The soldiers' grains were rationed and distributed centrally as a food staple. The grain was ground fresh in the hand-held mills and usually used for porridge or flatbread.

The grinding stones consisted of the bottom stone ("meta molendaria") and the "catillus" on top, which was moved with a wooden hand-crank. The mills had a diameter of up to 40cm and were made of hard stone such as granite or basalt. The grinding stone in Museum Bürgstadt is made of basalt magma.