Maple syrup production is centered in northeastern North America, and is commonly associated with Quebec in Canada and Vermont in the U.S. However, given the correct weather conditions, it can be made wherever maple trees grow. Usually, the maple species used are the sugar maple (Acer saccharum) and the black maple (Acer nigrum), because of a high sugar content in the sap of roughly two percent. A maple syrup production farm is called a "sugar bush" or "the sugarwoods". Sap is often boiled in a "sugar house" (also known as a "sugar shack" or cabane à sucre), a building which is louvered at the top to vent the steam from the boiling sap.
Canada makes more than 80 percent of the world's maple syrup, producing about 7 million US gallons (26,000 m3) in 2005. The vast majority of this comes from Quebec: the province is by far the world's largest producer, with about 75 percent of the world production (6.515 million US gallons/24,660 cubic meters in 2005).[2] The provinces of Ontario, Nova Scotia, New Brunswick and Prince Edward Island produce smaller amounts.
Vermont is the biggest U.S. producer, with 450 thousand US gallons (1,700 m3) in 2007, followed by Maine with 225 thousand US gallons (850 m3) and New York with 224 thousand US gallons (850 m3). Wisconsin, Ohio, New Hampshire, Michigan, Pennsylvania, Massachusetts, and Connecticut all produced marketable quantities of maple syrup of less than 100 thousand US gallons (380 m3) each in 2007.[3]
Traditional tap
Two taps in a maple tree, using plastic tubing for sap collection.
Traditionally, maple syrup was harvested by tapping a maple tree through the bark and into the wood phloem, then letting the sap run into a bucket, which required daily collecting; less labour-intensive methods such as the use of continuous plastic pipelines have since superseded this, in all but cottage-scale production.
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 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. Maple sap is collected from the buckets and taken to the sugar house; if plastic tubing and pipelines are used, then the pipelines are arranged so that the sap will flow by gravity into the sugar house, or if that is not possible, into holding tanks from which the sap is pumped or transported by tanker truck to the sugar house.
A small scale evaporation pan used in Ohio.
A sugar house where sap is boiled down to maple syrup.
It takes approximately 40 liters (10 gal) of sap to be boiled down to 1 liter (1 quart) of syrup. A mature sugar maple produces about 40 liters of sap during the 4-6 week sugaring season. Trees are not tapped until they have a diameter of 25 cm (10 in) at chest-height and the tree is at least 40 years old. If the tree is more than 45 cm it can be tapped twice on opposite sides. It is recommended that the drilled tap hole have a width of 8 mm (⅓ in) and a depth of 25 to 40 mm (1.0 to 1.6 in). During cooking, the sap is fed automatically by pipe from a storage tank to a long and narrow ridged pan called the evaporator. The evaporator is usually divided into two sections, the front pan and the back pan. As the sap boils, the water evaporates; it becomes denser and sweeter. As the density of the sap increases, it works its way from the rear of the back evaporator pan to the front evaporator pan. The syrup is boiled until it reaches the correct density of maple syrup, 1333 kg/m3. The proper density of at least 66% sugar is reached when the boiling sap reached a temperature of 7 degrees F. above the boiling point of water. The density is tested with a hydrometer. If the density is too low the syrup will not be sweet enough and the syrup will spoil. If the density is too high the syrup will crystallize in bottles. When the syrup has reached the proper density, it is drawn off, filtered and bottled while hot.
Starting in the 1970s, some maple syrup producers started using reverse osmosis to remove water from sap before being further boiled down to syrup. The use of reverse osmosis allows approximately 75 to 80% of the water to be removed from the sap prior to boiling, reducing energy consumption and exposure of the syrup to high temperatures. Microbial contamination and degradation of the membranes has to be monitored.
Maple syrup is sometimes boiled down further to make maple sugar, a hard candy usually sold in pressed blocks, and maple taffy. 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 (creamy, with a consistency slightly less thick than peanut butter).
Starting in the mid 80's, northern communities in the province of Quebec began to open the "Cabane à Sucre" or Sugar Shacks to the public. These sugar shacks were generally located on large maple farms and often were built solely for tourist purposes. These sugar shacks serve maple syrup direct to the public and also are often restaurants serving maple syrup inspired meals and treats.
