[RPG] How do extracts based on Communal spells work


One of my players asked a very interesting question. Their playing an alchemist. Their wanting to know how their communal extracts works, and Im having a hard time coming up with an acceptable answer.
The main issue is a conflict between

An extract is “cast” by drinking it, as if imbibing a potion

and the communal spells/extracts such as darkvision and delay poison

Target creatures touched

There is also

In effect, an alchemist prepares his spells by mixing ingredients into a number of extracts, and then “casts” his spells by drinking the extract. When an alchemist creates an extract or bomb, he infuses the concoction with a tiny fraction of his own magical power—this enables the creation of powerful effects, but also binds the effects to the creator

The alchemist is clearly given the communal spells because of the formula list, but the question is more about how to have it take effect. Does he drink part of his extract then pass it around? Does he swish it around in his mouth and spit it back into the flask for the others? Does he drink and touch people? Does he shake the flask and spray it around like Champlain?

The class for the most part seems pretty specific that whatever the alchemist makes is for themselves (baring the infusion discovery). So how do the communal ones work?

Best Answer

The alchemist can't normally give extracts to others, even if the spell it's based on has a range of “touch”:

Alchemy (Su)

[…] An extract immediately becomes inert if it leaves the alchemist's possession, reactivating as soon as it returns to his keeping—an alchemist cannot normally pass out his extracts for allies to use[.]
[…] the effects of an extract exactly duplicate the spell upon which its formula is based, save that the spell always affects only the drinking alchemist[.]

So when an alchemist makes a darkvision or delay poison extract, the extract is usable only by the alchemist who made it.

To allow others to use her extracts, the alchemist must have gained the Infusion Discovery via the usual rules for gaining Discoveries.

Knowing the Infusion discovery would also allow the alchemist to make one extract of darkvision, communal and pass it around so everyone can have a sip (1 hour duration per sip), instead of having to make many normal darkvision extracts for each party member.