The vast majority of today's flour
consumption is wheat flour.
Wheat varieties are typically known as 'White' or Brown
if they have high gluten content, and soft or weak flour
if gluten content is low. Hard flour, or "bread"
flour, is high in gluten and so forms a certain toughness
which holds its shape well once baked. Soft flour is
comparatively low in gluten and so results in a finer
texture. 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.
All-purpose flour is a blended wheat flour with an
intermediate gluten level which is marketed as an acceptable
compromise for most household baking needs.