Pickles brine instead water

[sososo]

Yesterday I have made soap using pickles brine instead water.
The recipe is:
lard=33%
pomace oo=56%
coconut=7%
castor=4%
sf=3%
2 teaspoon sugar for 1200g of oils
lye/"water"=1/2

Everything was ok, the soap is fine, quite hard after 24h, harder then other batches using the same oil formula (is this because of salt?), no any unpleasent smell (lard or pickles).

Pickles brine means water+salt before fermentation, but I use this after 3 weeks of fermentation, so what else then water and salt I put in my soap using fermented brine?

 

[snappyllama]

Hi,

If I am reading the fermentation portion of your post correctly, did you actually use the pickling solution that also has vinegar in it? If so, the vinegar would have neutralized some/a lot of your lye. You may have ended up with an incredibly high SF.

If the only thing you used was a brine solution that contained water and salt (no other pickling ingredients like vinegar), you made a soleseife soap! Salt hardens bars so that would be expected. You might find that your bar doesn't bubble quite as much.... Folks normally up the coconut for more bubbles when using a lot of salt and then up the SF to counteract the drying effects of high coconut.

 

[sososo]

The brine solution was made only of water and salt, no vinegar, but there is some fermentation even with this no vinegar formula, so the brine is not only water+salt, it is acidic.

 

[DeeAnna]

"...use this after 3 weeks of fermentation, so what else then water and salt I put in my soap using fermented brine? ..."

Acid is created by the fermentation process, even if there is no extra vinegar added. See SnappyLlama's post.

 

[sososo]

I know that there are some acid in that brine (my tongue told me), but I don't know:
- what acid
- the ratio acid:water
-the SAP of this acid
I hope that this acid didn't eat too much lye.

 

[DeeAnna]

Acid has no saponification value.
You would need to test the brine to know how much acid there is.
The acid is probably lactic.

 

[sososo]

Acid has no saponification value.
.

I mean how much lye is needed to neutralize 1g o this acid.
Anyway, is almost imposible for me to know how much lactic acid is in that brine. So, hope that everything will be ok with this soap.

 

[DeeAnna]

Lactic acid and Sodium hydroxide (NaOH) make Sodium lactate in soap
10 g lactic acid neutralizes 4.44 g NaOH

 

[boyago]

Lactic acid and Sodium hydroxide (NaOH) make Sodium lactate in soap
10 g lactic acid neutralizes 4.44 g NaOH

Hey DeeAnna (or anyone), how do you calculate the values to get to know how much NaOH is used in acid reactions? This has come up in the past and you seem to be johny on the spot.

 

[sososo]

Lactic acid and Sodium hydroxide (NaOH) make Sodium lactate in soap
10 g lactic acid neutralizes 4.44 g NaOH

So, the soap will be a hard one not only because of salt in brine but also because of sodium lactate.

 

[DeeAnna]

Good point about the SL -- yes, I agree with you!

 

[DeeAnna]

Hey, Boyago -- Part of the answer is that I keep a file of frequently asked chemistry and math questions that I've written answers to. A cheat sheet of sorts. This question about neutralizing acetic/citric/lactic acid has only come up .... oh maybe twenty bazillion times give or take a couple of thousand.

Another is that I have a chem and math background and like this kind of arcane geeky stuff. Here's your daily dose of algebra and chemistry:

Lactic acid + Sodium hydroxide => dissociated ionic species of the acid and base => Sodium lactate + water
C2H4OHCOOH + NaOH => C2H4OHCOO- + H+ + Na+ + OH- => C2H4OHCOONa + H2O

This chemical formula shows 1 molecule of lactic acid is needed to react with 1 molecule of sodium hydroxide.

Side note: This is a concept called the stoichiometric ratio, which is the number of moles of one substance needed to react exactly with the number of moles of another. So the stoichiometric ratio of this reaction is 1:1. The stoichiometric ratio of Sodium hydroxide with any soaping fat is 3:1 -- three molecules of NaOH are needed to react with 1 molecule of any soaping fat.

Side note: Another word to use in place of "molecule" is "mole" which is a more convenient measurement for us humans. A mole (shorthand: "mol") is based on Avogadro's constant, a standard measurement of 6.24 x 10^23 molecules. (Yes, I really do remember this off the top of my head.) Avogadro's number happens to be the precise count of atoms in 12 grams of Carbon-12, the isotope of carbon that weighs exactly 12 molecular units. (No I don't remember that, but Wikipedia is my friend.)

Molecular weight of Lactic acid: 90.08 grams / 1 mol (Source: Wikipedia or an old fashioned periodic table of the elements)
Molecular weight of Sodium hydroxide: 39.997 grams / 1 mol (ditto)

The stoichometric ratio is 1/1, but we don't normally measure in units of moles. We do use weight units, so I want to find a weight ratio that's means the same as the stoich ratio for this reaction.

It's nicer to write a ratio problem out properly by hand, but this is the only way I can show a ratio using this text editor:
(39.997 g NaOH / 1 mol) * (1 mol / 90.08 g lactic acid) = 0.4440 g NaOH / 1 g Lactic acid

Multiply top and bottom by 10 and you convert this ratio into something with easy-to-say numbers:
4.44 g NaOH / 10 g Lactic acid