Congrats for elminating the spellcaster requirement for making gunpowder. This was a stupidity introduced by 3.5.
I would, suggest however, going a bit further.
Simplest is to ditch the spellcaster requirement for alchemy across the board.
Alternatively, there is a cutting-edge alchemy not based on magic that is in fact proto-chemistry. This can be found in Lamordia and similarly modern domains. And there is a traditional alchemy based on knowledge of magic. This can be found in Barovia and similarly less advanced, but not primative, domains. The first can make gunpowder and a range of non-magical substances, but could not produce an all purpose antitoxin, let alone necromantic substances like brittlebone, ghost oil, or positoxins. The second can make all purpose antitoxin, necromantic substances like brittlebone, ghost oil, or positoxin, as well as a range of mundane substances, perhaps, but not necessarily, including gunpowder.
Some detail on the matter can be found here:
http://fraternityofshadows.com/wiki/Category:Alchemy