Water discounts with beer/milk

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Mschwartz

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I made a Guinness beer soap this last weekend and it’s got soda ash. I combined the oils and lye/beer at 85F. The beer was frozen. This was the recipe. Water discounts are supposed to help this? Can you discount 100% beer/milk recipes? Thanks.
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Hello from Boise to wherever you may be in the great state of Idaho! Yes, a water discount can help with ash. Since neither beer nor milk is 100% water, I'd probably stop somewhere around 37% lye solution just to be sure there is enough water to dissolve all the NaOH.

Applying some post-mixing heat (whether in the oven, on heating pads, or insulating) can also help prevent or reduce ash, but that can be tricky with milk soaps and beer soaps, due to the extra sugars. Have you tried keeping the soap tightly covered and in the mold for at least 24 hours or longer? The further along it gets into the saponification process, the less unreacted lye is available to create soda ash.
 
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I put the molds in the freezer due to being scared of the sugars.
That does slow down saponification, so you will probably need to leave it covered longer to prevent ash. If you feel like it is getting too hard and needs to be cut, you can always cut it and then wrap the bars up for a few more days before exposing them to the air for curing.
 

Mschwartz

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So ash only happens during the initial setting up not during curing? I’m on the south east part of the state.
 

Mschwartz

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So I guess I’m still a little confused as to water discounting with beer/milk if it’s 100% of the water portion. Can you do it? I know low soaping temps and freezing after pouring keeps the sugars from scalding. So just cover with plastic and all should be well?
 
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So I guess I’m still a little confused as to water discounting with beer/milk if it’s 100% of the water portion. Can you do it? I know low soaping temps and freezing after pouring keeps the sugars from scalding. So just cover with plastic and all should be well?
Just whatever the water amount is, replace it with beer. I have used this method having frozen my beer into ice cubes.
I do not worry about keeping beer soap cool. All my soaps gel, and that in turn helps prevent ash.
I have never used animal milk as my water ( only oat milk) so I can’t speak to that. When I used coconut milk I used the split method and added it to the oils.
Surely the lye when mixed with milk would start saponifying right there inthe lye solution? That is one thing I just can’t get my head around and why I use the split method.
 
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So I guess I’m still a little confused as to water discounting with beer/milk if it’s 100% of the water portion. Can you do it? I know low soaping temps and freezing after pouring keeps the sugars from scalding. So just cover with plastic and all should be well?
Rather than talking about a water discount (which means different things to different people), it is better to think about it in terms of lye concentration. That is the setting you actually used in the recipe listed above, so that's great.

As @KiwiMoose noted, you really don't have to worry about using beer or milk to replace 100% of your water... UNLESS you were going to make a 50% lye solution. Because neither the beer nor the milk are 100% water, you would not have enough liquid to dissolve the NaOH. That in turn would leave undissolved lye crystals in your soap - no bueno. That's an extreme example, however, because I don't know anyone who actually soaps with a 50% lye solution!

As long as you are using a more typical lye concentration (anything 40% or below is my personal comfort level), then you don't need to worry when using beer or milk as a complete water replacer to dissolve the NaOH. However, that is not the case if you were using, say, a straight carrot puree with no water added. Pure carrot puree is significantly less than 100% water. For a thicker water replacement such as that puree, I'd probably want to use a lye concentration more like 30-33% to ensure that the puree has enough water in it to dissolve all of the lye.

Hope that makes sense!
 
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