The W.K. Kellogg Experimental Forest’s annual Maple Syrup Open House will take place this Saturday, March 10 from 12 p.m. to 5 p.m. For a price of $1 per person, Open House attendees can learn and witness firsthand how syrup is made.
Visitors have the option of sampling fresh syrup in the Maple Manor (a small log cabin where syrup is made), taking a wagon ride tour of the sugar bush and participating in family activities like face painting and a sap bucket toss. Syrup and other maple products will also be available for purchase.
According to Kellogg Forest manager and forester Kenneth Kettler, the Maple Syrup Festival is the biggest outreach event the forest has organized consistently since 1985. Kettler also said that attendance varies with the weather, but there have been as many as a thousand visitors to the forest for the Maple Syrup Open House when conditions are favorable.
“It’s a fun way to get the public out [to the forest] and kind of show them what’s going on here and get them looking at different kinds of activities we have,” he said. “A lot of people don’t even know this place is here.”
Kellogg Forest, which is about 760 acres, is available to the public for recreational use, and to researchers for their own personal projects. Kettler said researchers are currently investigating the value loss on the quality of timber that results from tapping trees.
“There’s different ways that you can set up the sap collection,” Kettler said. “Some of them are just buckets, some are gravity fed lines, and they have these newer systems that are vacuum, and those all have a different impact on what kind of defect is created in the wood.”
Visitors to Kellogg on March 10 will be able to witness the sap collection process for themselves. Kellogg Forest has two main “sugar bushes” or groves of sugar maples–a north and a south–that use gravity-fed systems to collect sap that is eventually turned into syrup.
Tapped trees should be at least 10 inches in diameter at chest height, or about four and a half feet above the ground. For every extra five inches in diameter, the tree can be tapped an extra time.
“You don’t want to go and tap them around the same height because that would girdle the tree and cut off its food supply, so you want to tap them in a spiral,” Kettler said.
Sap is only drawn from trees during part of the year–primarily during the month of March–but sap production is a year-round process. When trees go dormant in the fall and throughout the winter, the carbohydrates the trees produce through photosynthesis during the warmer months are stored within the trees. Once temperatures start to warm up (to about 40 degrees during the day and 20 degrees at night) enzymes in the trees turn the carbohydrates into sugar. A pressure difference is also created that causes the sap to be pushed out where they’re tapped. The sap then flows down to large collection tanks through narrow tubing.
While syrup can technically be made from any kind of trees, Kettler said sugar maples are typically used due to the high sugar content (around 2 percent) in their sap. According to Kettler the higher the sugar content is in a tree, the less sap it takes to make syrup. For typical sugar maples, it would take 43 gallons of sap to make one gallon of maple syrup.
“They call it the 86 rule–if you take 86 and divide it by whatever the sugar content is of the sap, that’ll tell you how many gallons of sap it will take to make one gallon of syrup,” he said.
The sugar content of a tree depends both on its type and the year and the location where it was planted. For example Kettler said trees that have more room to grow like ones bordering the road, on the edge of the forest have more leaves to perform photosynthesis and store carbohydrates in the tree.
Kettler said the weather impacts the success of the maple syrup season. If the weather gets too cold or too warm, the sap doesn’t flow from the trees. Once the trees start to bud, the sap can no longer be used due to its bitter taste. Usually the sap season lasts until the end of March.
After the sap is collected, it’s brought to a big, steel tank outside Maple Manor. The sap is filtered several times and pumped into the manor itself, where it heats up in a series of pans. When it’s heated, the water evaporates from the sap, and the sugar concentration rises until it becomes syrup. When syrup is being made, a volunteer sits in the cabin, testing its sugar content and temperature.
“It has to be 66 percent sugar to be considered maple syrup,” Kettler said. “And also they use the temperature; it has to be 219 degrees.”
Syrup is then transferred into the canner where it is filtered again and poured into jugs.
The syrup-making process is maintained almost entirely by volunteers.
“The volunteers do pretty much everything. We just provide oversight for them and support when they need it,” Kettler said. “They do all the tapping, all the cleanup at the end of the year, they collect the sap and sit in the house, and they boil it, so they put in a ton of hours.”
Potential Kellogg Forest volunteers can visit the Kellogg Biological Station’s website for more information.
“They have a few different documents you’ll fill out, and I think you’ll have like an interview to see what you’re interested in because there’s a lot of opportunities,” he said. “So you go through that process, and then we have a training usually in the spring.”