Email response from King Arthur Flour about the types of wheat they use

Thank you for your email. Our Flour Sales Support team has responded as follows:

There are three main wheat boards: Minneapolis (Hard Red Spring Wheat,
which is used in our Bread, Whole Wheat), Kansas (Hard Red Winter Wheat
which is used in our All Purpose Flour) and Chicago (Soft Red Wheat,
which is used for pastry and cake flour). Our White Whole Wheat is
Hard White Spring Wheat, but for pricing purposes our contacts use the
Hard Red Spring Minneapolis Board. The two most influential boards seem
to be Chicago and Kansas, due to volume. Minneapolis is the smallest
board due to the fact that they have the smallest volume of wheat. Many
factors affect price; amount of wheat available, overall money being
poured into commodities (like wheat, corn, soybeans, oil, silver, etc.),
a weak dollar compared to the rest of the world (making our products
less expensive to other countries).