We (Tricia and Jamie) invented the phrase "Exfoliant By Volume (%EBV)"TM to describe the perceived abrasiveness (scratchiness or smoothiness) of beer soaps. Similar to the way the increased Alcohol By Volume (%ABV) value describes the strength of a beer, %EBV indicates the abrasive strength of a soap: the higher the %EBV value the more exfoliant is present.
Light Exfoliant (0-7.9%EBV) is derived from either no exfoliant, some spent hops or some spent grains. These pellet hops or grains have been used in the brewing process and provide a subtle scratch that is great for clearing away dead skin cells. We tried using hole leaf hops but they ended up being too difficult to wash off and looked kinda gross in the tub. So, if you ever see leaf hops on a BeerCanSoap bar it is a harmless decoration.
Heavy Exfoliant (8-16%EBV) is derived from combining spent grains with spent hops, or in the case of our chocolate espresso soap - coffee! Again, we use hops and grains that have been exhausted in the brewing process. First the grains are milled and mashed to release the vital sugars necessary for making homebrewed beer, then a thin layer of grains gets spread onto cookie sheets and allowed to dry naturally in the sun. Once completely dried the grains become an excellent natural exfoliant. Just like a strong brew, apply higher %EBV soaps with adult supervision.