March 10, 2022 at 2:02 p.m.
Science on Tap looks at maple syrup in Wisconsin
Science on Tap looks at maple syrup in Wisconsin
She started with the roots of maple syrup production. She said it started with Native American tribes, which centered in Northern Wisconsin. She said the manufacturing of sugar was one of the principal industries for those people. They used birch or elm bark collection pots with notches in the tree. Hot stones would be used to boil the sap into sugar. Using this method, she said, they were able to produce large quantities of sugar, which they packed in birch bark vessels and buried in the ground. Sugar stayed in good condition for a longer period of time than maple syrup would.
In the 1600s, Baroun said, iron trade pots began to be used. As early as the 1700s, observers reported a band of 1,500 Menominee Indians made 90 tons of sugar in one season. This sugar was often used in place of seasoning and provided energy in lean times. At that time, the average person consumed 120 pounds of maple sugar per year.
Up until 1900, all maple sap was cooked all the way to solid sugar. This was true until sealed jar lids came along. Maple sugar was still important, however. Cane sugar was expensive and difficult to get, and maple sugar could be buried in the ground to keep it cool.
Today, Canada produces over 5 million pounds of maple syrup per year. In the United States, Wisconsin ranks fourth in maple syrup production, with 83,000 taps throughout the state. In 2021, Baroun said, with a yield of 0.340 gallons per tap, approximately 300,000 gallons of maple syrup were made. In 2017, she said, maple syrup generated $7.5 million in sales in the state.
Maple trees are unique in that they have a highly developed sap-flow mechanism. This makes them ideal for tapping. When looking to identify maple trees, Baroun suggested going out in the fall, before the leaves come off the trees and mark those trees in some way, such as by tying a rope around the tree to identify it later in the winter. There are four kinds of maple trees: sugar, black, red and silver. The sugar maple is the Wisconsin state tree and usually has a higher sugar concentration than the other three. However, all four types of trees can be tapped.
Baroun spoke about sap, what it is and its purpose. During the summer, trees conduct photosynthesis, creating starch. That starch is stored in the root system. Throughout the late fall and winter, that starch is then converted to sugar. That sugar helps protect the tree from the cold.
In Wisconsin, trees are tapped from the middle of February to the middle of April, she said. In the north, tapping can begin as late as the middle of March. Tapping is weather dependent. Temperatures need to be above 32 degrees during the day, but still falling below freezing at night. At night, the sap will leave the roots and travel up the tree. During the day, the sap runs back down the tree. This happens due to gravity and the pressure in the tree. Therefore, Baroun said, the lower the atmospheric pressure, the better the sap run. There are many influences on sap flow. These include the length of the freeze and thaw process, wind, atmospheric pressure, climate, snow cover or frost and the previous year's precipitation amounts. If the prior year is dry, she said, sap yield will be less the following year. She said 2012 was one of the worst maple syrup years in Wisconsin, on record, for that reason.
Baroun also spoke about the number of taps that could be put in a tree. With the tree diameter measures at chest height, a 10-inch diameter would call for one tap. A tree 20 inches in diameter would mean two taps. No more than four taps should be put in any one tree, however.
She spoke about how tapping trees was accomplished. Drill bits come in 3/16, 5/16 and 7/16, she said. These are sharper than standard drill taps. When looking for a place to tap the tree, Baroun stays at least three inches from old taps, using a star pattern. She said trees should also be tapped around the whole diameter, rather than just on the south side.
Each tap hole should produce approximately 10 gallons of sap per year. When tapping, the drill should be put at a five to 10 degree angle. If the drill is placed at a downward angle, ice will push the spout back. If the tap hole is at a higher angle, depth of the hole will be lost. Holes should be drilled 1 3/4 to 2 inches deep. The sap, Baroun said, is in the first three layers of the tree.
Using an eight-ounce hammer, Baroun hits the spout with the right strength to put the tap into the tree. She said she listens for the change in the sound of the tap and stops there. Hitting the tap too hard could split the tree. Hitting the tap too soft could result in the spout pulling out of the tree.
Collection of sap is now done in either plastic pales or sap sacks or in tubing runs. Some of the advantages of using pails or sap sacks include the fact that they are easier to pull out and to manage the woods out of season. They also add a more historic look and allow the tapper the ability to see the production of each tree separately. However, this method is more expensive per tap hole and requires more labor. Sap sacks can also be damaged by animals.
Tubing has some advantages, Baroun said. These include the requirement of less labor and being less expensive per tap. Tubing also allows producers to tap on steep terrain and to centralize a group of trees. There is also better production per tap.
Tubing does have its disadvantages, however. It requires more maintenance and can get in the way when completing out of season tasks such as cutting wood or hunting. There is no sense of nostalgia with this type of collection, Baroun said, and the installation is more difficult.
It is best to collect sap every day to ensure it stays fresh, she said. Clean, food grade containers should be used for collection. Baroun's system uses solar vacuum to powers the battery that powers the sap collection pump.
It is best to use maple sap that is two percent sugar. Trees in a lawn, she said, have less competition and usually produce higher sugar levels in their sap. When the percentage drops to one percent, it is not recommended to be used and could signify the end of the season.
When processing sap, producers should remember sap is a perishable product. Therefore, the faster the maple sap can be processed, the better syrup it will make. Sap must be stored at 38 degrees or less and should not be stored for more than 24 hours before processing.
Many maple producers use a reverse osmosis (RO) system, Baroun said. Some can reach over 18% sugar concentration, but there is concern by some that the flavor can be impacted by a short cooking time. Heat sources are varied, she said. It could be, wood, propane or fuel oil. Sap can be boiled with a propane boiler, a wood fire under a sugar pan, or with a hobby evaporator. A hydrometer in a hydrometer cup is used to show when the syrup is considered maple syrup. There is a fine line below which syrup will spoil and may be very thin and watery. If the concentration is too high, it may create sugar crystals.
Baroun also looked at different grades of maple syrup. Lighter grades, she said, tend to come from earlier in the season. They have more sucrose sugar, which will caramelize less in the cooking process. Darker grades have more glucose sugar, which does caramelize during cooking. This brings with it a stronger flavor and more caramel coloring.
Maple syrup is high in manganese, riboflavin, zinc, magnesium, calcium and potassium, she said. It is higher in minerals than corn syrup, honey, brown sugar or white sugar. According to many studies, Baroun said, maple syrup is healthier than other sweeteners because it contains over 40 antioxidants and is also lower in calories than many other sweeteners.
Maple syrup is used in a variety of speciality products as well. It can be found in mustard, BBQ sauce, cotton candy, root beer and a variety of flavored syrups, among many other products. Baroun said, according to MarketWatch, maple may soon replace pumpkin spice as the taste sensation at Starbucks. Technomic reported sales of non-alcoholic maple flavored beverages were up 85% and alcoholic maple flavored drinks are up 14%, with products such as maple infused whiskey and vodka.
Beckie Gaskill may be reached via email at [email protected].
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