Maple sap does not exit the maple tree automatically. It will only flow from wounds—which are called taps. In commercial production of maple syrup, these taps are located for convenient and economical sap collection, while doing as little damage to the tree as possible. A spile is obtained through one of several commercial suppliers, and this spile is inserted into the tap for sap collection. A bucket may be hung on the spile and sap collected from the bucket as necessary; or plastic tubing may be connected to the spile and run to a central location for convenience.
Due to the short and often hectic sap season, a producer must decide what is needed and have the necessary supplies year after year so equipment must be cleaned and serviced. Often, the maple producer will even install plastic tubing during the winter months to save time during the sap season.
When the weather conditions are right, tapping begins. (You can get help to determine the right time from an experienced maple producer or maple literature). Once the trees are tapped and alternate freezing and thawing occurs, things become very busy. Maple sap does not keep well, so it must be collected once a day.
Maple producers using plastic tubing often attach vacuum pumps to the tubing. This keeps sap moving in the line and significantly increases the sap flow per tree. Large storage tanks are needed at the sap house for storage of the day's sap collection while awaiting processing. Plastic tubing is more readily accepted by maple producers because of collection convenience and increased production.
At the sugar house, maple sap must be processed to a concentrated density of 66% (maple syrup). It takes approximately 40 gallons of maple sap to make one gallon of maple syrup. This 40 to 1 ratio (average) makes the maple industry a very energy consuming business. Several years ago, oil was very convenient and widely used to concentrate the maple sap, but with the increase in oil prices, alternate fuels have been explored. Producers are often returning to the use of wood fuel for sap concentration.
There are a lot of backyard producers using the “batch system” to make maple syrup for family and friends. A pan is filled with maple sap and boiled. As the level in the pan drops, more sap is added until enough has been added to warrant finishing off the batch. The batch is evaporated to syrup, removed from the heat, and bottled or eaten. (Usually there is a continuous tasting by the operator—especially the first batch of the season). The entire batch process is then repeated, but most backyard operations finish only one batch per day.
Nearly all modern day evaporators are a continuous process. Sap is continually added at one point in the unit. The following are some methods of continuous sap concentration:
You now have finished maple syrup. Check it for the correct density with either a hydrometer or a refractometer. Maple syrup is now packaged (hot-190°F) and sealed in consumer-sized packages, and the packaged syrup is stored in a cool, dry place until needed.
There are two factors that may determine the end of a maple season and cause the maple producer to stop operations for the season. First, no more freezing weather; and second, the sugar content of maple sap slowly diminishes and drops to a point where it is not economical to process the maple sap - this happens when the trees start to bud, and the sap flow changes in composition and becomes unusable.
Now that the season has ended, the clean up task begins. All buckets and tanks are washed and stored. Evaporators, vapor compression distillers and reverse osmosis are drained, washed, and/or flushed as per manufacturer's directions. All units are drained, flushed and stored, and tubing is cleaned. Whether tubing is left up in the sugar bush or taken down is an option of the individual maple producer. When the tubing is left up in the sugar bush, a flushing solution is pumped through the entire tubing system, then drained and capped. When the tubing is taken down and brought to the sugar house, the tubing is flushed with a solution, drained and stored in a cool, dry place. Equipment and building are left in waiting for another maple season.