How do Oast houses work? (I think I’ve spelt it right) I know they were designed to dry the hops. Most of them in my area have been converted into homes but still maintain the funnelled roof. Those that are completely intact have a sail or a vane on the open side of the funnel which suggests that this opening is turned away from the wind. Up until now, I thought that the wind or air stream was collected by the funnel and blown down over the hops. Obviously not?