Salting out LS?

[bitsquirrel]

My understanding is that salting out a lye-heavy sodium soap will get me a soap with (approximately) zero superfat, zero lye excess, and less (maybe no?) glycerol.

Has anyone here made lye-heavy LS and salted it out? I'm wondering if it's a way to get something with good storage qualities (a dryish solid, with no free fatty acids to go rancid, and some salt to keep microorganisms at bay) that I can dissolve in distilled water later to make LS. But maybe some unforeseen chemistry will happen. Am I running headlong towards snotsville?

 

[DeeAnna]

Table salt (sodium chloride) can be used to salt out a sodium soap (soap made with sodium hydroxide) without materially changing the soap itself.

Sodium soap + sodium chloride + water = sodium soap (insoluble) + sodium chloride + water

If you add sodium chloride to a potassium soap (soap made with potassium hydroxide), some of the potassium soap will become sodium soap, but not all. If you continue to add sodium chloride to this mixture, the sodium soap will become insoluble in the brine (salt water) and thus will salt out. The potassium soap in the mixture will remain soluble in the brine and will go down the drain when you rinse the solid soap curds.

Potassium soap + sodium chloride + water = potassium soap (soluble) + sodium soap (insoluble) + sodium chloride + potassium chloride + water

 

[bitsquirrel]

Thanks, DeeAnna.

So... curiosity got the better of me, and I did it anyway.

I now have a bottle of linseed oil soap that looks and feels identical to one that I bought, which I'm trying to replicate. I have no idea whether mine is sodium or potassium soap now, but if you're correct then it's sodium soap.

It's been diluted for a couple of hours and it's not snotty. How long does sodium soap usually take to turn snotty?

 

[DeeAnna]

"It's been diluted for a couple of hours and it's not snotty. How long does sodium soap usually take to turn snotty?"

If I understand what you mean by "snotty", the answer is I have no idea. I've never made linseed oil soap, so I don't have a clue what it's like, how it behaves as a potassium soap, or what you're going to get by adding salt.

"...if you're correct then it's sodium soap...."

You are misinterpreting what I said -- The soap is going to be a mixture of sodium and potassium soap molecules. You can't make a potassium soap and then expect it to obediently turn into an all-sodium soap just by adding some table salt.

 

[bitsquirrel]

You are misinterpreting what I said -- The soap is going to be a mixture of sodium and potassium soap molecules. You can't make a potassium soap and then expect it to obediently turn into an all-sodium soap just by adding some table salt.

But you said "The potassium soap in the mixture will remain soluble in the brine and will go down the drain when you rinse the solid soap curds."... Leaving me with sodium soap. Right?

 

[earlene]

So you did the whole salting out method by bowling boiling it in brine?

Edit (oops, meant boiling, not bowling.)

 

[bitsquirrel]

So you did the whole salting out method by bowling it in brine?

I started with linseed oil LS paste that zaps slightly. I diluted a heaping helping in a small pan of distilled water (I didn't measure stuff), threw in a handful of dishwasher salt, and heated it up for a couple of minutes. Then I let it cool for a while, until there was a creamy curd on top of clear brine.

I strained out the curd, discarded the brine (which was slightly tinted but showed no soapy tendencies), and tried to squeeze out as much water from the curd as possible. The amount of curd was comparable to the amount of paste that I started with.

I diluted the curd in hot distilled water. It diluted easily.

I'm comparing my soap to Ottosson linseed oil soap, e.g. https://www.linseedpaint.com/products/linseed-soap. Both soaps are somewhat turbid, with a slight pearlescence. The Ottosson soap smells cucumbery, mine smells faintly of ammonia, I do not know why. Mine produces more and bigger lather than the Ottosson soap, probably because it has no superfat. I've been playing with my soap all afternoon, and my hands feel only slightly dry.

At this point I do not know what I have created.

ETA: I think the smell is probably because I didn't wash out the shampoo bottle properly, and it's reacted with something. Oopsie.

 

[DeeAnna]

Okay, I'm following you now and stand corrected. I was focusing on the "adding salt to a KOH soap" part.

Yes, after going through the entire salting out process, the curd (solid) soap you recover will be largely sodium soap.

A sodium soap dissolved in an excess of water may become snotty or become a gel over time. It may become snotty or a gel and then revert back to a thin liquid eventually. Or vice versa.

It can take days to weeks to see what form the soap will take when it stabilizes. It depends on the fatty acid profile, the water %, and temperature, etc. There's no way to say what will happen with your particular situation.

 

[bitsquirrel]

Thanks, DeeAnna. I'll keep using it, and if it doesn't get weird I might try the same process starting with NaOH instead of KOH.

NaOH, linseed oil, distilled water and salt are all much easier to get hold of than KOH, phenolphthalein, citric acid and borax, so here's hoping.

 

[Susie]

What is dishwasher salt, and why would you add it to LS?

 

[earlene]

What is dishwasher salt, and why would you add it to LS?

https://en.wikipedia.org/wiki/Dishwasher_salt
https://fredsappliance.com/service/dishwasher-salt-use/

I had not heard that term before that I remember, either, so I looked it up.
Both links say it is 100% sodium chloride, so if that is the case, it should be fine to use for salting out soap.

But salting out LS is a concept I have not ever heard of before this thread.

 

[DeeAnna]

I wrote a tutorial that includes a couple of YouTube videos about salting out sodium soap scraps. Here: https://classicbells.com/soap/saltOutTut.html

 

[Zany_in_CO]

Has anyone here made lye-heavy LS and salted it out?

Hiya bitsquirrel!
Thanks for asking an interesting question.
I make linseed oil LS for washing wood floors, similar to Murphey's Oil Soap and flaxseed oil & rosin shampoo. Now I'm curious to see how a salted-out linseed oil paste would feel as a hand soap! Sure wish I had time to play!

@DeeAnna Thanks for your input.

 

[Savonette]

I wrote a tutorial that includes a couple of YouTube videos about salting out sodium soap scraps. Here: Soapy Stuff: Salting-out soap

Would you recommend re-batch or salt-out for soap that’s ugly (colors morphed badly) or grainy (soaped too low temp with stearic spots)?

 

[DeeAnna]

Either rebatch or salting-out will probably help grainy soap, as long as you get the soap fully melted. To remove some or all of an ugly color, you'd have to salt-out. Rebatch can't remove color. You could add color to a rebatched soap to a more pleasing shade, however.

I do not think soap is greatly improved by salting-out or rebatching. I've done both procedures enough to know how to do them, but I very seldom do either because it's a lot of work for not a lot of reward. I've seen a few people talk about rebatching 2 and even 3 times in an attempt to fix appearance issues, and I can't fathom why they want to do that.

I'd far rather use an ugly soap as-is -- it's all going to wash down the drain anyway, so it's not like I have to live with it forever.

As for stearic spots, it would depend. If the soap is so very gritty that it is unpleasant to feel, and I had my heart set on keeping the soap for whatever reason, well, okay, maybe I'd rebatch that soap. But if the stearic spots are pretty much a cosmetic issue, I'd use the soap as-is.

 

[Zany_in_CO]

At this point I do not know what I have created.

Firstly, thank you for going ahead and trying out your theory. I found it very interesting, although time and labor intensive and not necessary, to my mind at least, to duplicate the Ottosson linseed oil soap. I speak from the advantage of having done both, salted out NaOH soap and made linseed oil liquid soap. I'm a bit surprised at the copious lather... I wouldn't have expected that with linseed oil as a single-soap LS, but ya nevah know until you try! Good on ya!

What you have created is "pure soap" because that's the purpose of the salting out technique. I'm not surprised that it appears "turbid". If it is indeed NaOH soap with all the KOH bits washed down the drain, I'm guessing it will continue to coagulate further over time, just as when you dilute NaOh soap in water... it wants to become solid. If some of the KOH remains, you may luck out and it stays liquid.

My advice is to make another small batch of linseed oil soap paste using KOH.
12 oz of oils = 16 oz paste.
I would then divide the 16 oz. paste into 4 portions and experiment on how much water is needed to reach the perfect measure of soap to water.

Ratio Range: 40% soap to 60% water; all the way down to 15% soap to 85% water -- which may result in watery thin LS with good lather that you can thicken with brine -- similar to thickening castile LS.

BTW, you can avoid neutralizing with Borax or Citric Acid solution by soaping at (up to) 3% SF.

For a better understanding, you may want to read this thread about Zany's Flaxseed (aka Linseed) Shampoo

 

[Zany_in_CO]

Would you recommend re-batch or salt-out for soap that’s ugly (colors morphed badly) or grainy (soaped too low temp with stearic spots)?

Hiya Savonette! Your question is a good one. More people will see it and you should get more replies if you start a new thread.

 

[Savonette]

Either rebatch or salting-out will probably help grainy soap, as long as you get the soap fully melted. To remove some or all of an ugly color, you'd have to salt-out. Rebatch can't remove color. You could add color to a rebatched soap to a more pleasing shade, however.

I do not think soap is greatly improved by salting-out or rebatching. I've done both procedures enough to know how to do them, but I very seldom do either because it's a lot of work for not a lot of reward. I've seen a few people talk about rebatching 2 and even 3 times in an attempt to fix appearance issues, and I can't fathom why they want to do that.

I'd far rather use an ugly soap as-is -- it's all going to wash down the drain anyway, so it's not like I have to live with it forever.

As for stearic spots, it would depend. If the soap is so very gritty that it is unpleasant to feel, and I had my heart set on keeping the soap for whatever reason, well, okay, maybe I'd rebatch that soap. But if the stearic spots are pretty much a cosmetic issue, I'd use the soap as-is.

Thanks for this. I forgot about the third option - hiding it in the back of the cabinet!!!

 

[DeeAnna]

Firstly, thank you for going ahead and trying out your theory.

Bitsquirrel hasn't been here since their last post in this thread in 2019.