Flour strength and Manitoba flour

The alveograph, built by Marcel Chopin in 1921, inflates a sheet of dough into a bubble and records the pressure. The curve yields P (tenacity), L (extensibility) and W – the area under the curve, corresponding to the energy needed for deformation, somewhat loosely called flour strength. The P/L ratio shows the balance between tenacity and extensibility; 0.40–0.70 is considered ideal. Below 0.40 the dough is too extensible and sticky, above 0.70 too tough; either way the bread rises poorly.

A strong flour with high W retains carbon dioxide better during long fermentation; for long proofs a W of roughly 250–320 is suggested. Low-W flour suits sweet baking with short rising times. Strength depends not on the type (00, 0…) but on gluten, and it is rarely stated on the bag.

Manitoba takes its name from the Canadian region where strong wheat varieties originated; they are now grown in Europe as well. In Italy the name is used for flour with W above 300, intended for panettone, colomba and other large leavened cakes. The term does not appear among the legal flour types of Presidential Decree 187/2001.