Wheat varieties are called "clean," "white," or "brown" or "hard" if they
have high gluten content, and they are called "soft" or "weak" flour if
gluten content is low. Hard flour, or bread flour, is high in gluten, with
12% to 14% gluten content, and has elastic toughness that holds its shape
well once baked. Soft flour is comparatively low in gluten and so results in
a finer or crumbly texture.[1] Soft flour is usually divided into cake
flour, which is the lowest in gluten, and pastry flour, which has slightly
more gluten than cake flour.