Students enjoy sweet lesson in creating maple syrup

Mill Road students this week are getting a sweet treat with a side of environmental instruction.

Doug Keto is teaching his Garden students how maple syrup is made by creating it at the school, from tapping trees to cooking it down and, ultimately, tasting it on pancakes made fresh on an electric griddle.

It’s a lesson Keto revived in 2023 and has been building each year he’s been with the district. While the unit teaches students how trees work and the differences between processed and homegrown foods, it doubles as a fundraiser with proceeds going directly back into the Garden program.

On Tuesday, Keto took several classes outside to see the trees he tapped lining Mill Road’s 3-5 side, teaching them how to identify that the trees are sugar maples by their bark and branches. He tapped 11 trees in all, including some on the PK-2 side of the building and by the garden.

The sap is collected through tubes threaded into closed five-gallon, food-safe buckets, and then moved into a 65-gallon drum before it is cooked down. So far, the trees have produced about 12 gallons of sap every 24 hours. He noted he was not able to tap the trees until late February, timing dictated by the conditions.

“You want below-freezing temperatures at night, above-freezing during the day,” Keto said, noting 25 degrees during the night and 40 during the day is ideal. “The freeze-thaw cycle pumps the sap through the tree.”

This year, Keto is cooking the sap down in front of the school using a propane heating station, which has given off a smell similar to marshmallows and allows the students, for the first time, to see the different stages of the process. When the sap comes out of the tree, it’s roughly 97% water with a clear appearance.

"That's a little more helpful. It will give them a better understanding of the process," he said, motioning to the clear liquid. "If someone told you this turned into syrup, they wouldn't believe you."

He explained, it takes roughly 50 gallons of sap to create one gallon of syrup. Last year roughly 170 gallons yielded four gallons of syrup. Most of it was given out in classes, though 50 eight-ounce jars were sold as a fundraiser. He plans to do the same this year.

Keto gave each student the chance to taste sap cooked down around 50% before heading back inside. After asking students to guess how the clear sap transforms to brown syrup, he explained it’s a common transformation when sugar is heated.

“When you add heat to sugar, what you do is caramelize it,” he said. “You see it when you cook onions, you cook bread, when you cook syrup, it’s just the sugar browning.”

Student questions included:

“Can a tree regenerate its sap?” (“Yes, because it just uses the water that’s available in the ground, the water it has stored and all the sugar it stored last year while it was growing, so it has everything it needs to make more sap,” Keto said.)

And, “Could you just taste sap if you see it coming down from a tree? (“Very soon, this sap will turn very bitter because the tree will start pumping chemicals through its body to tell it to start growing buds, and then flowers, and then leaves … if you try eating sap any other time of the year, other than early spring, it’s probably going to taste really nasty,” Keto said.)

Lucky for the students, the sap-turned-syrup was plenty sweet on Tuesday. Keto made each student a pancake on an electric griddle in his classroom and gave them the option of topping it with his school-made syrup or a store brand which, he pointed out to them, does not actually contain maple syrup.

Most students opted for the real stuff. And, most asked for seconds.