Do you need to learn recipes first to use Craft (Alchemy)?

Question

A character in my group, now at Level 2, put Ranks in Craft (Alchemy). He has not actually used it yet, but plans to do so.

My question is:

Which alchemical items is he at least theoretically able to craft? This is not about crafting time or DC!

There are hundreds of items across the rulebooks listed as "Alchemical Items" — alchemical powders, poisons, drugs, arrows, etc.

Are there any RAW/RAI specifying which of these items he knows how to craft? How many? Up to a specific DC/price?

If he does not know all alchemical recipes, how does he acquire new ones?

Answer 1

By default, a craftsman can use the skill Craft to create any and all alchemical items if he meets the requirements for crafting alchemical items. (Usually, all a craftsman needs to be able to craft alchemical items is raw materials, but appropriate tools help a lot. Pathfinder removed the restriction of its its forebear—Dungeons & Dragons 3.5—that to create alchemical items requires being a spellcaster.)

Yes, that means the craftsman can create the hundreds of alchemical items scattered across dozens of books—no special research is needed to learn any fancy secret formulas, for instance.

This isn't in any way unbalanced. While it may seem strange, the limiting factor is time: it can take a craftsman days or even weeks to create even a lone flask of alchemist's fire, for instance.

And, of course, a GM can rule that some alchemical items do possess secret formulas, unknown to the PCs that must be discovered during play. However, such items are usually better suited as actual magic item as the creating magic items is usually gated behind much stricter creation prerequisites.

Answer 2

We label things names for convenience to quickly identify specific effects, but that doesn't mean something that creates the same effect is created the same way. There is nothing saying you have to create an alchemist fire a very certain way. There is nothing saying an alchemist fire only works buy spewing out a small amount of liquid fire. As long as the end result is the same, it doesn't matter how its created or what materials are used (except for cost purposes).

Dont think of alchemical items as specific recipes. Think of them as desired effects. A skilled alchemist knows how ingredients react with each other and under different circumstances. If your desired effect is a bomb, chances are he can create one with hundreds of different combinations of ingredients.