What causes the sap to flow? Temperature change.
It all starts with a sugar bush. While that sounds like something out of the board game Candy Land, it's actually another name for a stand of sugar maples -- one of the trees that gives us maple syrup.
"We're standing here at the bottom end of the sugar bush," said Thomas Worthley, an associate professor at UConn, as we gaze out at a wide stand of about 150 sugar maples near the main campus.
They're tall, healthy trees with wide crowns that are being harvested for maple syrup. But this isn't your old-school maple syrup tap. What you won't find here are hundreds of silver buckets hanging off trees. Instead, there's an interconnected web of rubber tubing that runs tap-to-tap, from tree to tree.
It's a high-tech "sap run," which helps producers more efficiently collect hundreds of gallons of sap from the trees. "Everything's on a gravity system, so it's all flowing a little bit, or sometimes a lot, in a downhill direction" into an enormous collection bin, said Jennifer Kilburn, a senior at the school, who helped to set it all up.
But what causes the sap to flow? Worthley said it's temperature change.
Warm days start the movement of sugars out of storage and into the tree, but "when it cools off at night, the opposite happens," Worthley said. "All that sugar material goes back into storage, the tree loses the moisture, and when it warms up the next day it takes it all up again," he continued. "So it's this change in temperature of warm days and cool nights that really causes the sap to flow in a significant way."
Worthley said the recent cold spell has delayed this year's syrup season.
Mark Harran, a maple syrup and hay farmer in Litchfield, said he agrees. His yields have been pretty good so far, but he said they came late and haven't been continuous. Harran said he's hopeful the below-average temperature predictions extending into mid-April will save the season.
"We could catch up and have what I would consider a reasonably good season. Not an outstanding one by any means, but similar to last year," Harran said. "Last year, we didn't have any sap until around March ten or eleventh, and then in the last two weeks, the trees were gushing sap, and we ended up with a reasonable year," he said. "It's always great if it starts the first of February and runs continuously through the season. That's when we have absolutely fantastic years, but that will not be the case this year."
Harran said sap typically runs about six to eight weeks and slows down when the trees begin to bud: when there's warm days and warm nights. "Think about it: usually by April first, at least the crocuses are sprouted up and the daffodils are beginning to grow," Harran said. "Right now, my daffodil beds have about two feet of snow on them. So everything's behind this year."
Back at UConn, Jennifer Kilburn and Thomas Worthley transport sap they've gathered from the sugar bush into a pickup truck and drive a few miles up the road to the school's sugar shack. There, it's poured into a huge wood-fired evaporator, which boils it down to syrup.
Kilburn said about 40 gallons of sap boil down to one gallon of syrup. She said temperature is a key part of this process, too. Sugar maple sap needs to be boiled at 219 degrees Fahrenheit, seven ticks above the boiling point of water. Otherwise, it gets too thick.
"When we're down here boiling, we'll actually put a sign out on the end of the road just saying that we're down here and we're open, and people will sometimes just walk in, check it out, and buy some syrup," Kilburn said.
School officials said any syrup that doesn't get sold will find another home, purchased by dining services to be enjoyed by both students and important dignitaries visiting the campus.
