Some Background: Hard Red Wheat vs Hard White Wheat
Hard white wheat was developed from hard red wheat by eliminating the genes for bran color while preserving other desireable characteristics of red wheat. Depending on variety, red wheat has from one to three genes that give the bran its red cast; in contrast, white wheat has no major genes for bran color. The elimination of these genes results in fewer phenolic compounds and tannins in the bran, significantly reducing the bitter taste that some people experience in flour milled from red wheat. Nutritional composition is the same for red and white wheat.
Spring wheat is planted in April to May, makes a continuous growth and is harvested in August to early September. Winter wheat is planted in the fall. It makes a partial growth, becomes dormant during the cold winter months, resumes growth as the weather warms and is harvested in the early summer (June and July).
Flour from hard red winter wheat is often preferred for artisan breads.