Millstones, bolting, and flour grades
Stone milling fractures endosperm along natural fault lines, whereas steel rollers shear progressively finer layers. Canadian bakers historically requested straight grades tied to ash content—the mineral residue left after incinerating flour samples.
Stone provenance and dress
French burrs shipped as quarried segments bolted into balanced runners. Eastern mills imported pairs through Montreal warehouses while Prairie operators sometimes reused worn runners for cattle feed grinding. Dress patterns balance furrow count against throughput; dull stones heat flour and darken ash readings.
Bolting cloth and particle bands
Sieves woven from silk or synthetic meshes separated bran from middlings. Mesh counts increased toward patent flours used in pastry. Bolting-room humidity mattered as much as stone sharpness: damp silk blinded faster on Atlantic coastlines than in drier Calgary milling rooms.
Relating ash to wheat hardness
Hard red spring wheat tolerates aggressive milling without collapsing loaf volume; softer eastern wheats demanded lighter roller gaps. Cross-read seasonal race notes in water-driven grist mills with aeration hazards from Prairie wind contexts to understand regional blends.
Authority references
Detailed stone geometry diagrams remain in nineteenth-century engineering manuals digitized by Government of Canada open-data portals and overseas library scans cited inside Commons file descriptions.
Mechanical diagrams reference the flour article for baseline terminology.