Maple Season: New Hampshire's First Rite of Spring

March is maple sugaring time in New Hampshire. This uniquely North American natural phenomenon is not restricted to the calendar like school vacations, holidays or town meeting day, but is dictated solely by day-night weather changes. Cold nights in the 20's followed by warm days when the temperatures go up into the 40's, absent a chilling wind, are the requirements for the sap to run.

Our sugaring season can begin in late February and run into early April and even stop in between. Although sugaring season does coincide with mud season, no one knows how long the season is going to be until after it's over.

Tapping the trees
Although some maple producers still use the traditional bucket-with-spout-and-cover system for tapping their trees, others use high technology plastic tubing and pipeline systems, some of which include vacuum extraction to increase the amount of sap collected. This doesn't hurt trees and keeps the sap-lines empty which helps produce a higher quality sap for high quality maple syrup.

Today's maple producers are also using "health spouts" to lessen the impact of tree-tapping. With the new spouts, trees now heal over in less than one growing season. Regardless of the method of gathering sap, it must be collected after each run and boiled as soon and as fast as possible to make the best quality maple syrup.

Note: “Maple producer” is the modern name for what used to be called a “sugarmaker” in the days before containers became commonplace and most syrup was boiled down to the hard sugar for long storage.

Boiling down
Sap is boiled down in an evaporator, a special pan with flues in it to increase the surface area and speed evaporation. Boiling down has and continues to be the challenge of maple producers everywhere. Before the evaporator was invented, sap was boiled in a series of open kettles, and before then in hollowed out logs with hot rocks dropped in to evaporate the sap.

While some maple producers continue to use open evaporators similar to those that made their debut in the 1880's, others have embraced new technology. Peering inside a modern sugarhouse, a visitor will see an array of sap-processing equipment that may include evaporators with steam hoods, blowers and pre-heaters, and steam-away pans mounted atop a conventional evaporator, using recaptured steam heat to increase the efficiency of the boiling process. These latter systems look more like large boilers in ships than those traditionally found in the sugarhouse. In larger operations, visitors may encounter reverse-osmosis machines that concentrate the sugar content in the sap for later processing in an evaporator. Steam evaporators are also becoming more commonplace.

Maple sap is about 97.5 percent water, 2.4 percent sugar, and 0.1 percent minerals. Sap is made into maple syrup by boiling off the water and concentrating the sugar and minerals in the presence of heat. During the process of evaporation heat causes chemical reactions in the concentrated sap resulting in the characteristic flavor we know as maple syrup. The color and flavor of maple syrup is determined by the freshness of the sap and the speed of boiling.

Pure maple syrup must have a minimum density of 67° Brix, equivalent to boiling maple sap until it is 7.5°F above the boiling point of water. Proper density is important, not only for taste, but also for stability, preventing the syrup from forming crystals or fermenting.

It takes about one cord of dry wood to make 20 gallons of maple syrup. Oil-fired evaporators are gaining in popularity, as they tend to be more efficient and relieve maple producers of the work of cutting wood. It takes about 40 gallons of sap to make one gallon of syrup.

Grading and packaging syrup
Maple syrup is governed by State law with respect to density, color, clarity and flavor. Sap becomes syrup when it reaches a density of 67° Brix at 60°F. Syrup at this density consistently boils at 7.5°F above the boiling temperature of water (around 219 to 220°F). During evaporation minerals appear as a sediment known as "sugar sand" or "niter" and are removed by filtering, resulting in a crystal-clear product. Syrup is then packed hot, between 180°F and 190°F, into glass, tinned steel or plastic containers. The hot syrup sterilizes the container to prevent the syrup from spoiling. Whether opened or not, maple syrup should always be kept refrigerated if possible.

Maple syrup is graded by color, flavor, and clarity. All table syrup is Grade A and all syrup must be the same density. Grade A-Light Amber maple syrup is "light" in color with a delicate flavor and requires considerable skill to make. It is usually made from the earlier runs when the sugar content is highest and daytime temperatures keep the sap cool. Grade A-Medium Amber has a richer flavor and Dark Amber, popular for cooking, is even stronger. Pure maple syrup contains no additives or preservatives.

Maple syrup is made into several other products by boiling it beyond the syrup stage in conjunction with other procedures (stirring, cooling) to produce taffy, cream, candy and sugar. Nothing is added, the end product is pure maple. These products are usually made from the light- and medium-colored syrups.

Syrup-making: Our first rite of spring
The maple season is an age-old tradition, part of our rural heritage. Stop by a sugar house—the sweet steam coming out the roof vent is your invitation to go in and visit. Even on chilly nights when the sap is being boiled, the evaporator provides warmth with the pleasant aroma of maple syrup in the brisk night air.

To find a sugarhouse to visit or to purchase maple products, contact the N.H. Maple Producers Association or call the NH Maple Phone at 603-225-3757 for sugarhouse brochures and information about Maple Weekend, March 21-22, 2020.

Nominate a young N.H. maple producer for the Felker Award
The Walter A. Felker Memorial Award encourages interest by New Hampshire youth in the Granite State’s great maple sugaring tradition. The competition is open to New Hampshire residents younger than 16 years of age by the June application deadline.

The award winner receives a permanent plaque engraved to recognize their achievement as well as a $300 cash prize. Read more about the criteria and application for the Felker Award.


Steven Roberge
Extension State Specialist, Forest Resources
Assoc State Spec Professor
Phone: (603) 862-4861
Office: UNH Cooperative Extension, Taylor Hall, Durham, NH 03824