As long as you're dealing with spells of 3rd level or lower, it should act as Brew Potion.
So the same rules apply, except you don't have to pay for the components as long as you have free stuff available. That should be the only difference.
Now, you might notice issues, and wouldn't be the first : it's a weird, unclear ability that's been hotly debated on a regular basis, including fairly recently. A quick search will get you the threads, for more info and speculations.
And at a first reading it doesn't use the spell slot.
There are a couple of ways people have interpreted this.
The two major lines of thought are:
1. Using a spell slot to make a potion isn't a "cost" per se, and therefore isn't included by the term "free". Similarly, the time to create a concoction would still apply (time isn't a "cost"). Therefore, you get to skip the gp cost of 50*SpellLevel*CasterLevel, and nothing else. This is probably the most commonly held belief, although that may be partially due to the average person on here being more conservative when interpreting rules.
2. A "free" concoction has zero cost requirements, so there are no costly component expenses, no time, no spell slots, etc. This is supported by the line later on that specifies that a druid DOES have to expend the slot to make his "extracts". However, some interpret that as just being an example of restating rules, rather than pointing out an exception by omission.
There are other interpretations, including ones that completely break the game (like selling concoctions with a high enough diplomacy check), and ones that make herbalism useless (such as trying to apply the "can only create one magic item per day" rule to potions).
Of the two real options given above, I prefer the latter, because I think that merely gaining the ability to place 3rd-or-lower spells in the form of potions is far less mechanically beneficial than an animal companion. Furthermore, it competes more directly with domains this way; a domain grants an extra slot for each spell level, uses fixed spells (determined by the domain), and grants the domain powers. Herbalism would effectively grant additional 3rd level spell slots, but can be used with a greater variety of spells (anything potion-legal in the druid list) and also gives the ability to convert higher level spells into infusion form (which is primarily useful for giving personal range spells to party members). The direct comparison then would be that herbalism gives slightly less inherent advantage than a domain (because the free spells are capped at 3rd level, no domain power, action economy of having to draw and use a potion vs directly casting), but gives much more flexibility (because you can stockpile potions that would otherwise be situational, hand them out to allies to share action economy, etc). I'm playing a druid with herbalism right now, using the "free includes the spell slots" interpretation, but also unable to sell the concoctions at all (which is really where the option can be broken if not held in check by GM). So far it's been pretty balanced (character started at level 7 and is now level 10).
Additional. Costs a slot. My 2 cents.
Not THAT free.
So then you have to use 2 slots for the ones above 3rd level?
Per Herbalism you can.
Additionally, at 7th level, a druid can create any herbal concoction in 1 minute. She can also create a special concoction of any spell higher than 3rd level that she can cast, but to do so, she must expend a spell slot of the same level. These special concoctions do not cost her anything to create and function like extracts created by an alchemist with the infusion discovery.
And it's that section that talks about expending a spell slot that makes people wonder if making them 3rd or lower don't expend slots.
And I can see that logic as well since it does say it works as extracts.
3rd level or lower concoctions: It is a potion. It takes a slot to create just like a potion would, but after a day it doesn't take anything to maintain.
4th level or higher concoctions. They aren't permanent potions, but work like alchemist extracts, in particular "As long as the extract exists, it continues to occupy one of the alchemist’s daily extract slots."
If it explicitly says that above third level does, then by extrapolation, it does not for first to third. By making a specific rule that states when it does, it automatically does not when those conditions are not met. I forgot about that notation in the Druidic Herbalism thing.This wording from the ability though means it takes a spell slot:
This acts like the Brew Potion feat, but only for spells on the druid spell list.As brew potion takes a spell slot.
You typically cannot make a potion higher than level 3, hence the extra wording.
Ah, yes, but that would be sufficiently covered under "these concoctions function as an infused extract". As infusions take a spell slot, the extra wording would be unnecessary. So the judgement call comes down to "did they decide to restate existing rules for one type of concoction (extracts) but not the other (potions), or did they specifically call out expending a spell slot for extracts to differentiate them from the potions (e.g., making it clear that the benefits of the druid's free concoctions each day does NOT apply to extracts, which already have no gp creation cost but DO have a spell slot cost)?"
In the absence of clear writing, I tried to just estimate the overall benefit of each interpretation, compared to the other druid options, and use that as a guideline.
Actually infusions don't take a spell slot. They take an extracts per day slot.
Extracts/Infusions are not spells.
Actually infusions don't take a spell slot. They take an extracts per day slot.
Extracts/Infusions are not spells.
Curse you, that's probably the best explanation I've heard for including the "must expend a spell slot" text. It assumes the author really knew what they was doing in wording that ability (iffy), but it does provide a perfectly reasonable explanation for why that line was necessary, RAW. I admit, I've rarely had to deal with Alchemists, and generally think of them as BASICALLY casters, but this is one of those times when "spell slot" vs. "extract slot" would actually matter.
I don't personally like it, but I'll accept your interpretation as the RAW. Both "potion" concoctions and "extract" concoctions require a spell slot, but the former lasts indefinitely (and can therefore be stockpiled).
Actually both last indefinitely just one eats up the slot until it's used the other doesn't.
When the alchemist creates an extract, he can infuse it with an extra bit of his own magical power. The extract created now persists even after the alchemist sets it down. As long as the extract exists, it continues to occupy one of the alchemist’s daily extract slots. An infused extract can be imbibed by a non-alchemist to gain its effects.
Actually both last indefinitely just one eats up the slot until it's used the other doesn't.
This is technically true, but functionally there is no difference between keeping an extract around and preparing it everyday.
And the stockpile issue is the big one. A druid could, over time, have 100 Cure Light Wounds concoctions, but they couldn't have 100 cure critical wounds concoctions.
The main thing is that if you lose it you lose the spell slot till it gets used or recovered, you can't just undo the magic the next morning.
Looking over this I have to wonder is there anything like boon companion that would boost your herbalism level if you multiclassed?
Looking over this I have to wonder is there anything like boon companion that would boost your herbalism level if you multiclassed?
I doubt it. I mean, I could have missed something, but I never found one. The most likely way it would happen (I'd imagine) would be something that boosts "Nature Bond" (because no new material will ever mention "herbalism").
However, the Dawnflower Anchorite prestige class (from Paths of the Righteous) has an ability that lets you add those prestige levels to your original class levels for the purpose of determining some class features (wild shape, domain, or animal companion). Given those last two, and considering that any druid with herbalism is in a home game anyway, I don't think it would be an unreasonable request to ask the GM to allow you to take the ability for herbalism.Of course, one thing I forgot to consider, when comparing herbalism to a domain, is that herbalism itself maxes out at 7th level. If you choose to prestige into something that progresses your spellcasting after level 7, you lose literally nothing (from an herbalism standpoint).