Halflings can stuff their cheeks like hamsters. It looks really gross.
Dwarves are immune to alcohol poisoning and can’t actually get drunk; “dwarven ale” is an elaborate and improbably successful practical joke.
Elves have a part of their brain devoted to detecting sarcasm.
Orcs respond to umami/savory flavours the same way that humans respond to sweet ones; the taste of cheese is mildly addictive to them.
Gnomes can smell fear.
Additional headcanon: Dwarven ale is intoxicating, just not alcoholic. Thus very few non-dwarves except for a couple of subterranean-themed druids have any kind of tolerance for the real kick of dwarven ale.
Alternatively, dwarven ale is indeed fermented to the Nine Hells and back (helps it keep forever), but the extra, nonalcoholic intoxicants are what really make it fun for dwarves and enough to knock non-dwarves on their arse.
Also, what kind of environmental pressures caused elves to evolve a part of their brain capable of detecting sarcasm? The forests where the elven species first arose must be full of passive-aggressive animals.
Hey, if you think it’s annoying having to travel through an enchanted forest, imagine growing up in one! Between the pixies, the satyrs, and the oddly well-dressed rodents, you can’t even go to the bathroom without some capering dipshit turning it into a moral referendum. Oh, you wanna play a game? Okay - riddle me this, you jig-dancing fuck.
