Soleselfie/ brine soap question

[Lye-h20-oil]

Hello, I'm working on a brine soap recipe and from what I understand, the correct way to calculate percentage of salt is to subtract the lye amount from the water amount then multiply by percentage x. My question is how much of the water is going to be designated for the salt to dissolve? Is it 100 % of the weight of salt? Also is a water discount recommended in a brine bar?

 

[amd]

I believe it is 27% max for salt, so when I do my brine bars I play it safe and calculate 20% to get the salt amount.
[using completely made up numbers for easy math] So if I need a total of 120g water, and 20g lye, I would subtract the lye amount from my calculation:
120 - 20 = 100g
And then calculate 20% of 100g to find my salt amount:
100 x .2 = 20g salt
I would still use 120g water total in the recipe.

 

[Carly B]

I just made a brine soap. I masterbatch my lye at 2:1, and in regular soap, use it as is. For this soap, I used 2.5:1. I took the "extra" .5 and dissolved the salt in that. Salt was about 25% of the water.

For this particular recipe with the masterbatched lye, I dissolved 1.5 oz of salt in 1.14 oz (32gm) of water. I stirred this into my premixed water/lye.

 

[Nona'sFarm]

For this particular recipe with the masterbatched lye, I dissolved 1.5 oz of salt in 1.14 oz (32gm) of water. I stirred this into my premixed water/lye.

So did all the salt dissolve?
Also, with a 2.5:1 water/lye, are you getting much ash?

 

[Carly B]

Yes, most of the salt dissolved. I used really hot water, which helped.

No ash yet. I made it last week, but they're creamy white (although they look pinkish in the picture), so it would be hard to see, wouldn't it?. I scented them with one of Nurture's discontinued, a dupe of Lush's Snowcake. Swirly bar mold and soap stone mold.

Here's a picture, along with my latest creation. Practicing with a soap stamp.

 

[Dawni]

I believe it is 27% max for salt, so when I do my brine bars I play it safe and calculate 20% to get the salt amount.
[using completely made up numbers for easy math] So if I need a total of 120g water, and 20g lye, I would subtract the lye amount from my calculation:
120 - 20 = 100g
And then calculate 20% of 100g to find my salt amount:
100 x .2 = 20g salt
I would still use 120g water total in the recipe.

What happens if you use more salt than that?

 

[Steve85569]

What happens if you use more salt than that?

The sodium hydroxide takes the water and the salt precipitates out of solution.
In simpler terms - you get salt crystals in your liquid and thus in your soap.

Sodium hydroxide has a stronger bond with the water than salt ( sodium chloride in this case) so it will use the water before the salt can. Sodium hydroxide needs a 1:1 ratio so the salt can only use the rest of the water in the recipe.
Clear as mud, right?

 

[Obsidian]

Seems like everyone is making it more complicated then necessary. I use 26% salt of water weight.
I've never subtracted the lye amount from the water before calculating the salt amount.

 

[MarnieSoapien]

Not to complicate the matter... but why such a high salt rate? From what I've read, salt water and brine have the same salinity, which is 3.5%. I have a feeling you all know something that I don't. Can someone please explain?

 

[Mobjack Bay]

Not to complicate the matter... but why such a high salt rate? From what I've read, salt water and brine have the same salinity, which is 3.5%. I have a feeling you all know something that I don't. Can someone please explain?

It’s possible to make a salt solution that has a much higher concentration of salt compared with sea water. (Fun fact: There are “hypersaline” lagoons along coastlines of some dry climate tropical areas). For example, at room temperature, 35 g of salt will dissolve in 100 g of water, resulting in a 26% salt concentration in 135 total weight of salt + water. It sounds like the others are saying that the addition of lye will force some of the salt out of solution if the lye is added to a fully saturated salt solution. Chemist needed from here, on

ETA: oops, re-read your question and you didn’t ask how, but why.

 

[Dawni]

Yes, thanks @Steve85569

Reason I asked is I think I've used more before and was wondering if something could be happening to my soap that I couldn't see lol....

I've never subtracted the lye amount from the water before calculating the salt amount.

Me neither....

 

[Mobjack Bay]

Yes, thanks @Steve85569

Reason I asked is I think I've used more before and was wondering if something could be happening to my soap that I couldn't see lol....

If the salt comes out of solution, would you end up with salt crystals in your soap... a “salt bar light”?

 

[Obsidian]

If the salt comes out of solution, would you end up with salt crystals in your soap... a “salt bar light”?

Not in my experience. Any salt that comes out of solution isn't in crystal form like table salt. Its more of little soft flakes that either get blended up or are so fine, you just don't notice them in the soap.

 

[amd]

Seems like everyone is making it more complicated then necessary. I use 26% salt of water weight.
I've never subtracted the lye amount from the water before calculating the salt amount.

I only do it this way (calculating water not used by lye) because the first brine batch I made I didn't do the math and had (as another member called it) a "light" salt bar. Not what I wanted in a brine bar and my dry skin found it to be too harsh. My skin seems to prefer the salt fully dissolved. And it really isn't that complicated, it's two math equations - or one if you simplify the process by premixing a larger batch of salt water, using regular water to make a 1:1 lye solution and then add the remainder water with your premade salt water.

Not to complicate the matter... but why such a high salt rate?

Because we can? LOL. There really isn't a good reason to or not to, the preference is up to the maker. You can make it fully saturated (with salt) or not as saturated. I tried my second batch with a 20% saturation - fully intending to try various percentages in different batches, I tend to start at the max and work my way down - and I liked it, so no further experiments done. Well... unless you count my semi-failed batches of Zany's no slime castile, which I think is about 3% salt.

 

[cmzaha]

Not in my experience. Any salt that comes out of solution isn't in crystal form like table salt. Its more of little soft flakes that either get blended up or are so fine, you just don't notice them in the soap.

When I make mine, any that fall out of solution gets dumped in the soap pot. Afterall I love salt bars so I just do not get picky. A few salt flakes do not bother me since they are not hard and abrasive. If you do not want them in your soap you could strain them out.

 

[Mobjack Bay]

What SF are y’all using for a brine bar?

 

[Carly B]

I just used the 5% default on SoapCalc. I don't think I've used a different SF on any soaps I've made.

 

[amd]

What SF are y’all using for a brine bar?

I use 7-9%.

Just to note for the sake of documenting my experiments:
My first successful batches I made with 7% SF and slightly modified my regular recipe from CO 18% to CO 28%. Quite lovely in hot sticky summer months but not so much in dry winter months. My last batches were 9% SF and my regular recipe (18% CO and includes 20% butters). I couldn't tell a difference in lather between the two recipes, but I could feel the cleansing difference. Not sure if it was the change in SF or lowering the CO or the combination of both, but the the higher SF with lower CO is more pleasing for my skin year round.

 

[Dawni]

I guess my recipe works because of the climate here? 35% coconut oil and 7% superfat (in the calc)

Edited to clarify:
I always use half ACV for the liquid which adds about 3.6% superfat so my total is closer to 10-11% SF, with 35% coconut oil, and 30% salt dissolved in the ACV

 

[Lye-h20-oil]

Thank you all, love this forum! Soap turned out great.