What is Maple Syrup?
Maple syrup is made by reducing the clear sap from maple trees into a high concentration sugar suspended in water. When the maple sap is harvested, it is a watery liquid (not thick, sticky, and viscous like other saps we are familiar with). This sap mostly water, about two percent sugar (with some impurities). The sap is then boiled until much of the water has evaporated. During the boiling, impurities rise to the top and are skimmed off (like making a stock). Once enough water has evaporated so that the sugar content exceeds 67%, the sweet liquid is considered maple syrup. The lightness of color and strength of flavor is dependent mainly upon when the maple syrup was harvested and the weather and growing conditions of the maple trees for that year. Typically, lighter syrups are harvested earlier in the season.
The United States Department of Agriculture (USDA) assigns grades to the maple syrup sold in the the U.S. These grades are: Grade A Light Amber, Grade A Medium Amber, Grade A Dark Amber, and Grade B. The grading of syrup sold in the United States is voluntary (like USDA Beef Grading).
Grade A Light Amber (or Fancy) is very light in color and has a faint, delicate maple flavor. It is usually made earlier in the season when the weather is colder. Many people use this grade for serving on pancakes. It is also widely used for making maple candies.
Grade A Medium Amber is darker and has an easily discernable maple flavor. I like using this grade for serving on pancakes and waffles. I also use it for baking since it has a stronger flavor than Light Amber.
Grade A Dark Amber is very dark and has a strong maple flavor. Some people like the stronger flavor and use it as a table syrup, but this grade is mostly used for cooking and baking.
Grade B, sometimes called Cooking Syrup, extremely dark in color and has an extremely strong maple taste as well as hints of caramel. Because of its strong flavor, this s predominantly used in baked goods.
Maple syrup should be refrigerated to ensure freshness (even if the bottle hasn't been opened). You can also freeze maple syrup to extend its life indefinitely. If the syrup is refrigerated in glass containers, then the syrup will maintain quality for a year. Plastic bottles are a little porous, so refrigerator shelf life is usually around three to four months. If you need to store syrup purchased in plastic bottles for longer term storage, pour it into a glass bottle or jar and refrigerate.
Use as a sugar substitute
In general, maple syrup can be substituted for granular sugar in baked goods by following these rules of thumb:
For each cup of granulated sugar, use 1-1/2 cup of maple syrup.
Reduce other liquids in the recipe by about one-half.
Add 1/4 teaspoon baking soda for each cup of maple syrup.
Decrease oven temperature by 25°F.
Most syrups sold as pancake syrups are not maple syrup. These syrups are made of either cane sugar or corn syrup and contain a few percent of maple syrup for flavoring. Real maple syrup has a more robust flavor and (as my wife says) tastes less man-made.