USDA recognizes 3 Grades of Butter- AA, A and B; determined by highly trained graders utilizing strict United States standards. All grades meet consumer requirements. AA being the hightest/best in butter flavor, smoothest in texture, the best choice for cooking, baking and at the dinner table.
The U.S. grade of butter is determined on the basis of classifying first the flavor characteristics and then the characteristics in body, color, and salt. Flavor is the basic factor in grading butter and is determined by taste and smell.
Refrigerate at 45°F or below. Best if used by the printed use by date.
Midwest Dairy Association
Data credit 1
USDA Ag Marketing Service