Sodium lactate from yogurt?

[Sonya-m]

Just reading the apple cider thread and DeeAnna's reply about yogurt in soap producing sodium lactate interests me.

A bit of research tells me lactic acid is mostly present in sour products such as yogurt.

My question is, would adding yogurt (or buttermilk and lemon juice) produce enough SL to have the effects that adding straight SL does? And would there be any other benefits from using yogurt over SL?

I ask because I've been wanting to try SL but just haven't gotten round to ordering any yet but obviously yogurt is readily available.

 

[snappyllama]

I'm bumping this with some questions about yogurt too... I hope you don't mind, Sonya. Feel free to shoo me away and tell me to get my own thread

Does yogurt boost bubbles/ in a similar way as other milks?
Does it give folks that butyric acid after-smell that some folks (me) can detect in cow milk/heavy cream soaps?
Do folks have a yogurt preference... greek, plain regular, something else?
Do you adjust down regular amounts of SL if that's normally in your recipe when using yogurt?

 

[Sonya-m]

No ask away!! All stuff I'd like to know too.

 

[DeeAnna]

Cultured buttermilk and yogurt have lactic acid. Lemon juice contains citric acid. I couldn't find any info on the approximate amount of lactic acid in yogurt or buttermilk -- maybe y'all can do some researching on this? Sodium lactate solution as purchased is about 60% SL if my memory is correct. It is often used in soap at 1% to 3% ppo.

Yogurt or buttermilk would have to contain very roughly 5% to 10% lactic acid to create the same amount of SL in soap as adding 2% of commercial SL solution. That seems like a lot of lactic acid for a food product, but I really don't know the facts.

 

[galaxyMLP]

According to this article:
http://www.ijens.org/vol_12_i_01/124901-8585-ijbas-ijens.pdf


Even with special starch oligosaccharides (food) for the bacteria, it seems the lactic acid content is 0.8-1%.

 

[kchaystack]

I saw a video of someone adding yogurt powder to their soaps. I wonder that has more lactic in it than actual yogurt.

 

[OliveOil2]

I have found Kiefer had more effect than yogurt, but this is just an observation, and I haven't done any experiments to compare. It did make a very nice soap with lots of bubbles

 

[DeeAnna]

Thanks, Galaxy! So if I assume typical yogurt contains 0.5% to 1% lactic acid, allowing for the fact that most yogurt isn't "supercharged" with bug food, then using yogurt as a substitute for all water in a "full water" soap would add roughly 2 to 4 grams of lactic acid per 1000 grams of oils. If the yogurt is used as half the water, then it would add 1-2 grams.

KC -- If you add enough yogurt or buttermilk powder to water as if to re-hydrate the dairy to its original consistency, no, it won't contain more lactic acid than the non-dehydrated dairy from which the powder comes. It's just the dairy without the water, after all! If you add more powder than is needed to reconstitute the dairy, then obviously yes it would add more acid.

 

[kchaystack]

Yeah I have no plans to try it. I will just keep buying SL from Nurture.

 

[galaxyMLP]

So, thats about 0.4% theoretical maximum SL for using yogurt in place of water? Plus, if you get some yogurt powder, you may be able to double that amount at lets say 0.8%. Thats not too bad! Maybe thats why people love adding yogurt powder to their HP soaps online. If it was me, I'd adjust the super-fat down 1-2% though to accommodate for some of the lye being chewed up.

I'm not saying it will replace the SL we add but, in a pinch, it might help with some fluidity/unmolding if its all you've got.

 

[Sonya-m]

Thank everyone. I guess the answer is to buy some SL.

Ps not sure where I read that adding lemon juice to buttercream had any effect?!? I obviously made that up - not sure why as I know it's citric acid in lemon juice???

 

[DeeAnna]

Sour milk -- 1/2 to 1 tsp vinegar or lemon juice in 1 cup regular milk -- is sometimes used as a sub for buttermilk. Maybe that's where the idea came from?

 

[Sonya-m]

Ah yes maybe that was it - I use buttermilk in the muffins I bake so could be that when I've ran out before