Have you ever wondered why there are different colors of maple syrup when there is only one ingredient in them? With the good stuff, the label will grade the syrup from AAA to B, and on extreme rarities grade C. This grading system doesn't rate one above the other, instead it separates the syrups into categories of color and flavor.
Because the syrup depends greatly on the weather, it can only be harvested a few weeks out of every year. During the day the temperature must be above freezing and during the night it must be below freezing. After a tree is tapped its sap will start to flow. this sap is mostly water. It is so dilute that it will take 40 gallons of raw sap to make one gallon of usable syrup. The first grade to come out in a season is AAA this is the lightest of all, also it is the sweetest. However it is also the least maple flavored. As the temperature raises day to day the trees gradually start using their sugar for food, and start producing more sap. This occurrence is what causes the difference in color and flavor in the syrups. In the late season, when the nights are no longer going below freezing, the syrup will be very dark and full maple flavored, but it will be nowhere near as sweet as the early stuff.
All of this also applies to birch and palm syrup as well, but these trees are more scarce and also produce much more dilute sap, which is why they are hardly ever seen at market.
