Flakes in my lye solution

[Hermanam]

When mixing a 50:50 lye solution, I often get a thin crystallized film on top of the solution. Generally, I stir it back in and things seem okay.

Last night, I was preparing to make a small batch of soap when something came up. I had already mixed my 50:50 lye solution (I had planned on adding CM later). So, I just put my lye solution away in a safe place and saved it for this morning.

This morning, the crystallized layer on top seemed a bit thicker. When I stirred with a spoon, there are now little flakes floating througout the lye solution. I tried putting my lye container in a warm water bath, but that doesn't seem to be helping.

I have always bought my lye from BA, but the crystallization/flakes has happened on more than one occasion when I make a 50:50 solution.

Has anyone else encountered this issue? Is it okay to use? I am worried about lye pockets. I would really appreciate any thoughts or suggestons.

 

[Hermanam]

Forgot to ask...if I dump this solution and start over, how do I dispose of it? Is it okay to pour down the kitchen drain with running water?

 

[shunt2011]

I have that happen once it awhile, just strain it before adding it. I've never had a problem doing that.

 

[DeeAnna]

The flakes form when the NaOH in your lye solution reacts with carbon dioxide (CO2) in the air. The stronger the lye solution, the more likely and the faster this will happen. Also, the longer a lye solution sits, the more time the lye has to react with the air.

I personally would just strain the solution and use it for soap, unless we're talking about a thick heavy crust of stuff. That said, I can't see exactly what you are dealing with, so take this comment with a big grain of salt.

(For the benefit of others reading this, we're talking about "floaters" on top of the lye solution, not "sinkers". If you have stuff at the ~bottom~ of your lye solution, chances are good that your lye is not completely dissolved. In that case, stir more to get it 100% dissolved. When making a 50% lye solution, as the OP has done, the NaOH will not dissolve as quickly as it does with less concentrated solutions, so you have to stir longer and check carefully.)

"...Is it okay to pour down the kitchen drain with running water?..."

Yes -- good choice. This is the safest way to dispose of a lye solution short of using it in soap.

Pour in a thin stream and use plenty of ~cold~ water, not hot, as you pour. You want to dilute this a lot right away as it goes down the drain. (Why cold water? Because the lye solution is going to heat up as it mixes with the water.) Let the water run for a minute or two after you finish pouring the solution to flush the pipes.

 

[Hermanam]

DeeAnna, thanks for the explanation and advice. I get the "floaters" pretty consistently when I mix a 50% lye solution. When I stir them in, tiny little bits just seem to float around in the solution. I would eventually like to masterbatch a 50% lye solution in a recycled laundry soap jug. Do I need to be concerned that these floaters will cause a problem?

 

[judymoody]

It also may be that some evaporation took place (leaving your water amount effectively less than your lye amount) and your lye began to precipitate out of solution.

A 50/50 lye solution also may be compromised by lower temperatures. If it sat out over night and got cold, the water might not be able to dissolve that much lye.

Straining your solution is probably an adequate way to resolve the problem. You might also want to weigh your solution and then add back any missing water due to evaporation.

 

[Hermanam]

Cold may indeed be a factor, as my soaping area is in my basement. These days, it's pretty chilly down there. Will this cause problems with the quality of a materbatched lye solution? If I do masterbatch, I will definitely weigh it afterward and add any water back in to account for evaporation. Thanks to everyone for all the help.

 

[DeeAnna]

First off, I'd sure keep Judy's good advice in mind.

I normally loosely cover my solution mixing container when the lye solution is hot to minimize water loss from the solution. The key is to LOOSELY cover, not tightly cover -- you do not want to build up any pressure in the container. Just cover the open surface of the container so most of the evaporating water will condense and return to the solution rather than escape to the open room air.

I would also use a container for storage that is close to the size of your masterbatch solution. This will minimize the air space in the container and thus the amount of CO2 that the lye can react with over time. That said, I don't think you can eliminate the flakes, so plan to strain them out when you use the solution for soap making.

Another suggestion for masterbatching -- Some people use varying concentrations of lye solution for their soap making or they are making milk soaps and want to use a 50% lye solution plus the milk. in these cases, a 50% concentration makes some sense. If you normally use, say, a 33% lye solution for pretty much all of your soaping, a 50% masterbatch doesn't make as much sense. In that case, I would suggest that you make the lye solution at your usual concentration (40%, 33%, or whatever) and store that. Sure it will be a somewhat larger volume, but this might eliminate some of the issues involved with storing a near-saturated solution of NaOH.