I am in regular conversations with wet shavers who use cartridge razors, safety razors and straight razors in their daily shave routines. In my discussions, I find it interesting to note how many cartridge razor shavers keep their razors in the shower and simply use the water of the shower and a little hand soap to shave while they are in the shower.
Unfortunately, for single blade shavers–like those using safety razors or straight razors in their morning routine–the saponification effects of hand soap and a little how shower water, is usually not enough protection against the greater aggression of a single blade shave. In most cases, hand soap excludes the higher fat content required to create the thick lather most single blade shavers require. In short, those that use shaving soap require a greater emphasis on the functional benefits of the soap than those that simply use hand soap to shave.
The best artisan soap makers understand this fact and tailor their soaps different depending on the demand of their particular customers. As a direct example, artisan soap makers will add either plan or animal based fatty carbon chains to their shave soap recipes, much more so than the recipes they use to create hand soap.
To the non-discerning cartridge razor connoisseur who simply shaves in the shower, the thick, rich lather of a quality shave soap is of little consequence, but the most discerning wet shavers (typically those who use straight razors and safety razors) demand more.
They want a functional lather that builds easily with just a little added water. They desire function, but scent is also important. Artisan shave soap makers are gratefully become more adept in providing what the wet shaving market demands: shaving soap that both provides the creamy function and both traditional and modern scents of the most masculine men.
Hand soap, and even the best smelling artisan hand soap, does not always cut it.