As per the magic item creation rules, it seems it is impossible to craft more than one magic item a day. This should include potions.
Regardless of the time needed for construction, a caster can create no more than one magic item per day.
This seems incompatible with the Mutagenic Mixology (Ex) ability of the Concocter alchemist.
It says that when you brew a potion, you can infuse it with mutagenic powers. At lev 4, you can make this twice a day.A concocter can make one such concoction per day at 2nd level and a second per day at 4th level. A concoction becomes inert 24 hours after it is created.
For this ability to work as written, you need to be able to brew at least two potions a day. At first this seems to be incompatible with the magic item creation rules, but I can see a few possible things going on.
1. This is a specific exception to the rule. When using this ability you can brew more than one potion a day, but only when they are being infused with a mutagen.
2. The original rule states that a CASTER can create no more than one magic item per day. Here they refer specifically to casters. But in the FAQ, paizo says that alchemists are basically not casters.
Alchemist: Is an alchemist a spellcaster for the purpose of crafting magic items other than potions?
As written, no, alchemists are not spellcasters, and therefore can't select feats such as Craft Wondrous Item.
The design team is aware that this creates some thematic problems with the idea of an alchemist creating golems and so on, and plan to examine this in the future.
If we go pure RAW based on that, would it not imply that alchemists are exempt from the 1 per day limit for crafting potions? They cannot take other crafting feats anyway as they lack the prerequisite of having caster levels.
3.Somehow we are all wrong about the 1 per day limit applying to potions, scrolls and consumable magic items in general, this rule was intended for other things. I say that is very unlikely as the rule seem quite clear. But really this rule is weird. Why would a lev 20 cleric be unable to brew more than 1 potion of cure light wound a day? This is silly and if I was running a game I would house rule that you can, as long as you stay withing the 1000GP per day limit. Unlikely to see any kind of abuse with that, potions are expensive and situational. Wand crafting is already a lot more powerful than potion crafting, even with the 1 per day limitation.
Please help me make some sense out of that.
Specific trumps general : this is an exception to the one per day rule.
Not the only one either, another example being witches, who can get a major hex that allows them to brew more than one potion a day (proving the limit does apply otherwise, btw). Not to even touch on the Druidic Herbalism weirdness.
I'm never sure how the Alchemist's very own Dilution works in that regard, but it could be another one ? Or not?
If the limitation did not apply to non-casters, Master Craftsman would be better than it is. I'd assume it's more likely the wording showing its age : there simply was no non-caster option for magic item creation back then.
Snip.
Thank you for this insightful answer.
I'm wondering why the OP didn't check Brew Potion feat. As it clearly states "Brewing a potion takes 2 hours if its base price is 250 gp or less, otherwise brewing a potion takes 1 day for each 1,000 gp in its base price."
So no Concocters don't have any special ability to make potions faster. If you want to make 2 mutagen laced potions in a day they need to be 250gp or less in value so you can make them in 2 hours each. Since you are limited to 250gp or less in value, that means a 1st or zero level potion as the cheapest 2nd level potion is 300gp. A 250gp potion could be a CL 5 1st level spell, or a CL 10 zero level spell.
Funny that you assume I did not read the Brew potion feat or something. Nowhere does the feat say that you can make more than 1 cheap potion per day. Only that cheap potions takes you less than a full day of work. You are still bound by the magic items creation rules which limit potions to 1 per day whatever time it takes. It even says explicitly that the time requirement for crafting does not affect the 1 item per day limit. I actually even quoted that very part in my original post. My very first quote of the post.
This rule would apply unless a specific exception comes along, as Nyerkh pointed out.