The season for making maple syrup is five to seven weeks in March and April. It begins when the snow is still deep and the days start to warm. Through the season, the freeze-thaw cycle is like a pump for the sap. When days and nights become warm, the season is over. The temperature also changes the flavor and color of the maple syrup, mostly due to fermentation of the sap.
The warmer the temperatures, the faster the fermentation in the sap. Maple syrup contains over 200 compounds that we can smell and taste. The raw ingredients for those come out of the tree and are transformed by microbes that occur naturally in the environment and by boiling the sap to concentrate it.
If you've made bread or beer, you know to add different ingredients in very specific amounts. You've let bread rise in a warm place for a certain amount of time and go through a similar process with beer. With maple, we add nothing -- the ingredient is just what nature provides. We do not control quantity: We get as much sap as runs that day. We do not control time: The sap starts to run when it does and with small and medium sugaring operations, we boil when we get home from day jobs or whenever we can. We do not control temperature. How warm did it get that day? Was there full sun or was it overcast?
It is a wild process that produces changes in the syrup color and flavor.
Early season, maple syrup is light colored and has a delicate flavor. Sometimes it is as clear as water, but most often shades of gold. It has subtle flavors and what I call high sugars -- like marshmallow or confectionary sugar.
Mid season, the color's amber and the flavor is rich and complex. There is a base of maple and caramel with notes of vanilla, melted butter, smoke, and honey. There also are hints of cloves and hazelnuts, and sometimes apple, peach, rose, coconut and even pineapple. All from sap from maple trees! Crazy, right?
Late in sugaring season the days can be quite warm -- sometimes into the 70s (over 20°C). Late harvest maple syrup color is dark (i.e., a deep rich red-amber). The flavor is not as complex as mid-season, but it is more intense. I've described Vermont Maple dark as a freight train of maple with boxcars of caramel and melted butter. It has a long finish that keeps going and going, fading without losing any of its delightful character.
In 2021, we had molecular analysis (mass spectrometry and gas chromatography) done of our Amber and Dark maple syrup by a Belgian company. After learning which aromatic compounds are in Vermont Maple syrup, I read over 50 scientific papers and scoured the web to find out the origin of each. Does a compound come out of the tree, is it created during fermentation, does it happen during boiling? What choices can we make as sugarmakers to produce maple syrup with unexpected flavors that delight the senses?
This means that we are not simply trying to make syrup taste like my Grampa Howard made. We can discover new methods to make more amazing and intense aromatic notes using only what nature gives us.
One of the big questions is whether we should blend batches of syrup so that it has a uniform color and taste season after season. Or perhaps we should let every batch stand alone to highlight its unique and delightful flavors. We want customers to taste their food, so we have decided to present variation and nuance as an inherent part of the experience of maple syrup.