Pre made lye got lumps...!

[HCee]

Made some lye last week, cooled it down and stored in an old HDPE 2 fabric conditioner bottle.

I've just looked at it and there's a crust on the bottom where it's gone solid again (much like if you were to boil sugar and cool it)

I've searched the threads and can't find anyone else with this problem.

I weighed 50/50 water & caustic soda.

Any suggestions please?

 

[DeeAnna]

Some ideas --

Low purity NaOH with a high proportion of sodium carbonate. The sodium carbonate will not fully dissolve and will form a layer in the bottom that can be stirred up, like sand in a pail of water.

You mis-measured and have more NaOH in the water than can dissolve.

The NaOH was not stirred long enough to get it fully dissolved.

The NaOH solution is too cold, and some of the NaOH has crystallized into the solid layer.

 

[Guspuppy]

Some ideas --

The NaOH solution is too cold, and some of the NaOH has crystallized into the solid layer.

If the NaOH is too cold and it crystallized, does it need to be reheated to make soap? I had this happen today myself, the lye water was made yesterday and sat ~20 hours in my 58F basement. I went ahead and used it after stirring, and ~1 tsp bits were in the strainer after I added it to the oils.

 

[DeeAnna]

Unless you want to risk the chance of solid lye bits in your soap (if a person doesn't strain) or a higher superfat than you might like (if a person does strain), it would be a good idea to get all of the NaOH back into solution. You can do that by letting the solution warm back up, but you'll also need to break up and stir the solid bits as well -- it will take a loooong time to dissolve if you don't.

When this happened to me, I ended up adding extra water to the NaOH solution to get the solid NaOH to dissolve faster. This works pretty well but adding more water messes with the lye concentration, so you can't add water willy-nilly.

I weighed the water I added and I weighed the final NaOH solution after the solid bits were re-dissolved. The difference between the two weights was the 50% solution I started with. Knowing that, I was able to recalculate the lye concentration and use the solution to make soap.​

​

If you're not a mathy type person, this might be intimidating and you might just want to stick to the method of warming the solution and stirring.​

My rule of thumb -- If you need to store concentrated lye solution (in other words, any lye solution for making soap), keep it in a place that stays at 65F / 18C or warmer. Speaking from experience, preventing this problem is far, far less hassle than fixing it.

 

[HCee]

Some ideas --

Low purity NaOH with a high proportion of sodium carbonate. The sodium carbonate will not fully dissolve and will form a layer in the bottom that can be stirred up, like sand in a pail of water.

You mis-measured and have more NaOH in the water than can dissolve.

The NaOH was not stirred long enough to get it fully dissolved.

The NaOH solution is too cold, and some of the NaOH has crystallized into the solid layer.

Thanks very much for the reply.

Not had a problem with the brand of caustic soda before so I'm hoping to rule that out. It's also not sand like, it's more like a layer as if sugar had cooled.

Measured twice to be sure. I had the scales the draining board part of the sink so I double checked in case it was sat in the ridges - but of course that might mean it was measured wrong twice! I'm trying to get better at eyeballing amounts or everything so that if something was really off I'd notice before it was too late. I make sure I take a good look at ingredients before adding them.

Was definitely fully dissolved before I poured it in the container.

So I think then - it must be the room its stored in. I kept it in the utility room with no heating on in there and even though it's not cold at the moment (Im in the UK) it might have dropped below 18. Luckily I didn't make up too much so I'll warm it up and use it. Will only be a small batch so if there's something badly wrong I might be able to rescue it.

Thanks for the advice

 

[cmzaha]

How thick a layer on the bottom? Many times I would get a small amount of hardened on the bottom of my gallon containers where a small amount fell out of solution, at least I assumed that was the issue since I did not weigh my 2 gallons of hot lye then reweigh after it cooled to added in the extra water that may have evaporated. No way was I going to try and weigh a two-gallon bucket of hot or cold lye solution. I would lightly cover my bucket while cooling so it would build up a small amount of condensation. What would be left in my jug did not cover the bottom of the jug, less than a 1/4 and was not a thick layer. If it covered the bottom I would try to dissolve it or start over.

 

[TheGecko]

Made some lye last week, cooled it down and stored in an old HDPE 2 fabric conditioner bottle.

This could be the issue. I master batch my lye and I bought 2 brand new 1-gal jugs. I then rinsed them with hot distilled water and left them upside down to dry. I then make up my lye solution, stirring until it is completely clear, then allowed it to cool for a couple of hours and then pour into the jugs. The jugs are then stored in my soaping cart that is in the kitchen. Since no one gets into my cart, it's the safest place and they stay a pretty consistent temp of about 75F.

 

[HCee]

How thick a layer on the bottom? Many times I would get a small amount of hardened on the bottom of my gallon containers where a small amount fell out of solution, at least I assumed that was the issue since I did not weigh my 2 gallons of hot lye then reweigh after it cooled to added in the extra water that may have evaporated. No way was I going to try and weigh a two-gallon bucket of hot or cold lye solution. I would lightly cover my bucket while cooling so it would build up a small amount of condensation. What would be left in my jug did not cover the bottom of the jug, less than a 1/4 and was not a thick layer. If it covered the bottom I would try to dissolve it or start over.

Just about a 1mm line. I moved the container to somewhere warmer & it's gone back to liquid now, so I think as DeeAnna said, it was in a room too cold. I just had no idea it could re-crystalise! Every day is a school day

 

[earlene]

When making my master batch lye I add an extra 5 or 6 grams of water to compensate for evaporation. That is based on my experience with weighing the amount I normally make each time and weighing it after mixing. The amount that evaporated was always quite consistent.

Just mentioning this because depending on how big your masterbatch was, some water loss will occur through evaporation while stirring. If it's a significant amount (for me it hasn't been, but I don't make more than about 2000 grams of masterbatch at once) if could also contribute to this problem.

Recently I made masterbatch lye while traveling and stored the bottles in an insulated container, in hopes that it would not get too cold (or too hot, for that matter, but I was headed North) while being transported in the trunk of my car. If you have such insulation, it might be worth using for short term storage in your utility room, but not long term as the cold will eventually cool the insulation as well, making it more like a refrigerator.