Maple Syrup Production


There are many legends concerning the discovery of making maple syrup- most of which are probably more speculation than truth. One story states that a Native American stuck his tomahawk in a tree and the sap dripped into a container sitting under the tree. When the sap, which appeared to be water, was later used for cooking, the sap was reduced to syrup imparting a sweet and distinctive flavor to the food. From this event, maple syrup became an important ingredient in cooking. It was given the name sinzibukwud.

While there are many such stories told, we do know that early settlers produced and used maple syrup as a basic sweetener. In early times, gashes were cut in the maple trees to allow the sap to flow, but it was soon discovered that drilling a hole in the tree resulted in good sap flow and less damage to the tree. Sap was probably collected in wooden or clay trough-like containers in very early processes, but wooden buckets or “keelers” soon replaced these. A wooden spout, or “spile” was placed in the hole in the tree to allow the sap to drip into the bucket. 

Although equipment has been modernized, the basic process of producing maple syrup remains the same. Today, trees are tapped when they reach a diameter of 11 or 12 inches. A 5/16” diameter hole is drilled 1 ½ to 2” deep in the tree each year. Sugar makers may use metal spouts and buckets to collect the sap or it may be gathered through a network of plastic tubing connecting the trees to a central collecting tank.

The sap is available only during the dormant stage of the tree and will flow only when the temperature is above freezing. In the early spring, nature causes the sap to flow within the tree as warmer temperatures remove the frost from the tree itself and the ground surrounding the tree. Thus it is practical to tap the trees in early spring with the approach of warmer weather. As the temperatures rise and the frost leaves the ground, the sap flows less freely and eventually stops and will not flow again until colder weather freezes the ground and sets the stage for another thaw. Thus varying weather conditions and rapid changes from sub-freezing temperatures causes sap flow and contributes to a good maple season. This is the basis for the common belief that cold nights and warm days are necessary for the production of maple syrup. In Pennsylvania, the average date for the opening of the season is the latter part of February and the closing date is early April, although this changes with unusual weather conditions.

There are over 100 varieties of maple trees, but the sugar maple has a high concentration of sugar. The sap from the tree is colorless liquid. When the sap has been collected, it is brought to the sugar house where there are usually several large storage tanks. Here the actual processing is done. It takes approximately fifty gallons of sap to produce one gallon of syrup. Many of today’s maple producers utilize a reverse osmosis machine, which separates the water from the sugar, leaving a concentrated sap. The concentrated sap then moves to the evaporator, a large wood or oil fired pan where the remaining water is evaporated by boiling. The evaporator is usually a two-part arrangement. Today’s modern evaporators have a series of flues in the bottom which trap heat and also give additional boiling area over the earlier flat-bottomed evaporator. Most evaporators are covered by hoods, which carry the steam from the boiling out through vents in the roof. A great white plume of steam rising from the sugar house is a familiar sight in spring.

As the sap becomes more concentrated, it flows through a connecting pipe into the front pan of evaporator-the syrup pan. This flat-bottomed pan is arranged with a series of baffles, which directs the flow of the sap so that the sap is most concentrated in the section of the pan closest to the draw-off valve. This controlled flow pattern prevents the more dense sap from intermixing with the less concentrated and results in a better product.

Sap becomes syrup at approximately 7 degrees above the boiling point of water. Since this changes with elevation and barometric pressure, the temperature at which sap becomes syrup also changes. Most syrup producers check the density of their product using a hydrometer. Because of the volume of syrup and the amount of heat involved in the large evaporator, many producers draw syrup off the evaporator and transfer it to a finishing pan where it is easier to control the density. Finishing is usually done in a small flat-bottomed pan with a controllable heat source. The finished syrup is then filtered to remove any impurities, graded, and packaged either in drums for later use or in containers for immediate sales.