Goat milk and lye issue

[Buckscent]

So I have always mixed oils and lye and soaped right then at 110-120. We’ll tonight I got my frozen goats milk and mixed my lye 13.68 oz to 5.08 oz. my wife came into my shop and we had to leave right then for an issue that came up. We got back about 3 hrs later and when I went to the shop my GM and lye mixture was like the consistency of a, well idk, like a semi hard body butter but yet I could still move it around with my spoon. Not liquid by any means. I mixed in my oils and soaped. It acted fine, trace was right where I wanted it. Just never in all these years let lye sit out that long.

 

[Mistrael]

Oooh, do you think the lye started working on the fat in the GM when you weren't looking?

 

[Michele50]

Since milk products contain fat, what @Mistrael said is what I believe happened. It just didn't have enough fats for the lye to turn it into 'soap'.......not for lack of trying on its part. Glad all worked out well and as expected for ya.

 

[Buckscent]

Yea I’m sure that’s what it was. Just weird I have never done or seen that before. I never had to worry about that with water. Never thought about the fat in the milk

 

[Michele50]

Yea I’m sure that’s what it was. Just weird I have never done or seen that before. I never had to worry about that with water. Never thought about the fat in the milk

What you described I've had happen when using frozen cubed goat's milk because it took a while for the lye to dissolve and to melt the milk cubes. Since it took a while, the lye was working on the fats (trying to turn them into soap) as it dissolved and melted the frozen milk cubes. I've seen some people make cubes and then also use some not frozen milk. I'm sure the reasoning behind this is to keep the milk cold enough so it doesn't scorch and turn brownish but not have it take forever to get the lye solution ready for soaping. I haven't tried this (cubes AND liquid) to see how much time it cuts; it also would allow the solution to be warmer. When I've used cubes the end result is a solution colder than I desire. Same when I use frozen beer; it's a 100% water sub so it too is colder than I want. When all is melted I'd heat water in a pot and set my container into it to heat the solution some.

 

[shunt2011]

Yes, what you experience is that the lye saponified the milk fat. I no longer add my lye directly to milk. I always mix it with water then add my milks enhanced with powdered to make it full strength to my oils before my lye mixture. Takes met less time an much easier.

 

[DeeAnna]

I'm betting the fat in the milk reacted with the NaOH, but another possible reason why it was thick is that it might have been extra cool.

Your lye concentration was 27% if the liquid had been 100% water. Your solution was probably a tiny bit more concentrated since you used milk instead. A 28% to 30% NaOH solution will start to freeze at 32F / 0C give or take a bit. Slightly above its freezing point, the lye solution will be thick and syrupy. Obviously by the time it warms up to normal room temps, the solution is more like water.

Not sure how cold your lye solution was when you returned, but if it was pretty chilly, the temperature could also have contributed to the solution being thick.

Think of putting honey in the fridge -- it gets thicker and a lot harder to pour. Same thing happens with concentrated NaOH solutions like we use for soap making.

***

Here's a related tip, although a little off the OPs main topic --

For those who make their masterbatch at 50% NaOH concentration, you should be aware this even more concentrated solution will freeze at a LOT higher temperature -- about 55F / 13C.

If you let a 50% NaOH solution get that cold, a hard layer of solid NaOH will form in the bottom of your container. The solidified NaOH behaves more like rock crystal candy than water ice -- it takes time and effort to get this layer re-dissolved, even after the solution warms back to normal room temp.

The solution will be very thick, like cold honey, as the temp drops below about 65F / 18C. You won't have solid NaOH to deal with, but it is hard to pour and measure accurately.

I recommend keeping 50% masterbatch lye at 65F or warmer to avoid all this trouble.

 

[IrishLass]

I make my goat milk soaps the same way as Shunt (i.e., the 'split method'). It shaves off so much time and hassle, and there's no discoloration to tan in spite of the goat milk not being in a frozen state..... nor even in a merely cool state for that matter. Ideally, I like my goat milk to be at room temp by the time I soap.

I work from a 50% lye master-batch, so when I want to make a goat milk soap, I just use fresh goat milk in place of the extra water amount that I would normally need in order to bring my soaping lye concentration to a 33% concentration (my favorite soaping lye concentration), and then I fortify that amount of fresh goat milk with enough powdered goat milk to bring it to whatever would equal out to be a full strength amount of goat milk for the total required liquid amount for my batch.

When I go to soap, I add the goat milk slurry to my melted fats/oils either before or after I add the lye solution. Either way works fine. My resulting soap always comes out off-white/ivory.


IrishLass