How Sweet It Is

By Ilene Dube



While 75 percent of U.S. maple syrup comes from New York and New England, the maple syrup producing region extends south to Tennessee and west to Minnesota. In New Jersey, there are state-wide opportunities to witness maple syrup being made, from tree tapping to sap boiling.

On a late fall day, Stony Brook-Millstone Watershed Association Education Director Jeff Hoagland and Education Manager Pat Heaney led a visitor around the Watershed Reserve on Titus Mill Road in Hopewell Township to see some of the maple trees that would be tapped in January. When done properly, tapping maple trees does no harm.

Hoagland describes maple sugaring as a celebration bookending the winter solstice. “It’s still winter on the calendar, but we can hear the tree frogs and birds waking.”

The Watershed only taps about 12 trees, and for educational purposes only. A maple sugaring hike and brunch will be offered March 3, 9:30-11:30 a.m., during which participants will visit tapped trees, learn about the process to convert maple sap to syrup and see the evaporation station before indulging in pancakes slathered with syrup from the Watershed Reserve’s trees. Register online at

“We’re bringing science to life,” says Hoagland. “There’s a magical quality to it. People come here for the wonder—we want them to understand the science and the issues, and learn what they can do on their own property. It’s a hands-on immersive experience, identifying the trees, seeing their layers, hearing Native American stories.”

One such tale is that the creator gave the maple tree as a sweet gift. At that time, all you had to do was break off a branch and the syrup flowed like honey. But soon the village was in disrepair, the fields were overgrown, and the fires had grown cold. The creator sent an ambassador to find out what had gone wrong and the ambassador found the villagers lying on their backs, drunk with maple syrup. The syrup had fattened them up and they could not move.

To teach them a lesson, the creator watered down the sap. Now it would only flow once a year, and in order to harvest it they would need to build buckets from birch bark. They would need to gather wood to make fires to boil the sap.

Hoagland, who has been with the Watershed for 33 years, first cooked sap over a wood fire in 1984 for the Watershed’s program on Colonial-era techniques. Since then, the process of tapping trees has not changed much, although one year he experimented with a batch of maple sap beer. In the early years, the spile, or spigot for extracting maple, was made from staghorn sumac. Now it is made from metal or plastic. And whereas Native Americans used dugout tulip trees for buckets and gourds, metal buckets are used to gather sap.

It takes about 40 years for a tree to reach the point at which it can be tapped healthily, estimate Hoagland and Heaney. While climate change may alter the timing of the sap run (see below), Hoagland says you know the tree is ready when you see the buds open—that’s when the sugar has gone back up into the tree.

Below freezing temperatures at night and above freezing during the day cause the expansion and contraction that moves the sugar up. “It used to be at the end of February to mid-March—now it can be as early as January,” says Hoagland. “The dramatic change in climate makes the tree more vulnerable to predators such as tent caterpillars and gypsy moths.”

Landscape design has evolved for maple sugaring. “Everyone who built houses in the 18th and 19th centuries planted a beautiful shade tree over it,” says Hoagland. There are two such maple trees on the former residence on the Watershed Reserve, but after 20 years of continuous tapping, these trees are being given a break.

“You can do three taps a year without doing harm to the tree,” says Heaney. “That’s the industry standard.” Drilling is done on the south side of the tree, where the sap has warmed in the sun. The tree will heal within two years, adds Heaney.

The yellow-bellied sapsucker—“nature’s driller”—is another sign that it’s time to tap the tree. Squirrels, meanwhile, scurry to the end of the branches to get what everyone else has missed. “We all live happy together,” says Hoagland.

“We’re the greedy ones with the big drill,” adds Heaney.

At the Watershed, the sap is boiled into syrup on the cook stove in the new Education Center. “It’s a great wallpaper remover,” jokes Hoagland of a process that yields a tremendous amount of steam. “With two burners going, you can set off the alarm—and then feel rain coming from the ceiling. We open the windows and clouds form.” Pictures of the classical sugar house show it with plumes of steam evanescing from the windows.

Before the Civil War, when no other sweeteners were grown in the U.S., maple sugar was a big industry. Native Americans made maple sugar, which has a longer shelf life—maple syrup requires refrigeration. When cane sugar, a more cost-effective sweetener, began to be imported from the Caribbean, maple sugar production took a nose dive.

Other trees, such as birch and black walnut, can also be tapped for syrup but may not be to everyone’s taste, says Hoagland. And trees such as the invasive Norway maple produce a sap with undesirable characteristics, according to the Cornell University website.


The sugar maple is first choice for making maple syrup as there is more sugar in the sap compared to other species, such as red or silver maple, meaning it will take less sap to produce a gallon of syrup. In the fall, maple trees re-absorb chlorophyll, but they don’t let it go to waste—the color that you see is the pigments that aren’t re-absorbed. Trees with higher sugar content tend to have the brighter foliage in the fall.

The sugar maple tree stores starch in its trunk and roots before winter; the starch is then converted to sugar that rises in the sap in the spring. Freezing nights and thawing days make for heavy sap flow. The trees are tapped by boring holes into their trunks and collecting the exuded sap. The sap is then boiled to evaporate much of the water, leaving the concentrated syrup.

The sap must be filtered before boiling, then again halfway through the boiling process to remove bark, ants, moths, and debris. Maple sap becomes maple syrup at 219 ¼ degrees.

A natural sweetener, maple syrup is touted as being healthier than processed pancake syrups such as Log Cabin or Aunt Jemima. Maple syrup contains naturally occurring minerals such as calcium, manganese, potassium, and magnesium, according to the Vermont Maple Sugar Makers’ Association (an organization that exists to promote maple sugar). Like broccoli and bananas, maple syrup is a natural source of beneficial antioxidants, which have been shown to help prevent cancer, support the immune system, lower blood pressure, and slow the effects of aging. Maple syrup is more nutritious than other sweeteners, packing one of the lowest calorie levels, and has been shown to have healthy glycemic qualities. In addition, researchers have found that pure maple syrup contains phenolic compounds, commonly found in plants and agricultural products such as blueberries, tea, red wine, and flaxseed. Some of these compounds may benefit health in significant ways (see charts).

Maple syrup can also be used as a skin tonic, according to Maine Maple Producers, which claims that maple syrup can help to lower skin inflammation, redness, blemishes, and dryness. Combined with milk or yogurt, rolled oats, and raw honey and applied as a mask, the mixture can hydrate skin while reducing bacteria and signs of irritation.

And the amber-colored liquid is not just for pancakes and waffles. Maple syrup can be substituted for sugar in baking, and is used to flavor everything from bacon to chicken, salmon, and carrots.

On a less-than-sweet note, climate change is negatively impacting maple sugaring. As temperatures have climbed, the tapping season in New York and New England starts about eight days earlier and ends 11 days earlier than 50 years ago, according to Princeton-based Climate Central. Higher temperatures mean less sugar in the sap, and so more sap per gallon of syrup is required. During hot periods outside of winter, the sugar within the sap can be reduced by 40 percent.

A century ago, 80 percent of global maple syrup production was based in the U.S., with 20 percent in Canada. Those figures are now reversed, with climate change likely playing a role, along with advances in sap collecting and Canadian subsidies.

With no change in greenhouse gas emissions rates, Climate Central estimates that tap season may start 30 days earlier by 2100.


Charlize Katzenbach, Princeton University Class of 1971, farms the property she grew up on in Hopewell Township. At Sweet Sourland Farms, Katzenbach has a few hundred sugar and red maples on tap. She uses a wood-fired evaporator in the sugar house to make about 50 to 100 gallons of pure maple syrup a year, depending upon weather conditions. Sap is collected with a tubing on a vacuum system at sundown each day, and boiled at night.

Katzenbach and her wife, Bru, experienced their first taps at Howell Farm more that 30 years ago. After seeing a demonstration there, the Katzenbachs purchased a spile, the tapping device used to direct sap from the tree into a collecting vessel, and gave it as a birthday gift to a friend who had 150 maples on his property. When the friend relocated to New Mexico, the Katzenbachs acquired his stainless-steel evaporator machine.

Over the years, the Katzenbachs have refined the process by which the sap is collected, using tubing and a vacuum pump to bring it uphill to a tank in the sugarhouse that Charlize built for the purpose. The multi-chambered evaporator converts the sap to syrup, powered by waste wood from the farm’s sawmill.

The maples on the 27-acre farm, which was featured in the documentary Sourlands, are indigenous to the area. Some are hundreds of years old, some are 40 to 50 years old. Sweet Sourland Farms sells its maple syrup, but suggests visiting the other farms listed to view the operation.

Sweet Sourland Farms, 90 Lambertville-Hopewell Road, Hopewell;


Sign up for maple sugaring at Howell Living History Farm, where there are 150 maple trees for tapping, and you’ll be put to work cutting firewood for sap boiling—the first step in preparing for a sugaring operation. Participants will keep warm by sawing wood with a two-person saw and splitting wood with a wedge and hammer, and will learn about varieties of wood and their use for fuel, buildings, fencing, and/or tools. They will also learn to identify a sugar maple tree, tap the tree, and taste the sap, if it is flowing. Visitors may also load some of the sap on a horse- or oxen-drawn wagon to take back to the farm for boiling in an evaporator. Then, using wheat grown on the farm, participants can help grind and sift flour and take a turn churning butter. Learn about the conveniences of a circa-1900 kitchen while you sample a pancake topped with homemade butter and maple syrup.

Howell Living History Farm, 70 Woodens Lane, Lambertville;

Additional Maple Sugaring Options Include:

Environmental Education Center

Environmental Education Center, 190 Lord Stirling Road, Basking Ridge; A 90-minute program is conducted at the Sugar Shack, a half-mile hike from the EEC. Participants are advised to dress appropriately for the weather conditions. Boots are recommended as the trails can be wet, muddy, and/or covered by snow.

Duke Farms

Maple Sugaring Celebration at Duke Farms,
1112 Duke Parkway West, Hillsborough;

Tenafly Nature Center

Tenafly Nature Center, 313 Hudson Avenue, Tenafly; Discover the history of syrup making and how technology has changed the way sap has been gathered over the centuries. Sessions are one hour long throughout late winter—check website for schedule.