|“I have never tasted any better sugar than what has been made from the maple, when it has been properly refined. It has a peculiarly rich, salubrious, and pleasant taste.”
- Samuel Williams, A Natural and Civil History of Vermont 1794
|How Maple Syrup is Made|
In January, we head into the woods to prepare for sugaring season. Each year we inspect the lines, adding new taps and replacing old ones, inspecting the pipeline system for damage and making the necessary repairs. Although we still hang a few buckets around the sugarhouse, they aren’t used much any more. Most sap collection today is done through systems of tubing and pipeline.
As we anticipate warmer days, we begin tapping. To tap a tree a small hole, generally between 3/16” and 5/16” in diameter, is drilled. A spout is then gently tapped into the hole. On our farm we have approximately 11,000 taps, so this process is repeated approximately 11,000 times each year. Some sugarmakers with whom we work have as many as 90,000 trees to tap each year. The goal is to have the woods tapped before the first good "run" (sap flow), though that’s only the beginning of the woods work – during each run the lines will be checked for leaks, sap is precious.
Determining when that first run will happen is nearly impossible, and as you can imagine several schools of thought have developed over the years. The challenge in deciding when to tap is that you don’t want to tap too early because the tap hole will dry out over time and eventually stop running sap. You don’t want to tap too late because the season for making maple syrup is short and once you’ve missed a good run you can’t get it back. On our farm by the end of February we've usually had a good run and made our first batch of syrup.
Many sugarmakers with tight tubing systems now employ the technology of vacuum in their operations. Though it sounds like we might be sucking the sap out of the tree, we’re not. Maple sap flow dynamics is complicated and research has yet to fully explain how it completely works. However, one function of sap flow that we do understand fairly well is the influence of pressure. Changes in temperature are what generate sap flow by causing pressure to develop in the tree (that’s why cold nights and warm days are described as good sugaring weather). If we don’t have ideal temperature changes the tree pressure is very low and sap barely flows. By applying vacuum we are essentially changing the atmospheric pressure at the tap - we are allowing a more favorable environment for the sap to run. In other words, vacuum can’t make sap run when it wouldn’t normally, but it can help extend a run.
Once the sap has been collected it is boiled. Generally, sap has between 1.5% and 3% sugar content and the process of boiling evaporates away water, concentrating the sugars. Sap officially becomes maple syrup when it reaches a density of 66.9 Brix. The process of boiling caramelizes the sap sugars and concentrates the subtle maple flavors.
It takes approximately 40 gallons of sap to make one gallon of syrup. The amount of sap exactly required to make one gallon of syrup is related to the sweetness. The sweeter the sap the less it takes to make one gallon of maple syrup. Jones rule of 86 says that: If you divide the sap sweetness into 86 you get the exact number of gallons to make 1 gallon of syrup. Thus, it will take 86 gallons of sap with 1% sweetness to make a gallon of syrup and only 17 gallons of sap at 5% sweetness.
Recent developments in the technology of reverse osmosis have allowed sugarmakers to increase the sweetness of sap before boiling reducing the amount of fuel required to make syrup. Reverse osmosis is the process of pushing sap through very fine filters at high pressure. The filters allow water particles to go through but not sugar and mineral particles. Reverse osmosis is a technology generally used for desalination.
Once syrup has been drawn off the evaporator it is hot filtered and pumped into 35, 40, or 55 gallon drums or canned up in retail containers for farm-gate sales.