Fermenters are base structures used for fermenting mead and wine bases into meads, potions and wines.
They require a roof and 70% cover to function. Destroying a fermenter won't return back the mead or wine base.
The Cauldron can be used to brew mead bases, which are fermented into mead. Each mead base results in 6 finished products.
A fermenter cycle takes two in-game days.