Brining out bacon soap

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Mar 30, 2013
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I take bacon grease from the kitchen where I work and use the crock pot hot process method to turn it into soap. I work at a fat discount to ensure complete saponification. I will generally start a batch in the morning, let it boil for a while, turn off the heat, and then bring it back to a boil in the evening. Once the soap is at about the vaseline stage, I add a volume of 8% brine equal to the original lye solution. I'll let this cook for a while, so that as the water boils out, the salt continues to pull moisture from the soap until the soap is floating as thick curds on top of the liquid. At this point, I can ladle out the soup into a normal kitchen strainer, separating the glycerin and other liquids from the soap curds. The soap goes into molds, and I just set the liquids aside until I decide to reclaim the glycerin.

Yesterday, I noticed something interesting. The previous evening had been cool, and the liquid in the container had separated into two layers: a darker, liquid layer on the bottom, and a thicker, lighter-colored liquid on top. A spoon dipped in this thicker liquid and then dunked into a cup of ice water left what appeared to be a greasy slick. Rubbing it between the fingers felt oily. I licked my fingers and zapped the ^&%$ out of myself, so the idea of it being unsaponified fats didn't pass muster. I set the container in the fridge overnight, and the upper layer solidified like grease.

Any idea what this thicker substance is? I doubt it's the glycerin, which should be held in solution with the water in the brine.
I have never heard of this method of making soap. The hot process I have used isn't anything like this. Learning about new methods (new to me) is very interesting, but sorry I can't help answer your question. I will ask why to go to all this and separate out the glycerin? Does it remove the bacon scent of the oil? Does your soap have any bacon scent, just curious.
I have never heard of the way you are making soap. However, I will say, if you zapped yourself doing a zap test, then it's probably unsaponified fats or leftover lye. That is what causes the zap, right, too much lye? Also, oil floats on water, so I'm going for no complete mixture of any kind. This is all speculation, since I've never seen what you're doing, but it's applicable in other scenarios where water and oil literally don't mix.
I don't do it *to* separate out the glycerin, I just keep the liquid on hand in case I want to separate it out later. Waste not want not, after all! I brine the soap because I'm too lazy to thoroughly clean the bacon grease first, and this method pulls out all the impurities. The bars are pure white, odorless, and the fact that it's animal fat makes the bars lather up thick and creamy without the glycerin. The first batch I made, I was pretty impatient and didn't wait for the brining to finish completely, so they're a little smoky when lathering, but they rinse clean with no residual smell.
When making boiled soap different fatty acids salt out at different salinity percents. Times and temps are more important with this method than with cold or hot process, maybe you were off a bit? Also I'm assuming you know that as this is done to help get rid of the extra lye, along with other things, it makes since that this liquid would be zappy.
I think there is another member here that was working with this process maybe he will check in.
Oops, you posted while I was typing, looks like you are not doing what I thought you were.
sistrum, thanks so much for the information! I got my method from a book from the 1800s, and there wasn't much detail about salinities or anything like that. They mostly talked about "boiling on strength" and other archaic terms. I did recognize that the pot liquor would be caustic due to being brined out, but I figured any additional fatty acids would be saponified in the presence of that lye.
Go to the free iBook place and look for a different book, they have quite a few, read some early 1900's they changed a lot over the next few years as chemistry was just starting to get going in the soaping industry. Plus they just have so much good info on all kinds of stuff.
for sure. I ended up refrigerating the liquid, and the top layer solidified like fat. I scooped it out and used it in my latest batch of soap, and it seems to have been soaked up one way or another. The mystery may not have been conclusively solved, but it has disappeared!

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