Another explanation I got from a Lithuanian is that, in the past, beer was used mainly as food. This was because the millstones were flaky and so you would end

Another explanation I got from a Lithuanian is that, in the past, beer was used mainly as food. This was because the millstones were flaky and so you would end up with bits of stone in flour. Not great for the dental work. If you brew beer then the bits of millstone settle to the bottom.