Maple syrup is a sweetener made from the sap of maple trees (Acer saccharum). Production is concentrated in February, March and April, depending on local weather conditions. Freezing nights and warm days are needed in order to induce sap flows. The change in temperature from above to below freezing causes water uptake from the soil, and temperatures above freezing cause a stem pressure to develop, which along with gravity, causes sap to flow out of tapholes or other wounds in the stem or branches. To collect the sap, holes are bored into the maple trees and hollow tubes (taps, spouts, spiles) are inserted. Sap flows through the spouts into buckets or into plastic tubing. Modern use of plastic tubing with a partial vacuum has enabled increased production. A hole must be drilled in a new location each year, as the old hole will produce sap for only one season due to the natural healing process of the tree, called walling-off.
During processing, the sap is fed automatically from the storage tank through a valve to a flat pan to boil it down until it forms a sweet syrup. The process is slow, because most of the water has to boil out of the sap before it is the right density. It takes approximately 40 litres of sap to make one litre of maple syrup, and a mature sugar maple produces about 40 litres (10 gallons) of sap during the 4-6 week sugaring season. Trees are not tapped until they have a diameter of 25 centimetres (10 inches) at chest-height and the tree is at least 40 years old. Maple syrup is sometimes boiled down further to make maple sugar, a hard candy usually sold in pressed blocks, and maple toffee. Intermediate levels of boiling can also be used to create various intermediate products, including maple cream (less hard and granular than maple sugar) and maple butter.
Ste-Pétronille, Île d'Orléans, Québec, Canada