For soap in general, you take a small slice off after 2 weeks and wash your inner arm with it. If you don't get a fun burny tingle, roughly the equivalent of sports cream, it's cured. If you do, wait another week and try again. Wash, rinse, repeat.. hah, literally.. until no more burny fun. Hot process cures a lot faster than cold process.

With mine.. I'm going to have to just wait the full three weeks. After that, I'll still have the fun of clove oil and ground cinnamon tinglies, but those don't eat holes in my skin like lye would.