What is Salting Out Soap?
Salting out soap can be considered a type of rebatching, in that it’s a great way to use up soap scraps to make something new. While it’s more time consuming, it does have its perks. Namely, removing unwanted additives – including color and scent. Granted, some colors may remain, but this can be a huge benefit when dealing with many unwanted colors. FYI: In the tutorial videos I’ll be salting out some blue soaps. Indigo is a bear to salt out as it truly stains the soap blue. Don’t expect to see super white salted out soap in the tutorial, but don’t be surprised when your salted soap is white!
Salting out is a purification process that works by precipitating certain molecules out of a solution based on their lower solubility level. When you add salt to a solution (like soap dissolved in water) some of the water molecules are attracted to the salt, leaving fewer of them available to interact with proteins in the solution. Essentially, when you dissolve soap in water, and then add salt, the water loving (hydrophilic) components of the original soap bar stay dissolved. The water fearing (hydrophobic) molecules float to the top!
When salting out soap you will also remove the naturally occurring glycerin and the superfat (they don’t float to the top with the raw soap mass). Sometimes that’s exactly what you want (i.e. making a great powdered laundry soap). While other times you’ll want to add some of that goodness back in (for body soap).
In this tutorial I’ll walk you through the basic process of salting out soap, how to make new soaps from our salted out soap mass, and most importantly… the math behind it all. I promise that there’s only a smidge of basic math, and I’ve included worksheets to make sure it doesn’t give you a headache.
Since I brought up the math, there’s one more thing you should know: salting out soap is a balancing act of math and experience. The percentages and equations I provide are general guides, not hard and fast numbers. Once you salt out a few batches, you’ll have a better “feel” for the process and an understanding of what works best for your recipes.
Let’s get to it, shall we?
