Maple syrup

Bottled maple syrup produced in Quebec.

A sugar shack, where sap is boiled down to maple syrup.

Maple syrup is a sweet syrup (thick, sticky solution of sugar and water) made by concentrating the sap of maple trees. It particcular maple syrup comes from the sap of the sugar maple or hard maple (Acer saccharum), but the black maple (Acer nigrum) and a few other maples can produce maple syrup.

Maple syrup is one of the oldest North American crops and one of the few uniquely North American (Saupe 2007; Willits 1958). The northeastern and northcentral region of North America is the only region in the world where one can find both the sugar maple and the correct environmental conditions to yield the sap to produce maple syrup (Schlager 1994). Minnesota in the United States is the western edge for sugar maple trees (Saupe 2007).

Maple syrup is a common sweetener used with pancakes, waffles, and french toast. It is sometimes used as an ingredient in baking or in preparing desserts.

Sap

Sap is the fluid carried inside the xylem or phloem of a plant, circulating to distribute food and water to various parts of the plant.

Although in vascular plants, the xylem is the principal water transporting medium and the phloem the main pathway of sugar transport, at times sugars do move in the xylem, and it is the xylem that is the source of the sugar to produce maple syrup. In late winter/early spring, producers of maple syrup tap trees and collect a sugary solution from the xylem, derived from carbohydrates stored in the stem. This is then concentrated to make maple syrup.

At the time of harvest, the sap of maple trees contains sucrose and trace amounts of other sugars and oligosaccharides, calcium, potassium, phosphorus, iron, B vitamins, organic acids, amino acids, and about 90 percent water (Schlager 1994; Saupe 2007). The typically concentration of sucrose is about 2 to 3 percent, but can range from 0.5% to 10% (Saupe 2007; Kozlowski and Pallardy 1997).

Sap flows in the early spring, usually February through April, and requires cold nights (freezing) followed by warm days. The flow of the sap in the xylem is not related to evaporation from leaf surfaces, because the leaves are not yet out, and it is not related to root pressure (Saupe 2007; Johnson et al. 1987). The flow of sap in the dormant trees is related to positive pressures in the stem, with maximum yields when the wood temperature fluctuates above and below 0 degrees centigrade (Johnson et al. 1987). It appears related to gases in the xylem dissolving as the temperature cools and pressure decreases; water being drawn from adjacent cells; ice crystals forming in the xylem cells and intercellular spaces during the freeze cycle, locking the gases in the ice; and then with the thaw cycle the ice melting and the compressed gases expanding and creating pressure (Saupe 2007; Johnson et al. 1987; Tyree 2001). For this process to happen, sucrose in the sap is required (Johnson et al. 1987). Carbon dioxide may be the main gas involved in creating the pressure, and both sucrose and lviing cells may be required for the cellular respiration that yields this gas (Saupe 2007).

It appears that only a few trees meet the proper conditions for this phenomena, with the sugar maple (Acer saccharum) the preferred tree, the closely related black maple (Acer nigrum) having a lesser yield, and the red maple (Acer rubrum) and silver maple (Acer saccharinum) being used less often (Schlager 1994), with the red maple producing a less sugary, and stronger tasting maple syrup.

Production

The production of maple syrup was shown to French and British settlers by Native American tribes, such as the Algonquins. Canada produces more than 80 percent of the world's maple syrup, producing about 7 million gallons in 2003 and in 2004, with over 90% coming from Quebec (NASS 2005). (Figures are in US gallsons. The Canadian imperial gallon times 1.20218 equals one U.S. gallon.) The Canadian province of Quebec is by far the world's largest producer, with about 75 percent of the world production. The provinces of Ontario, Nova Scotia, and New Brunswick produce smaller amounts. Vermont is the biggest U.S. producer, with 410,000 gallons in 2005, followed by Maine (265,000), New York (222,000), and then a half-dozen other states with smaller industries (Ohio, Pennsylvania, Michigan, New Hampshire, Wisconsin, Massachusetts, and Connecticut).

Production is concentrated in February, March, and April, depending on local weather conditions. 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.

A maple syrup production farm may be called a sugarbush or the sugarwoods. Sap is boiled in a "sugar house" or "sap 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 maple sap.

Maple syrup Nutritional value per 100 g
Energy 260 kcal   1090 kJ
Carbohydrates     67.09 g - Sugars  59.52 g - Dietary fiber  0 g   Fat 0.20 g Protein 0 g Thiamin (Vit. B1)  0.006 mg   0% Riboflavin (Vit. B2)  0.01 mg   1% Niacin (Vit. B3)  0.03 mg   0% Pantothenic acid (B5)  0.036 mg  1% Vitamin B6  0.002 mg 0% Folate (Vit. B9)  0 μg  0% Vitamin C  0 mg 0% Calcium  67 mg 7% Iron  1.20 mg 10% Magnesium  14 mg 4%  Phosphorus  2 mg 0% Potassium  204 mg   4% Zinc  4.16 mg 42%
Percentages are relative to US recommendations for adults. Source: USDA Nutrient database

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; more advanced methods have since superseded this.

File:Making Maple Syrup.JPG

A small scale evaporation pan used in Ohio

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. Most contemporary producers use a 5/16" or 19/64" outside diameter drill bit to drill with. A tap hole depth of 1" to 1 1/2" is a common recommended depth.

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 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 (creamy, with a consistency slightly less thick than peanut butter).

Chemistry

Maple syrup contains about 67% solids of which about 89% is sucrose; the remainder is primarily fructose and glucose, with traces of other sugars. Maple syrup is produced by heat, or increasingly with reverse osmosis to remove about 90 % of the water, with no added ingredients, and must reach 66 °Bx (degrees brix) in order to legally be "pure maple syrup". It possesses some nutritional value, containing calcium (greater than milk, by volume), potassium (more than bananas, by weight), manganese, magnesium, phosphorous, iron, thiamin. It also contains traces of vitamins B2, B5, B6, riboflavin, biotin and folic acid, and many amino acids and phenolic compounds. A serving that includes 50 ml of maple syrup contains the following recommended daily allowances: Calcium 6%, Iron 5%, Manganese 2%, Thiamin 6%, Riboflavin 2%. Its caloric value is around 40 per tablespoon (15 ml), compared with 64 for honey and 60 for corn syrup.

Grades

U.S., Vermont, and Canadian grading

U.S. Syrup grades. Left to right, Vermont Fancy, Grade A Medium Amber, Grade A Dark Amber, Grade B

Grading standards are the same for most of the United States. Maple syrup is divided into two major grades, Grade A and Grade B. Grade A is further broken down into three subgrades: Grade A Light Amber (sometimes known as "Fancy"), Grade A Medium Amber, and Grade A Dark Amber. Grade B is darker than Grade A Dark Amber. The Vermont Agency of Agriculture Food and Markets uses a similar grading system of color and taste. The grade "Vermont Fancy" is similar in color and taste to U.S Grade A Light (Fancy). The Vermont grading system differs from the U.S. in maintaining a very slightly higher standard of product density. Vermont maple is boiled just a bit longer for a slightly thicker product. The ratio of number of gallons of sap to gallon of finished syrup is higher in Vermont. Maple syrup is sold by liquid volume, not weight, however a gallon of Vermont Grade A Medium Amber weighs slightly more than a gallon of U.S. Grade A Medium Amber. The Vermont graded product has one-half percent more solids and less water in its composition.

In Canada, there are three grades containing several color classes, ranging from Canada #1, including Extra Light (sometimes known as AA), Light (A), and Medium (B); through #2, Amber (C); and finally #3 Dark (D). A typical year's yield will include about 25-30% of each of the #1 colors, 10% Amber, and 2% Dark. Extra light syrups are recommended for making maple sugar candy, on pancakes and waffles; Light for French toast, desserts and cereals; Medium for glazing, sweetening, or eating on its own. Number 2 grade syrups are intended for baking and flavouring. In addition, Canada #2 Amber may be labeled Ontario Amber for farm sales in that province only. Number 3 grade syrup is heavy, and restricted for use in commercial flavourings.

A non-table grade of syrup called "commercial," or Grade C is also produced. This is very dark, with a very strong flavour. Commercial maple syrup is generally used as a flavouring agent in other products.

The grades roughly correspond to what point in the season the syrup was made. U.S. Grade A Light Amber and Canada #1 Extra Light is early season syrup, while U.S. Grade B/Canada #2 and #3 is late season syrup. Typically Grade A (especially Grade A Light Amber) and #1 Extra Light has a milder, more delicate flavor than Grade B or #3, which is very dark with a robust flavor. The dark grades of syrup are primarily used for cooking and baking.

Off-flavours

Sometimes off-flavours are found in maple syrup. While this is more common toward the end of the season in the production of commercial grade product, it may also be present early in the season during the production of U.S. Grade A Light or Canada #1 grade. Identification of off-flavour in table grades is cause for ceasing production and either dumping the product or reclassifying the product as commercial grade if the off-flavour is slight. Off-flavours are described as: metabolism, derived from metabolic changes in the tree as spring arrives and having either a woody, popcorn, or sometimes peanutbutter-like flavour; buddy, referring to the swelling of the new buds and it impact on the flavour and having a bitter chocolate or burnt flavour; and ferment, an off-taste caused by fermentation and having a honey or fruity flavour, often accompanied by surface foam. Additionally, if trees are stressed or fighting off disease or insects (eg. gypsy moths), they will produce a folic-like acid causing a bad taste. After an ice storm, trees may also produce the same acid.

Use in food and cultural significance

Two taps in a maple tree, using plastic tubing for sap collection.

Maple syrup and its artificial imitations are the preferred toppings for crêpes, pancakes, waffles, and French toast in North America. Maple syrup can also be used for a variety of uses, including: biscuits, fresh donuts, fried dough, fritters, ice cream, hot cereal, and fresh fruit (especially grapefruit). It is also used as sweetener for applesauce, baked beans, candied sweet potatoes, winter squash, cakes, pies, breads, fudge and other candy, milkshakes, tea, coffee, and hot toddys.

Maple syrup and maple sugar were used during the American Civil War and by abolitionists in the years prior to the war, because most cane sugar and molasses was produced by Southern slaves.

In New England, Quebec and eastern Ontario, the process has become part of the culture. One tradition is going to sugar houses (cabanes à sucre) in early spring for meals are served with maple syrup-based products, especially the dish known variously as maple taffee (in English Canada), Tire sur la neige (in Quebec), and sugar on snow (in the United States). This is thickened hot syrup poured onto fresh snow and then eaten off sticks as it quickly cools. This thick maple syrup-based candy is served with yeast-risen doughnuts, sour dill pickles, and coffee. Owing to the sugar maple tree's predominance in southeastern Canada (where European settlement of what would become Canada began), its leaf has come to symbolize the country, and is depicted on its flag. Several U.S. states, including New York and Vermont, have the sugar maple as their state tree. A scene of sap collection is depicted on the Vermont state quarter.

Imitation maple syrup

Many "maple-flavored syrup" are imitations (table syrups), which are less expensive than real maple syrup. Often sold in the United States, the primary ingredient is most often dark corn syrup flavored with sotolon, with little (2-3 percent) or no real maple syrup content. They are usually thickened far beyond the viscosity of real maple syrup. Since U.S. labeling laws prohibit these products from being labelled "maple syrup," many manufacturers simply call the imitation "syrup" or "pancake syrup." Québécois sometimes refer to imitation maple syrup as sirop de poteau ("pole syrup"), a joke referring to the syrup as having been made by tapping telephone poles.

References

ISBN links support NWE through referral fees

• National Agricultural Statistics Service (NASS), United States Department of Agriculture. 2005. 2005 New England maple syrup survey. New England Agricultrual Statistics. Retrieved May 4, 2007.

See also

• Birch syrup
• Sap (plant)

External links

Wikibooks Cookbook has more about this subject:

Maple syrup

• The North American Maple Syrup Council – includes extensive links to state and local maple syrup producers associations and other maple-related links.
• "North American Maple Syrup Producers Manual" (1st edition), edited by Melvin R. Koelling and Randall B. Heiligmann, Ohio State University Extension (Bulletin 856), 1996. (archived at Wayback Machine) – "The Bible" of maple syrup production. (Note that as of 2007, there is a second edition only available as a hard copy.)
• "Maple Syrup Quality Control Manual" by Kathryn Hopkins, University of Maine Cooperative Extension (Bulletin 7038)
• Vermont Maple Sugar Makers' Association & Vermont Maple Foundation
• Cornell Sugar Maple Research & Extension Program
• University of Vermont Proctor Maple Research Center
• The Canadian Encyclopedia: Maple Sugar Industry
• "Pure Pennsylvania Maple Syrup": A Photo Essay by Peter J. Singhofen, 2005.
• "A Sugarbush Tale": Short documentary about small-scale maple-syrup production in Vermont
• Cooking For Engineers - Kitchen Notes: Maple Syrup Grades
• "Fresh From Vermont’s Maples, a Taste of Terroir" by Jane Black, New York Times, December 20, 2006.
• National Agricultural Statistics Service: Specialty Crops - Production data for U.S. agricultural commodities, including maple syrup. (Highlight "Maple Syrup" and click "Search".)

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