It’s one of the earliest signs that spring is on its way: bags and buckets hanging from the trunks of trees, collecting a delicious harvest even before the leaves start to appear.
The maple syrup season is in full swing at Carpenter Nature Center. CNC has been making small amounts of maple syrup for about 30 years now. Because the center doesn’t produce much syrup, the process is done each year for education. Last Sunday, CNC held its first public maple syrup making session.
Maple syrup comes from maple tree sap, the liquid that carries the nutrients the tree needs to grow, explained CNC Program Director Mayme Johnson. During the summer months, trees make sugars through the process of photosynthesis. Excess sugars produced are stored with water in the root system for the winter, and in the spring, the sugars and water are drawn back up to the branches to feed new buds. Tapping a maple tree diverts a tiny amount of that sap as it’s rising up to the branches from the roots, taking it out of the tree to be collected and turned into syrup.
The syrup season fits in a narrow window each spring; Johnson said that some years the season has been less than two weeks. Maple sap can only be harvested under strict weather conditions. Temperatures have to be above freezing during the day, but below freezing at night, Johnson said.
“It builds up the pressure inside the tree,” she said, “that freezing and thawing.”
Those conditions typically happen in early March and are done by April, and also make sap collecting possible only in the northern U.S. and southern Canada.
Making maple syrup is relatively simple. First, Johnson said, a maple tree has to be identified. At CNC, syrup is made from silver maples, red maples and box elders, which are part of the maple family.
Once identified, a tree is measured; guidelines recommend that a tree be at least 12 inches in diameter before it’s tapped. Then a small hole has to be drilled and a spile hammered gently into place. The spile provides a sort of open spigot for the sap to drip out. A bucket or bag is hung on the spile to collect the dripping sap.
Once collected, the sap is boiled to evaporate the water off. That process is what takes the bulk of the time.
Maple trees are the tree of choice for making syrup because of their high sugar content. Even so, sugar levels are still low. Sugar maples, which are preferred for their high sugar, have just 2.5 to 3 percent sugar. The box elders at CNC are even lower, running at 1 to 1.5 percent. In order to make the syrup, all the water has to be boiled off.
“That is what takes the time, the boiling and boiling and boiling,” Johnson said.
Given sap with a sugar concentration of 1 percent, it would take 86 gallons of sap to make just one gallon of syrup. Johnson said that at CNC, they can boil about 10 gallons of sap a day.
Once the boiling is done, all that’s left is to filter and bottle the syrup.
Maple sap can be used to make more than syrup; boiling the syrup longer turns it first into maple candy and then maple sugar once it’s boiled enough to crystallize.
Although CNC doesn’t make maple syrup to sell (unless there’s an extremely productive season), it’s still something the staff there want to teach about.
It teaches about how the process of photosynthesis works, Johnson said, and also helps teach about the roles trees play in the world, especially about the relationship between people and food.
“It’s helping make people aware of the value of these trees,” Johnson said.
There’s also a historical component.
“It wasn’t until the Europeans came over to America that American Indians showed settlers how to make maple syrup,” Johnson said.
Although the right weather conditions do occur in Europe, sugar maples are only native to the Americas, she said.
For the American Indians in the region, maple trees were the main source of sugar before sugarcane and sugar beets were cultivated here, Johnson said.
CNC still has a few chances left for people to experience making maple syrup for themselves. Another public program is scheduled for March 20 from 1 p.m. to 3 p.m. On March 19, a special session will be held for any scouts (boy or girl) and their families. There are still chances for school groups to come out as well, Johnson said.
Given the early thaw this year, the syrup season isn’t expected to last long.
“I would think that this year we would be done by April 1,” Johnson said.