An Introduction to Sugaring

Throughout the northeastern US and eastern Canada, the term "sugaring" is often used to describe all of the activities associated with the production of maple syrup. The term is even used to describe the season of the year (from mid-February to mid-April) when the sap of the sugar maple is collected and boiled to create that delicate confection.

The Maple Region

The commercial product of maple syrup only occurs in the northeastern US and eastern Canada, within the natural range of the sugar maple. Other species of maple will produce sap, which can be made into maple syrup (black maple and red maple are also commonly tapped), but sugar maple sap generally has the highest sugar content and yields the most maple syrup, per gallon of sap boiled.

Weather patterns also play a critical role in the production of maple syrup. Maple trees only produce commercial quantities of sap in regions where, during late winter and early spring, freezing nights (250 F or below) are followed by warm days (400 F or above). The science behind sap flow is complex, but as maple trees begin to warm-up on these pleasant spring days, pressure builds within the tree, and sap is literally forced from any small wound or tap-hole in the tree. In Vermont, the conditions are often right for the sap to "run", or flow, from mid-February to mid-April, but during this period "sap runs" (the period of time when the sap actually drips from the tree) may only occur five or six times. Depending on the weather, "sap runs" can last from a few hours to several days.

Maple Sap Production

The size and complexity of "sugaring" operations varies greatly throughout the maple industry, but the basic process of harvesting sap from maple trees (tapping) is common to all. Trees that are twelve inches in diameter and larger are selected for tapping. Shallow holes are drilled, into which metal or plastic taps are firmly seated. Years ago, wooden or metal buckets would have been hung on these "spouts", and once filled, would have been "gathered" into tanks on horse-drawn sleds and transported to the "sugarhouse". Some "sugar makers" still use metal buckets, and gather sap by hand, but it is much more common to see plastic tubing used to transport sap directly from the tree to the sugarhouse or a storage tank.

Making Maple Syrup

Maple sap, as produced by the tree, is mostly water. To produce maple syrup, a large amount of this water must be boiled-off and the sugars concentrated. An often-used rule of thumb states that roughly 40 gallons of sap is required to produce just one gallon of maple syrup.

Early settlers often used iron kettles hung over a wood fire to boil sap, but over the years, specially designed maple "evaporators" or were developed to increase the speed and efficiency of the boiling rocess. The evaporator uses an enclosed firebox, or "arch" and large, flat pans with flues (deep channels or flutes in the bottom of the pan) to increase the heat exchange area and speed the rate of evaporation. Wood has traditionally been used to fuel maple evaporators, and is still used by a great many sugarmakers. However, other fuels such as oil and propane or natural gas are increasingly common. Today's sugarmakers continue to employ new and innovative technologies to improve the efficiency of the boiling process. Evaporator designs are constantly changing to make better use of energy and to speed th boiling process. Many sugarmakers are also adopting new technologies, such as reverse osmosis (the process of partially concentrating sap by passing it through a membrane through which water molecules will pass, but sugars will not).

Sap is boiled until it reaches the required density for maple syrup. The syrup is then "drawn-off" into a stainless steel pail, or other container, for a final check of density, filtering and bottling or canning. A sample of each batch of syrup is also taken and assigned a maple syrup grade, based on its color and flavor. Once packed in retail or wholesale containers, properly graded and labeled, the syrup is ready for sale.