Maple syrup grades have nothing to do with quality or nutrition. Instead, they simply refer to the color of the syrup, and thus, its flavor.
The lightest and mildest syrups, which are generally harvested at the beginning of the season, are called "fancy grade A" or sometimes "grade A light amber"; At the middle of the spectrum are "grade A medium amber" and "grade A dark amber."
Finally, there's "grade B", the dark, thick syrup that packs a strong maple punch with caramel undertones. It's also called cooking syrup, as it is more commonly used for cooking and baking, rather than serving at the table with a stack of flapjacks.
As the Massachusetts Maple Producers Association says,
It's strictly a matter of personal choice. Ask yourself these questions: Which is better, white wine or red wine? Which is better, light beer or dark beer? Beer can probably be compared most easily to the different maple syrup grades/flavors. A light Pilsner beer has a light color and delicate flavor, while a Stout or Porter has a very dark color and strong flavor. It's strictly a matter of personal choice, and there isn't one grade of maple syrup that is "better" than another.
We've been pouring the grade B on our pancakes for a couple of weeks now, and find that we need far less syrup (thereby consuming less sugar). Grade B will make your baked goods more maple-y, and it's sensational in ham glazes.
Until recently, it was hard to find grade B, as it was primarily sold to manufacturers. But we've found grade B at farmer's markets, Whole Foods, Trader Joe's, and King Arthur Flour.
We've got a stack of baking on our to-do list (what a problem to have!) but we're still thinking about Laura Ingalls' maple candy.
What grade of maple syrup do you have on your breakfast table?