The warm temps and beautiful days of true Spring also mark the end of maple sugar season here in New Hampshire. As much as I enjoy the sweet smell of evaporating sap, I am also happy to see the season end. The long days and late nights by the evaporator can be exhausting. This year, we made a little bit more than 1 gallon of syrup. Our smallest take in four years. This is mostly due to tapping a fraction of our sugar bush. Given all of the projects my family has in the works, this was one thing we could downsize. In addition to that, this was not a good year for maple syrup. The season began late, was inconsistent and the weather was unforgiving. For the first time, New Hampshire Maple Weekend came before we even tapped our trees.
The bulk of the work making maple syrup is in evaporating all the water. Sap is only 1.5 to 2.5% sugar. Syrup is 66% sugar. So it takes about 40 parts sap to make just 1 part syrup. To get the evaporator going we really need at least 25 gallons of sap and more is better. Without ample sap to keep replenishing what is evaporated we run the risk of damaging the pan and worst yet burning the syrup. There is not bigger mess than an evaporator pan with burnt syrup, it is a truly awful thing to clean.
This Spring began with a false start, a warm day followed by many cold days. Because of this, by the time we had enough sap to run the evaporator the sap had already gone bad. Sap is perishable, unfortunately.
The first time we tapped trees I was surprised to see the hole where the sap enters the tap is on the bottom of the tap. I always thought sap dripped down, with gravity. Sap is actually pulled up from the roots of the tree, through the trunk about a 100 feet into the air and out to the branches. How does a plant with no muscles and no brain achieve such a feat? The answer is pressure. Overnight temperatures below freezing and daytime temperatures creates negative pressure and temps. above freezing creates positive pressure. In addition the sapwood contains carbon dioxide which contracts when it's cold and expands when it's warm, creating pressure. Finally the presence of sugar in the sap creates osmotic pressure. All three of these natural forces work in tandem to delivery the sap (created from photosynthesis in the previous summer) to the branches to make leaves to again make sap. Truly an amazing process for a hunk of a wood.