How about normal Windmills? I'm dutch and have a hard time living in this world that provides me with clogs but no windmills (or tulips...)
The way I'd envision a grain/mill to work is kind of like how it worked in runescape (awefully dull game that is...) You put grain in one end, and flour comes out the other. The main advantage this is over the Quern, is that you dont repeaditly have to press the craft button to get your flour. Instead you only have to open an inventory screen and fill it up with grain. kind of like... how the Herbalist table works

instead it would have an input inventory, and an output inventory.
querns would still be usefull for those who do not have the skill to build a mill, or do not wish to invest into a mill.
Perhaps there could even be a "Windyness" upgrade to the UI aswell, so that windmills wouldn't always work maybe even going as far as having a wind direction, Most windmills have a rotatable topside asfar as I know.