onoI'm nearing the end of Act 2, and I just figured out that I can unlock alchemy recipes by right-clicking base ingredients to make their extracts.
Press i, open alchemy tab (direct hotkey might be h or something) At the bottom of the window is a button to make all available extracts at once
I saw that button, but that’s not what I wanted to do, so I never used it.
I don’t think there’s any reason not to make all the extracts. AFAIK the unextracted ingredients aren’t usable for anything
There are about 5 ingredients like Corpse Roses where the extract can only be used for a secondary ingredient while the unextracted ingredient is used to create the Potion/Elixir/Coating.
Pretty sure this is outright incorrect. From the wiki:
Each Ingredient converts into only one type of Extract, so there is no danger in using the “Extract All Ingredients” button.
In the underworld a quest needs a raw material.
It’s possible they left 4 laying around so you’d have at least 1 left, but I didn’t have 4 at the time and restored a save to undo it.