I feel like it would be the same as countries outside the US: If you can reach over the bar to order, you’re allowed to drink.
So it must really suck to be a gnome or halfling.
Ah, yes, “outside the US”, where there are no laws…
Everywhere I’ve personally been outside the US either didn’t have or at least didn’t enforce any age for purchasing alcohol.
For reference, those countries were Ireland, Germany, Mexico, France and Canada.
That’s not even what happens here though. Just because you can drink in Canada at 18 doesn’t mean I can go to the States, you’ve gotta be 21.
Not really a good analogy, because the age at which you can drink is based on where you are, not in where you were born etc. An American 18 year old could go to Canada or well pretty much anywhere else in the world and they can get as drunk as they like.
age is based on where you are, not in where you were born
Age is based on when you were born, not where you were born, unless if you were born orbiting black hole /j
Different species may have different ages of brain maturity at which point alcohol won’t pose as much of a risk of stunting their mental development. Elves for example settle into adulthood at around 100 years of age.
So a responsible legislature would codify in its laws what the minimum drinking age is for each species based on science’s best understanding of their physiology.
Dragons don’t really ever stop growing, although if there’s one in your bar you have much bigger problems.
So we are ignoring jurisdiction? … Well… even if we ignore the possibility of an infinite universe, tracking hundreds of thousands of legal systems and species biology (what is intoxicating to whom, the cognitive self-development thresholds, how much of a substance one may serve to whom) and being able authenticate/verify an ID (we have photo-ids, but maybe others are different)… like a slime-species that identifies each other by smell… or taste… I’m confident that for any interesting set size, this would actually be an unsolvable problem.
Take it even farther, not all species get hammered on the same chemicals. “Barkeep, a glass of your finest room-temperature-aged milk, please!”
This concept goes so well in a spelljammer like setting. Imagine the Laughing Beholder with large Luigi doing this. “Okay, what sphere are you from again? Okay, next I need your planet, then your species, then your age.”
EDIT:
Noncombat or low combat adventure idea that just came to me based on this. A group of grifters has conned Large Luigi or your version of this bar owner by posing as an interplanetary or interplanes alcohol enforcement agency. They pulled a fake sting and made off with something precious of the innkeepers as a fine. The party either hears this from the barkeep when they order or from the other patrons who are fed-up with the arcane ID system and long waits on drinks. Only recovering the fine or capturing the grifters can the situation be set right.