I find that stockpiling drinks in the tavern to be a bit annoying when they start overflowing and you have to delegate them to another stockpile outside the tavern. So I was thinking; what if we could build giant kegs that can hold a large volume of drink that you can place in your tavern and tavern keepers and thirsty dwarves will fill drinks using it so you don't have a crummy stockpile with a hundred barrels littering your tavern.