Barrel

A  is a storage structure used to store liquids.

Barrels can be stacked up to 3 high, like most storage structures. One barrel usually stores 100 units, and stacking more barrels will expand the available storage to 240 and 400 units respectively.

After researching Bigger Storage, 3 stacked barrels can be upgraded to a Cask by using  to access the update/info panel.