The Bug
Taking out any item besides a water bottle in a brewing stand will give you the "Local Brewery" achievement.

Reason
The method net.minecraft.inventory.ContainerBrewingStand.onPickupFromSlot(playerIn, stack) only checks if the items PotionType is not water. This means any other item will work. This can be fixed by also checking if the item is either a potion, splash potion, or a lingering potion.

Old description:

I had killed a witch and obtained some glass bottles. Having no empty chest space, and being too lazy to make a new chest, I simply stored them in a brewing stand. Later, when I went to withdraw them, I was greeted with the "Local Brewery" achievement upon taking them out, despite not having brewed anything yet. EDIT The bottles were empty.