Beer is a liquid that can be used as fertilizer in Trays. Additionally it's used by Precursor Spawner as fuel.
This liquid doesn't exist as lakes/puddles anywhere. Precursor Beer Generator allows you to quickly produce Beer in potentially infinite quantities, but it stops producing if you have 1000 or more Beer in your inventory. The process can be automated by filling your inventory with anything except Beer and placing a few Grabbers near by - it will still stop working if you stand AFK for too long, though.
How to obtain
Crafting
Animals
Used for
Crafting