Beer soap is the product of two ancient crafts – beer (5000BC) and soap (2800BC). Here at Ka Lab, we do not brew beer, but use beer to make artisan soaps.
Literally, any kind of fat or oil can be converted to crude soap by combining it with a base solution – the process is called saponification. There are two types of saponification – cold process, and hot process, in which heat energy is required. We use both methods.
According to American Food and Drug Authority, only soaps that come out of saponification process are called ‘soap’, ‘crude soap’ or ‘natural soap’. Cleaning products made from other synthetic process are ‘detergent’, ‘beauty bars’, or even ‘soap without soap’. Soaps are naturally alkaline.
During the saponification process, all lye is used up, natural vegetal glycerin is formed, and some fatty acids (oils/fats) are left (superfat) and stay inside the soap. Therefore natural soaps is a cleaner, a moisturer, and a bio-product and best be used within, in general 3 years.
As some minute quantity of oils/fats are left in the soap, if the soap is not stored properly – in cool dry conditions and preferably ventilated – the residual oil may become rancid and produce a phenomenon called DOS – dreaded orange spots on the soap.
So if you forgot a natural soap at the bottom of your bathroom drawer and take it out after, say a year or more, there is a chance the soap smells rancid oil and bear some DOS.
DOS, has no effect on the cleaning power of the soap, nor undesirable effects on our skin, just that it makes the soap smells bad. You can just cut away the orange spots and the soap can still be used. 
Article by KA LAB
