ORRINGTON — Warm steam rising from a 15-gallon evaporator greeted visitors attending the March 22 MapleFestival/Irish Celebration, held at the Curran Homestead Living History Farm & Museum on Fields Pond Road in Orrington.
The event featured different activities, from learning how maple sap becomes maple syrup to checking out small farm animals in the Curran barn to watching Dwight King and Pat Roy at work in the blacksmith shop. The first springtime activity that visitors encountered was boiling maple sap inside the sugar shack.
Wispy steam rose around Bob Croch of Dedham as he watched the evaporator boil maple syrup. “We are using an old [wood-fired] barrel stove that was made by” a former resident of the Curran farm, Croch said. The farm is now preserved by the non-profit museum.
The barrel stove had been modified to hold the evaporator, which was stored in the sugar shack’s rafters. According to Croch, the evaporator was boiling sap from “about a dozen taps here and about 20 over in Dedham.
“The [maple] sap in our region runs between 2 and 3 percent, sugar content,” he said. “Most of the early season sap runs close to 3 percent, so you can boil 29 gallons of sap to get 1 gallon of syrup.” If the sap’s sugar content is closer to 2 percent, boiling 40 gallons to produce 1 gallon of maple syrup is normal, Croch indicated.
“In a good year, the maximum you would get would be 40 gallons [of sap] in one tap in a nice-sized, healthy tree,” he said.
So far in spring 2014, “the sap is running very sporadically. It’s shutting off, then turns on,” Croch said. He explained that the internal temperature of a maple tree must reach 40 degrees Fahrenheit before sap starts rising in the tree.
When a maple tree warms internally, a chemical reaction occurs. In the fall, a dormant tree converts sugar to starch, which is “stored through the winter,” according to Croch. In late winter and early spring, a maple tree starts converting starch to sugar at the 40-degree point; “this causes a pressure gradient that causes sap to rise in the tree,” Croch said.
“As soon as the tree’s internal temperature reaches 45 degrees, that chemical reaction stops,” and maple taps no longer yield sap, he said.
On the front porch of the Curran farm house, Judith Frost Gillis of Orrington showed children how to process foods as their great-grandparents might have done 70-80 years ago. Kept busy by young hands eager to handle various kitchenware, Gillis said, “We are using 1930s’ and ’40s’ vintage kitchenware. It came then with red handles or green.”