Maple syrup is a New England favorite on everything from pancakes and waffles to baked goods and ice cream, but how it goes from tree sap to treat in those ubiquitous brown bottles remains a mystery for most people. Luckily, Phil Miller at the Bushy Hill Nature Center is willing to share his 30 years of experience making maple syrup with the curious. During Sunday open houses during maple syrup season, visitors can learn the science and history of maple syrup making, as well as taste locally-sourced syrup.

The process is pretty simple: Sap is collected from trees, and then put through a device called an evaporator, which looks like a large tank on top of a woodstove. The sap flows into a sap pan, then a syrup pan, being heated constantly as it circulates through the evaporator, thickening all the while.

There are two ways to know that the syrup is done: First, the sap reaches a temperature of 219 degrees, or seven degrees above the boiling point of water. Then, the viscosity is tested by using a hydrometer, a device that floats in a sample of the syrup placed in a beaker. If the temperature and viscosity—the thickness of the liquid—is correct, the syrup then passes through a filter tank, where wool and paper filters are used to remove the niter, or sugar sand. While niter is harmless, most people don’t want to see the little specks in the syrup. The syrup is then put in a canning tank to be bottled.

Of the 13 states that report syrup production, Connecticut is number eight in production with an average of 25,000 gallons of syrup produced in a year. Vermont, in comparison at number one, produces an average of 1.5 million gallons annually. Outside the U.S., Canada is king, said Miller; Quebec alone produces an average of five million gallons of syrup annually.

“Down this far south we make more of the dark syrup, where up north they make more of the light syrup,” said Miller.

Each batch of finished syrup is slightly darker than the batch made from sap collected earlier, reflecting how the tree is metabolizing its own sugars.

“Most people in the know prefer the darker, more flavorful, more robust syrup,” Miller said.

The Bushy Hill Sugar House made about 20 gallons of syrup last winter, and is hoping for 25 this year.

“We aim to do enough to cover our school programs,” said Miller. “We have schools that come every day in February and March. They see the process, measure trees and yields, and do volume studies with different containers. Its practical information.

“We used to do about 300 taps and we used to have plastic pipelines. Now we’re kind of old school—we’re doing just buckets,” said Miller. “We have about 150 buckets in four locations and, depending on whether the sap is flowing—for sap to flow, we need very cold weather to be followed by warmer weather—we can get a couple hundred gallons.

“We started here with a backyard rig made of cinder blocks and old roast beef pans and we had number 10 cans hanging on trees,” continued Miller. “Then we bought a used Canadian evaporator about 20 years ago. We replaced it with this one, a Leader evaporator, made in Vermont about three years ago.”

Only about three percent of sugar maple sap is sugar, so it takes about 40 gallons of sap to make one gallon of syrup. Maple sugar farming is like other farming in that it takes an understanding of the environment and the trees themselves to maximize yield. Trees that might be tapped are examined in the fall, long before the season begins. Those that look like they have suffered wind or insect damage, or otherwise show other signs of stress, are left alone.

“Because everything is predicated on sap flow, and sap flow is dependent on weather, this forces you to become the most intense weather observer, and to look at all the myriad of factors, full moon or not, ascending or dropping barometric pressure, snow cover—there’s so many factors and it’s fascinating,” said Miller. “It catches you up in it.”

Because of the extreme cold last year, the season only lasted three to four weeks. This year, if the weather pattern holds, Miller is hoping that the season will last about seven or eight weeks.

“I think it’s a pretty decent year—what would kill us is seven days of 60 to 70 degree weather,” he said.

The sugar maple is a common tree across Connecticut, enough so that students who visit the sugar house end up learning how to recognize the tree and have to find them as part of their homework. Also known as the hard maple or rock maple, the wood is used for floors, such as those in bowling alleys; furniture; and as firewood to heat homes.

Miller is also well versed in the local history of the sugar maple, and how maple syrup became a part of the local culture.

“People don’t realize that in the 19th century, particularly in New England, people stayed away from sugar cane and purposefully gravitated towards maple syrup and maple sugar, calling it the ‘moral choice,’ because sugar cane largely came from the West Indies and was made by slaves, and they did not want to support slavery that way,” said Miller. “This was the early- to mid-19th century, before the Civil War. That is when it got really popular in the northeast, because many people who were abolitionists, or leaned towards abolition and didn’t believe in slavery, did not want to support the slave industry. They preferred maple products because it was made by people who were paid for their labor.”

At various points, such as the early 20th century, Miller said maple syrup and sugar fell out of favor and the syrup was instead used for odd things such as chewing tobacco flavoring, but Miller believes that our cultural tie and attraction to the sticky sweet runs deeper than trends in taste profiles.

“This is our native sweetener,” said Miller.

“A lot of the kids that come here to visit, especially the younger kids, they get a shock when they taste it – it’s not like Mrs. Butterworths’s or Log Cabin, which are corn syrup with maple flavoring,” said Miller.

In addition to the syrup Bushy Hill produces for the school programs, some is sold from their own store during open house events.

Miller is hoping for at least two more open houses, which are held on Sundays from 10 a.m. to 2 p.m. in the sugar house, across the parking lot from the Bushy Hill Nature Center. For more information, call 860-767-2148 or visit, or just drop by 253 Bushy Hill Road, Ivoryton, on a Sunday.