25
Dropped by
a melee weapon that behaves like a gun
It burns Ale as ammunition and takes ranged reforges, and it is the only melee weapon in the game that does either. Unreal is the roll you want, which is not a sentence that applies to any other sword. It also usually keeps the bottle it just threw, so a modest stock lasts far longer than the throw rate implies and resupply is rarely something you have to plan around.
aim at the ground, not at the enemy
The bottle arcs, shatters on the first thing it touches and soaks a square of tiles around the impact. Each additional enemy caught in that same burst takes less than the one before it, and a direct hit counts as the first link in that chain. The practical consequence gets missed: hitting an enemy in the face spends the full share on that one body and drops everything else in the pack a tier down. Throw at the floor beside a group instead and the burst starts from full on whatever it reaches, which is more total damage out of the same bottle.
the debuffs cut both ways
Enemies caught in the splash can come out confused and wander off, which is worth something against anything that closes on you. Everything hit ends up tipsy, and that includes players and town NPCs. Tipsy is a straight upgrade on an NPC, raising defense and damage and quickening their attacks, so soaking your own townsfolk before an invasion is a deliberate play rather than friendly fire. Drinking it yourself is also one of the standard ways to reach an early melee speed benchmark.
getting one means killing the Tavernkeep
It only drops from the Tavernkeep himself, and a town NPC cannot be hurt by you directly, so the kill has to come from somewhere else. The Flymeal is the least fiddly option and the Classy Cane works the same way. Traps, Explosive Bunnies, Land Mines, boulders, lightning, drowning and simply letting an enemy reach him all do the job. Lava works too, with one warning: a pool deep enough will burn up low rarity drops before you can collect them, so keep it shallow.
what melee speed does here
Not what you would expect. Speed bonuses make the bottle fly faster and flatter, which helps you land it where you aimed at range, but they do nothing to how often you can throw. The chance of keeping a bottle was picked for the joke in the number rather than for balance, which is worth knowing before you build a run around the ammo economy.