When it comes to additives in soap, I tend to be a bit skeptical as there are very few additives I feel make a huge difference to the final bars. There are three I use religiously – silk for lather texture, sugar for lather volume, and sodium lactate for bar hardness. These additives go into every batch of soap I make.
Recently, I’ve discovered another additive that is just as impressive – butter powder – unsalted, spray-dried butter powder to be exact. It makes the creamiest, most luxurious bar I’ve ever tried.
Butter powder contains a whopping 73% fat, three times the amount of sheep’s or cow’s milk powder. Because the milk is in powder form and not liquid, the fat does not need to be taken into account for saponification purposes, meaning the bar is super-fatted (or as I like to say ‘ultra-fatted’) without compromising the recipe or the final bars of soap.
The method I use for adding milk powders to soaps is slightly different than most. I never reconstitute the milk, but simply make a thin paste (or slurry) with the milk powder and a few teaspoons of the oils from my recipe. When making CP, I add this mixture at trace, just before adding the fragrance. When making HP, it goes in a few minutes after the soap has been removed from the heat and allowed to cool slightly. Doing it this way gives the soap all of the benefits of milk without the pitfalls of off-smells and the possibility of rancidity.
So will butter powder join silk, sugar, and sodium lactate as a must-have additive? Probably not. In this case, I’ll continue to give my customers a choice and perhaps offer one or two soaps with butter powder. I will, however, be including it in every batch I make for myself. I won’t be going without this little luxury in the future.