I'm hoping to forgo buying sodium lactate and instead use kefir which I have a steady supply of. The problem is that I don't have any idea how much lactic acid it contains and how much extra lye I might need to add to make up for it. Should I just calculate a recipe with a lower superfat than usual and hope that the reaction takes a reasonable course? Is this a bad idea?
Using the kefir as a source of lactic acid
- Thread starter milky
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BrewerGeorge
Well-Known Member
I tried something similar with yogurt whey which is about 7% lactic acid. I know kefir is typically more tart than yogurt, but not how much lactic acid it contains - maybe 2% at most? Also, depending on your process and culture, you may have ethanol and/or acetic acid from ethanol.
Cool! How did your yogurt whey soap turn out? I'm going to start making yogurt more often once our new yogurt maker arrives and can try that instead of kefir. What would ethanol or acetic acid do to the soap?
In cp, any alcohol can cause instant "soap on a stick" - the soap goes solid far too quickly and you have to try to smoosh it in to the moulds.
As for the acid, in cp it will react with some of the lye to form sodium acetate. It's good for making hard bars in general, but as it will use some lye you should know how much to adjust by in case your lye discount is then too high
As for the acid, in cp it will react with some of the lye to form sodium acetate. It's good for making hard bars in general, but as it will use some lye you should know how much to adjust by in case your lye discount is then too high
BrewerGeorge
Well-Known Member
Just fine. I only did it once, and I didn't do a control recipe to compare it to, but it worked. Prepared sodium lactate is so much easier that I never did it again. Note that I used the whey left over from straining yogurt into Greek yogurt, not whole yogurt.
Kefir is going to be pretty hard to use reliably, IMO. It's quite a lot more variable depending on the mix of bacteria and yeasts in the cultures used to make it. Are you making your own or buying, BTW? If there is a lot of yeast, you could get a percent of two of alcohol. If there are acetobacter and oxygen exposure, that alcohol will turn to vinegar. Meanwhile the lactobacilli are competing for those same sugars to make their lactic acid. So every cup of kefir is a bit of a crap shoot as to what exactly is in it.
Plus, it's thick enough that it's going to be hard to use enough to get the lactic effect. (I replaced half my water with whey.)
Yeah, I can definitely see how it would be a crap shoot. I make my own. A bit too often I put off feeding it and it gets more yeasty then. End up making a lot of "buttermilk" bread stuffs, which is great except for the low carbers around here. More for me! lol.
Not soap related, but have you gotten into cheesemaking at all?
BrewerGeorge
Well-Known Member
Lots of the brewing crowd move naturally into cheese, and I looked at it pretty hard. After a lot of research and asking a lot of questions of experienced cheese makers I decided against it. The consensus from all those people is that it's not worth it unless you have access to a lot of high quality milk. Raw milk especially. They say grocery store, pasteurized homogenized milk makes cheese that tastes like Kraft or Sargentto with a lot more work.
milky said:
You could do an acid-base titration to determine the amount of NaOH (or KOH) needed to neutralize a given amount of kefir.
Essentially, you’ll want to:
1. Make a NaOH solution of a known concentration. Weigh and record the combined weight of your container, the NaOH solution, and a pipette (that will be used later).
2. Measure out a known amount of kefir into a beaker, add enough distilled water to thin it out, and then stir in 3 drops of phenolphthalein indicator solution.
3. Slowly add (drop-by-drop) the NaOH solution until the kefir turns a light pink color; be sure to stir the kefir while adding the NaOH solution. You might get a localized color change, but if stirring removes the color, keep adding the NaOH solution. Your end point is indicated when the entire kefir solution is a light pink color. At this point, don’t add any more of NaOH solution. Dispose of the neutralized kefir—don’t drink it and don’t soap with it!
4. Weigh the beaker of remaining NaOH solution AND the pipette; subtract that from the combine weight in step 1. The difference is the amount of solution required to neutralize that batch of kefir.
So as an example, if you make a 10% NaOH concentration, and it took 8 g of solution to neutralize 10 g of kefir, you’re math would look like this:
8 g NaOH solution x 0.10 = 0.8 g NaOH
In this example, 10 g of kefir would need 0.8 g dry NaOH (or 8% by weight). Please note that is an example—I have no idea how much NaOH is needed to neutralize your kefir, or any other’s for that matter. You’ll need to do this each time you make soap.
As far as alcohol content. . . . I probably wouldn’t worry too much about it. Adding NaOH to the kefir is going to release a lot of heat and will probably drive some of the alcohol out. I don’t know much about kefir, but milk isn’t that high in sugar (and on average, sugar only yields half its weight in alcohol).
