Actually it's graded SOLEY on its color. The darker the color the stronger the maple, earthy taste, and usually the later in the season it's harvested. The lighter color, grade A, is closer to what we think of as table syrup, slight maple, woodsy flavor, but doesn't taste like your chewing on a green twig.The grade A syrup is more refined. Not sure exactly how it’s done, @WthrLady could chime in. The grade A is a lighter color and what is sold in grocery stores. The grade B is dark and has a richer flavor to me. I think it has to do with how long it is simmered.