Production

Maple syrup production is a unique and tasty spring tradition in the Great Lakes and Northeastern regions of the United States and Southeastern Canada. While the science of turning maple sap into syrup is simple, the process is time consuming and relies heavily on specific weather conditions.

Throughout the summer months, trees and other plants are using the green chlorophyll in their leaves to convert sunlight, carbon dioxide, and water into oxygen and sugar, a process called photosynthesis. The sugar mixes with water to create sap and flows through the inner layers of the tree, fueling the tree’s growth. When the leaves begin to change color in the fall, the sap flows into the roots and lower trunk of the tree, where it is stored for the winter. In the spring, warmer temperatures cause slight pressure changes in the inner layers of the trees, pulling the sap up from the roots to the branches to feed the developing leaf buds. This time in the early spring before the new leaves burst from their buds is when sap can be collected for syrup production.

Although all plants produce sap for their own food, not all sap can be turned into food for humans. Sugar maples, red maples, and silver maples all have a high enough sugar content in their sap, averaging 1% - 3%, that the sap tastes sweet when boiled. Other trees produce sap with a bitter taste or sap that is poisonous, such as the sumac tree. Identifying a maple tree is the first step to producing delicious syrup. Sugar maple leaves are the most recognizable type of maple leaf with their five lobes (sections of the leaf), smooth sides, and “U” shaped sinuses (the space between the lobes). Red maple tree leaves also have five lobes but with “V” shaped sinuses and ridged sides. Silver maple leaves are similar to a red maple with longer, narrower lobes. Leaf shape is the easiest way to identify a tree but other features can be used as well. Maple trees have an opposite branching pattern, bark that is rough on the lower portion of the tree but smooth towards the top, and dual winged “helicopter” seeds.

Preparation

Preparation for the “first run” of sap begins in late January to early February, with spiles, buckets, sap lines, and evaporators being cleaned and maple syrup makers closely watching the weather reports for the perfect sap run conditions: below freezing over night with at least a twenty degree temperature increase to above freezing during the day. When favorable conditions appear in the extended forecast, it’s time to tap the maple trees. Tapping a maple tree requires slowly drilling a 1 – 2 inch deep hole into the sapwood layer of the tree. After any wood shavings are cleared from the hole, a metal or plastic spile is gently tapped into the hole using a hammer. Most maple producers can tell when the spile is at the correct depth by a change in the pitch of the hammer hitting the spile from a high pitched “ting” to a lower pitched “thunk”. After the spile is in the tree, a bucket can be hung or a tube attached to collect the sap.

Turning sap into syrup is as simple as removing water. However, since maple sap is 97 – 99% water, at least 40 gallons of sap must be collected to produce 1 gallon of maple syrup. Most large scale producers must collect hundreds of gallons of sap before beginning the evaporation process. After enough sap has been collected, it is poured into an evaporator, a multi-chambered pan on top of a large fire box. The sap is heated and maintained at boiling for several hours, allowing the water in the sap to turn to steam and evaporate out a chimney into the air. As the water evaporates, the sugar content and density of the sap increases, with fresh sap flowing into the back of the evaporator and pushing the denser liquid into the third section of the evaporator pan. When the liquid in the third chamber reaches 66% sugar content, it is officially maple syrup! Producers can then slowly begin to pour off the syrup for packaging, keeping an eye on the sugar content and temperature of the syrup.