Revolution d100 has the idea of Stunts that belong to Traits that belong to Skills, so a Skill might be Knowledge and have an Alchemy Trait, but Alchemy might have Healing Potion, Poison Antidote and Acid as Stunts, acting as recipes for Alchemy. RQG could do something similar, but it isn;t obvious how it would work from a rules poijt of view. maybe recipes are treated as spells, so you have room for a certain number of recipes.
I would guess that Alchemists would write their recipes down using some kind of Alchemy language that is encoded so that non-Alcehcmists can't use it. Non-literate cultures would learn the methods, or have them encoded in songs, poems, stories or dances.