping tool box to pull out when needed.

HTH :bunny:​


shunt2011 said:
And using lye in the microwave can cause an explosion of the glass. Yep, had it happen with water not lye thank goodness. Personally, irresponsible to even suggest it.
Click to expand...
Thank you for your valuable input, dear heart. :thumbup:
 
Gosh, I never thought that glass could be etched by lye. Good to know. Thus are thicker glass recipients still safe to use?
 
BaBa said:
Gosh, I never thought that glass could be etched by lye. Good to know. Thus are thicker glass recipients still safe to use?
Click to expand...
If you search the forum for Pyrex, you'll find quite the debate about using glass. I would weigh in on the no glass side of the discussion. For example, here's a thread that goes into a little detail:

http://www.soapmakingforum.com/showthread.php?t=23590
 
Zany_in_CO said:
Good question, Susie. When making glycerin LS, I want my KOH solution to be 210°F (99°C) or higher before adding to my oils (160°F 71°C). I've learned from taking temps in early experiments that those are the temps that will allow me to successfully stick blend the batch through all the phases of becoming soap in 2 minutes (when using all KOH) or 5 minutes (when using 50/50 KOH/water).

I would not recommend this to everyone. Even experienced soapers should proceed with caution, as I do. I'm comfortable with handling lye safely and using a microwave. It's not something I do often -- just another tool in the soaping tool box to pull out when needed.

HTH :bunny:
​
Click to expand...

I am also an experienced soaper. I am experienced enough, for example, to know that I can get the same results as an all glycerin soap using water as an equal weight to mix with the KOH, then mixing the remainder of the "water" amount as glycerin into my oils. And it does not require heating in the microwave to get paste in 2 minutes. It just requires a fresh mix of KOH/water and melted oils. How do I know this? I tested it. I step outside of the methods laid out in Catherine Failor's book, and test for myself. This, therefore, does not require reheating "lye", either in the microwave, or any other method.

It is very irresponsible to give that advice to newbie soap makers. How would you feel if they used your method, then had that Pyrex explode? I would feel horrible if I gave bad advice and something happened to someone.

Newbie soapers-please do not try Zany's method above. Pyrex can explode when heated in the microwave using water alone. It is much more dangerous when you have etched it repeatedly using lye.
 
Last edited:
Susie said:
Why would you even want hot lye solution? As soon as you mix it with oils, it starts warming up anyway.

And IMHO, taking all the steps listed above completely removes all benefits of masterbatching lye and water anyway. You may as well just mix it fresh each time.
Click to expand...


Hi Susie! Actually, I have a masterbatch sitting and I have been experiencing issues with false trace since I bought and used a stick blender for the first time (I know, primitive me :)). I read online that my soaping temperatures are the likely culprits so I wanted to take my temperatures a little higher -- lye and oils.
 
carebear said:
if your lye solution is cooler than your oils then you can get a false trace - essentially the lye solution contributes to the oils thickening and solidifying. So it's good, at least when starting out, to have lye and oils around the same temp.

I used to soap warm (say 100 - 110 deg) but went to soaping with lye and oils both cooled to about room temp to give myself more time. But now i've gone back to warm for many soaps as it helps ensure gel - plus i've very little patience. So with fos that will let me, i tend to soap warm again.
Click to expand...
Good Post.gif
​
 
MissE said:
Hi Susie! Actually, I have a masterbatch sitting and I have been experiencing issues with false trace since I bought and used a stick blender for the first time (I know, primitive me :)). I read online that my soaping temperatures are the likely culprits so I wanted to take my temperatures a little higher -- lye and oils.
Click to expand...

I would let the oils be a bit warmer rather than trying to heat the lye solution. Or, as I stated earlier, don't masterbatch and just use fresh hot/warm lye solution. There are solutions that do not involve heating lye solution, and they are much safer, not to mention easier. I used to let my hot lye solution melt my solid oils. Heat transference method. Ensured gel every time, not a false trace in the bunch. But you have to work fast, and don't stick blend too much. Otherwise you get a plop and pray.
 

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