Mild winter brings early maple syrup tapping

R. R. Branstrom | Daily Press In the sugar shack of the Forestry Innovation Center, as nearly-finished syrup pours from the continuous flow evaporator, Tyler Tankersley stirs the liquid in the drawoff tank. From the insulated tank, it will be pumped through a filter before going into a heat-sealed drum.
R. R. Branstrom | Daily Press Maple trees in Hyde are connected to lines that draw out sap.

HYDE — Due to abnormal weather, producers of maple syrup in the Upper Peninsula began tapping trees far earlier than usual this year. It has been going well so far, but as extraction is still underway, sugarmakers were quick to point out that they won’t be able to speak on how the yielded quantity compares to other seasons for at least a few weeks.

One local research center situated in prime maple country is using high-tech equipment to not only make syrup but also study every aspect of its production. In Hyde, the Michigan State University Forestry Innovation Center is one of a number of AgBio Research Centers throughout the state, but the only one with this particular focus.

“Most of our research funding here is through the USDA,” said Director Jesse Randall, speaking over the hum of machines in the sugar house on Wednesday as bubbling sap boiled down in a massive evaporator. “We have about five or six active projects right now. And so, really, the maple syrup is the byproduct of all of the research that we do. So this is the sweet end, but this will feed into more projects.”

The trees known as sugar maples or rock maples are native to North America, so it’s rare to find maple syrup outside of the U.S. and Canada, where the climate and soil allows the trees to thrive and humans to harvest. Black, red and silver maples — all of the Acer genus, as is the sugar maple — are also used for syrup production.

The average maple tree produces sap with a sugar content of about two percent. Harvesting is done from mature trees — as a rule of thumb, a maple should be 30 to 40 years old before it’s tapped. At a sugar bush, where maples are cultivated for syrup, the sap is boiled down and condensed.

When winter prepares to draw to a close and spring just begins to peek into the woods, conditions are ripe for sap extraction. Sugars created by photosynthesis are stored as starch stored in the roots during the fall and winter. In the spring — when trees need energy to grow new buds — enzymes convert the starch; sugar enters the vessels and rises upward. Temperature fluctuations causes pressure changes within a tree and lead to the fluid we know as sap being pushed through the trunk and branches. Boring a hole into the tree allows for a tap to capture the sap as it flows. Vacuum systems are sometimes employed to extract more sap.

One part of the research at the Forestry Innovation Center involves high vacuum systems. Instead of the old-school method of hanging a bucket or bag under a tap on a tree to catch the sap, MSU’s 2500 trees in Hyde are hooked up with miles of tubes. There’s a one-inch-diameter mainline, which Randall described as having sap running along the bottom half of the tube and and a vacuum at the top. Another system — a Canadian method — uses two lines, one for the sap and one for the vacuum.

“That (two-line) one yesterday produced almost 35 percent more sap,” Randall reported. “It’s much more efficient at getting the trees to give up the sap.”

Some concern exists around whether vacuuming causes long-term harm to maple trees, but there does not appear to be evidence that it’s detrimental when done with care.

A television screen in the sugar house displays readings taken from the lines. The technology is also connected to a smartphone app.

“Every one of the main lines, I can tell what the vacuum is doing in each of those and what the temperatures are,” Randall explained, scrolling through pressure readings measured in inches of mercury. In certain conditions, lowering pressure (controlled by decreasing the vacuum) can prevent freezing.

“We have one of the smartest sugarbushes in the world,” said Randall. “It’s a mesh network out there, and so they all talk to each other.”

Pure sap brought straight from the lines to the sugar house in tanks is first reduced in a reverse osmosis (R.O.) machine, which removes a lot of the water from the solution — it can bring the sugar content from two percent  to about 15 percent. The permeate — the clean water extracted from the sap — is saved and used for washing, Randall said.

A benefit of using the R.O. machine is that it can shave about 90 percent of time off the boiling process. The R.O. machine can run without being monitored by a person; the evaporator can not.

From there, said Randall, the concentrate is run through a UV light, which sterilizes everything. “Because you have to think, when the R.O. is concentrating, we concentrate the bacteria that’s in it, the yeast … sap is just two percent sugar, so exposed to sunlight and warmer temperatures, the later you go into the season, the more the microbial load gets larger and larger.”

The microbes, though, actually do add more flavor and color that many find desirable. Following boiling, they’re safe to consume.

After being concentrated by R.O. and sterilized by light, the concentrate finally moves to the evaporator.

“We boil it because we still need the interaction of the heat with the sugar to create the color and the flavor,” Randall said.

The Forestry Innovation Center partners with other research groups around the Midwest to not only hone the science of maple syrup manufacturing and optimize production efficiency but also educate more producers around quality control.

“Around ten percent of the global supply has some level of off flavor,” said Randall. “We’re trying to get that number down.” He explained that such ill effects can develop if sap or concentrate sits in a tank too long and begins to ferment before being boiled. And if the end result is below 66.5 percent sugar, it isn’t technically syrup and can spoil.

Safety, including multiple methods of sterilization, is a priority.

An area of the woods marked with different colored flags in the woods is designated as a trial for sanitation. Randall explained that they run products through the lines to clean them:

“We’re working with five different commercially available sanitizers, only two of which are approved by FDA. And so the work that we do is getting more of these sanitizers approved.”

The entire facility — which until 2020 was called the Forest Biomass Innovation Center — is heated by a prototype woodchip burner that Randall said is one of only two in the world.

The Forestry Innovation Center is hosting a “Maple Weekend” event April 6 and 7. They will provide tours of the facility at 6005 J Rd., discuss their work, and demonstrate how some confections equipment can help producers in Michigan turn their syrup into more valuable products.


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