Maple Sugaring

“There is in some parts of New England a kind of tree… whose juice that weeps out its incision, if it is permitted slowly to exhale away the superfluous moisture, doth congeal into a sweet and saccharin substance.”

Robert Boyle, 1663

I tromp through the snow to the tin bucket hanging against the tree. Yesterday the bucket was empty. Today I find gallons of crystal-clear water with the slightest tinge of bluish green. I am astonished, knocked back in a way that 19th-century folk must have been when seeing an electric light for the first time. Magic. I lift the bucket to my lips. The glacial-cold sap spills down my chin. The taste—the perfect hint of sweetness, like drinking water after sucking on caramel candies.

I pour the sap into my gathering bucket and trudge over to the next tree. Some buckets hold only a few inches of sap. Others overflow. I feel drops on my shoulder. I look up to catch the next drop on my face. The maple overhead lost some of her crown in the last ice storm. Sap drips out of the severed stump twenty feet above me.

Ah, sugaring season in Vermont. We tapped out in late February during the first spring thaw. I was given terse instructions and handed a drill, a hammer, some nails, some spouts, some hooks, and a pile of galvanized buckets. I faced the forest.

I can pick out a maple leaf but what does a maple tree look like in winter? Opposite branching, right? This one? No, that’s an ash. That one? Oak, actually. There? Basswood. I know it’s not those white pines. What about this one—smoother bark for her size, mottled with gray-green lichen, meandering branches not as desperate to shoot skyward. I see scars the size of the drill bit, chest-high up the trunk. I’ve found my maple.

I take stock of the tree’s southern face, her northern face. I look up for any deadwood. I look down for main root veins. I use the tap holes of past sugaring seasons as my guide, careful to aim at least a few lateral inches from any scar. I fumble for my drill, lean it against the bark, angle it slightly up the trunk, and pause—it feels wrong. I step back again, call over, confirm that yes, she is a maple tree and yes, I should tap her. I go in again with the drill. I churn through the bark but hit resistance less than an inch in. I lean against the drill and push it a couple inches into the tree.

By the time I clear out the wood shavings, a drip of sap beads up at the hole’s edge. I taste it, curiously, getting mostly maple bark. I take a tap—a hard-plastic spout—and hammer it into the tree until I feel a thud. I attach a bucket to the clip and affix a lid to keep out snow, rain, and debris. Walking to the next tree, I hear the light tip, tip, tip of the sap dripping into the bucket.

We tapped out a couple hundred maples—some with buckets, but most with sap lines. Buckets need to be emptied every day the sap runs whereas lines carry the sap from the tree straight to the sugar house. The rubber tubing crisscrosses the woods from tree to tree, emptying into a larger main line following a small creek downhill to the sugar house. Setting them up was harder than it looked. To function, every tap further up the line must be set at a higher point so that gravity pulls the sap to the main line. And the line must be kept taut. Sagging lines will freeze solid and hold back the sap. 

It was adventurous work—snow many feet deep, creek crossings, steep hillsides from one tree to the next, the small pieces necessitating bare hands in the freezing air. My small imperfections from one tree to the next add up until I’m reaching well over my head to put in the last tap. I don’t know how we’ll take them out. The ground will be several feet lower after the snow melts.

For the trees around the house, we used buckets. Close at hand for gathering, more aesthetically pleasing, and fewer obstacles of long-reaching lines wrapped around the house. The best parts: ending a jog with a long drink of sap straight from a 5-gallon bucket; dipping my face straight into an overflowing bucket too cumbersome to sip; finding a block of ice after a cold night and negotiating its heft to get to the concentrated sap underneath.

Whether by bucket or line, the sap ends up at the same place—a 300-gallon tank in the sugar house, a magical place built for one purpose. In its center lies the two-by-eight-foot evaporator—two long pans atop a long wood furnace. An open-air cupola juts above the roof to allow steam to escape. Abutting the sugar house is the wood shack, nearly half the size of the sugar house itself. After a good sap day, we’ll boil.

Maple sap is 2-3% sugar. Gatorade is 6% sugar. Sodas and fruit juices are 11% sugar. Maple syrup is 66% sugar. That means for every forty gallons of sap, we’ll make a gallon of syrup. The other 39 gallons are boiled off as steam.

A day of flowing sap means a long night of boiling. The longer sap sits unboiled, the more it will ferment, and the enemy of quality syrup is fermentation. The moment sap leaves the tree, the microbes on the bark, in the tubes, and in the air start to break the sap down, so it is imperative to boil it as soon as possible. If left too long, the sap will get an “off-taste”, vinegary almost. We had a spate of very warm days at the end of the season and you could smell the difference in the steam. From sweet to almost sickly.

During the best weeks, we were pulling in well over a hundred gallons of sap every day. That’s a lot of steam to boil off. When it’s going, the furnace swallows huge logs every few minutes. The sap boils furiously like something out of Yellowstone, and the room fills with steam. At its best, the small evaporator here can boil off 30 gallons of sap in an hour, more than an ounce of water every second. 

The pans are kept shallow, only an inch or two deep, with the valve set to run sap into the pans from the tank at the same rate that it boils off. If the sap goes too low, the stainless steel pan will be destroyed in seconds, the sugar scorched on, the pan’s joining solder melted, and the fire bursting through. The other thing to watch out for is foaming. Just as a pot of boiling pasta will foam, the sap can foam up and over the sides. Old-timers would hang a strip of bacon from the ceiling so that if the sap foamed too high, it would touch the bacon, and the fat would cut the surface tension, knocking the foam down. We would drop in a bit of kosher oil instead.

The evaporator pans are tiered. The fresh sap flows into the upper, larger pan, where the most Vesuvius-like boil splashes sap over the tall edges. At the opposite corner, the now-more-concentrated sap drips into the lower pan where it’s brought closer to syrup. After two hours of continuous boiling, the syrup from this lower pan is emptied through a felt filter to separate a sandy residue from minerals that precipitated out of the solution. 

To better control the final stage, we finish the syrup over a propane stove to get it to 66% sugar. Much beyond that and the syrup begins to crystallize. We used two methods to measure the sugar content: a thermometer—water at our elevation of 1,200 feet boils at just under 210 Fahrenheit but a 66% sugar solution boils at 217; and a hydrometer, a thermometer-shaped float—maple syrup is 39% heavier than water and will push the float higher. From there, the syrup is bottled above 180 degrees to sterilize the bottle.

At best, we bottle a gallon or so every two hours. Explains why he charges $10 for one cup of the stuff, doesn’t it?

“When made in small quantities—that is, quickly from the first run of sap and property treated—it has a wild delicacy of flavor that no other sweet can match. What you smell in freshly cut maple-wood, or taste in the blossoms of the tree, is in it. It is then, indeed, the distilled essence of the tree.”

John Burroughs, 1886

All this labor, but I’ve ignored the hardest worker. Because maple syrup isn’t made in spring’s first thaw. It’s made in summer. The sun high, the air warm, and billions of maple leaves wrangle carbon dioxide and water and convert the energy of sunlight into the chemical energy of sugars. She combines sugars into starches and stores the energy in her trunk and roots. As Vermont turns from the sun, she lets her leaves fall and hunkers against the coming chill. When spring returns, she breaks the starches into sugars and pipes them back to her crown to spur her buds to burst into leaf. 

And so it goes for every deciduous tree. Theoretically, sap could be extracted and syrup made from any deciduous tree or vine. (If you cut an old wild grapevine in the spring, you can fill a water bottle in short time). We tried it out, tapping a single black walnut tree. He produced less than 10% the sap of the neighboring maples, and after we boiled down the season’s total haul of sap to a half-cup of syrup, we decided it tasted like “bad maple syrup”.

The sugar maple tree is special for the percentage of sugar in its sap and for the amount of sap that can be extracted. I still don’t really know why that is, biologically. Everyone I ask matches each other only in the confidence of their answer.

First, the empirical observations. Maple sap consistently runs only when daytime temperatures peak above 40 and when nighttime temperatures fall to 25 or below. When the highs were stuck in the low 20s, our buckets were empty for a week. In late March, with lows in the 40s, the sap stopped again. But in optimal conditions, I’ve seen single trees give more than 5 gallons of sap a day.

Here’s the most convincing explanation I’ve read for how they do it. All trees have a layer of sapwood that transports water up and down the tree. Most trees are filled solid with water. But maples are different. Their wood fiber cells are filled with gas instead of water. The trapped gas gets compressed as the sap freezes around it. When the sap melts the next sunny day, the compressed gas pushes the sap out of the tree. And when it gets cold again at night, the pressure in the cells lowers like a cold tire. Sap is sucked into the tree from the roots to fill the extra space. They say a gradual freeze at night is better than a hard freeze. If gradual, more sap can be sucked into the tree before it freezes.

Whatever the reason, maple sugaring season will run as long as the trees are caught in a cycle of thaw-and-freeze. If too many nights in a row are above freezing, the maple’s buds will swell, the sap composition changes, and the flavor is no longer as palatable. The harvest ends.

These unique conditions are why maple syrup production is localized to northeastern North America. The cold winters and long stretch of fluctuating spring extremes extend the syrup season long enough to make it worthwhile.

Then there are the different grades of maple syrup. From Golden Delicate to Dark Robust, the process is exactly the same, though the taste is wildly different. A sugar house will produce the full range of colors in a season. Generally, the color gets darker as the season progresses. The sugar in maple sap is almost purely sucrose. Those microbes mentioned above break down sucrose into simple sugars, glucose and fructose. When subject to the high temperatures of boiling, simple sugars brown like a bread crust. Sucrose will not. As a season progresses and the weather warms, microbe activity increases, and more sucrose is broken down before the sap can be boiled down. Additionally, the sugar content of sap trends down toward the end of the season, meaning it has to be boiled for longer to get to syrup, eventually lending the syrup a darker color and a more “robust” taste.

“Who would not marvel to see realized in the frozen forest of Canada, those enchanted pictures that the ancient poets have left us of the golden age, when they painted for us the trees distilling honey through their bark?”

Henri-Louis Duhamel du Monceau, 1755

Compared to the tree’s work, the “labor” we put into sugaring feels more like play. Or like stealing candy from a tree. All we do is drill a hole with our electric drills and wait for the sap to come pouring out. Even the boiling, well, after I volunteered for a few late-night boilings, Lauren eventually realized that “boiling” mostly means “eating hot dogs and drinking beer at the sugar shack.”

The sugar house is the cultural hub of sugaring. It can be in the single digits, snowing, dark, the wind howling, and you come upon this little shack with this warm glow inside, sparks shooting out the chimney stack, and you walk inside and it feels like a steam room. No electricity, only a propane lamp. The fog hangs so heavy it drips from the ceiling and you can barely see from one side of the small shack to the other. Plus there’s sugar in the steam. Ah, that mapley smell of sweet steam coming off the evaporator.

After a long winter, neighbors come back together for the nightly boils. On our small-scale production, there’s plenty of time for stories of past sugaring seasons. Like shelling beans or knitting scarves, there’s something about engaging in simple tasks that brings the stories out of people.

Ah, the joy of an abundant harvest. No other time would I so prodigiously churn through a $10/cup food. We sample hot sap from the upper pan, from the lower pan, from the filter. We boil syrup way past 217 Fahrenheit and pour it onto snow. It congeals in seconds into a taffy-like candy and we roll it onto sticks, “Sugar on snow”. We fill a small tub with sap, stick it in the upper pan, and boil eggs and hot dogs, “Sap dogs”. Even Lauren jumps in on the action, topping her sap dog with maple syrup.

We boil through the day’s harvest of sap and then let the fire die down. We stumble out and get smacked in the face by the screamingly refreshing cold air. I walk back to our cabin with the moon and stars reflecting off the white snow, so bright that I cast a dark shadow. Now that I’ve tasted freshly made, still-hot syrup, I don’t know if I can ever go back to pouring the stuff onto pancakes. Feels like a sacrilege. Outside of sugaring season, I may forever take syrup straight. Warm it up a bit and sip a teaspoon at a time.

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So that’s maple syrup for you. Concentrated sap from a maple tree. Amazing if you’re a frontiersman struggling to survive the winter. Terribly impractical if you’re just trying to sweeten something in the age of industrial agriculture and global trade, when sugar cane can be grown on plantations in Brazil, shipped to New York, and trucked into the Green Mountains. Or sugar beets from North Dakota for that matter.

A quick search of bulk retailers finds it costs $0.87 to buy 2,000 calories of sugar cane. $0.91 for corn syrup. $1.98 for honey. Maple syrup? $5.78 for 2,000 calories was the cheapest I could find. The syrup we made costs $21.95 for 2,000 calories.

There’s a reason grocery-shelf mainstays Log Cabin, Mrs. Butterworth’s, and (formerly-known-as) Aunt Jemima are made with corn, not maple sap. (I only recently realized they all label themselves “Original Syrup.”) Maple syrup substitutes have been manufactured for decades. In Helen and Scott Nearing’s The Maple Sugar Book, published in 1950, they comment that “The blended syrups and the chemical flavorings with which chain stores have been supplying [people] do not meet the demands of those who have once enjoyed the true maple flavor.”

This wasn’t always the case. In colonial days, maples were the main source of sugar for Canada and the northern United States. Thomas Jefferson famously supported cultivating maples to supply 100% of the country’s sugar consumption. To buy maple sugar was once a political act, as cane sugar was associated with the slave economies of the West Indies. Jefferson wrote to the abolitionist, Benjamin Rush, “What a blessing to substitute a sugar [maple sugar] which requires only the labour of children, for that [cane sugar] which it is said renders the slavery of the blacks necessary.” The 1844 Vermont Farmer’s Almanac exhorts “Stick to the maple; and so long as the maple forests stand, suffer not your cup to be sweetened by the blood of slaves.”

Peak production of maple sugar in the United States was in the 1860s. In those days, most of it was boiled past syrup down to sugar crystals. But then, “beginning in the 1870s the price of cane sugar, and later of beet sugar, was cut by the introduction of new processes and machinery. By 1875, cane sugar began to undersell maple. Since 1885 maple sugar has gradually come to be considered a confection or a luxury article.”

While those alternatives—sugar cane, sugar beets, and corn—are today intensively cultivated on a grandiose scale, maple syrup is still stubbornly difficult to industrialize and that is reflected in its price.

“Hurrah for the Sugar-Orchard! Let the sunny South boast her sugarcane, and the West her beet or corn-stalk sugar; but we Green Mountain Boys will stand by the rock-maple.”

Vermont Register and Farmers’ Almanac, 1844

One of the most romantic traits of maple syrup is its resistance to human cultivation. You can’t clear land, plant maple trees, and expect a harvest in a few months. It takes forty years for a sapling to grow to a tappable size. And twice that long until the sap flows heavily. Stories of planting a sugar maple orchard are few and far between, usually reserved to royal estates, and usually ending in failure. No other ubiquitous food I can think of is produced with less human cultivation. Even fish are farmed.

The maple tree family, Acer, is diverse and widespread across the northern hemisphere. The sugar maple, Acer Saccharum, is native to the northeast of North America. As a thriving understory tree, they are typical of mature hardwood forests, where they meander under the canopy, waiting for a break in the tallest trees to shoot skyward. In a clear-cut, they will lose out to more opportunistic species. They need cold winters and are rarely found where temperatures never dip below 0 degrees Fahrenheit.

At the end of the summer, the leaves are shut off from the branches and they shift away from building chlorophyll to making antioxidants similar to those in egg yolks and carrots and beets. The leaves show off their range from lemon-yellow to orange to fiery-red, the most iconic addition to New England’s autumnal forests.

Compared to other maples, the sugar maple’s wood is significantly harder and more resistant to rot. Another name for the tree is hard maple. Indeed, I really had to lean into the drill to get it a few inches into the tree. By comparison, the black walnut we tapped—not a soft tree itself—felt like drilling into butter. Consequently, the sugar maples are long-lived trees. 200, 300, sometimes 400 years. Some of the trees we tapped on Taft Hill Farm were probably alive when Aaron Taft, great-grandfather of President and Chief Justice William Taft, settled the hillside. It’s likely that some of the trees have been tapped over a hundred times.

Everyone wants to know if tapping injures the tree. The short answer is, no one really knows. The longer answer is, it’s safe to say she would rather not be drilled into every spring, dozens of gallons of hard-earned sap drained away. But given the longevity of these maples and the longevity of the sugaring tradition, they seem to get along just fine. Traditionally, a maple should have a trunk diameter of over 12 inches before it is tapped. A maple is tapped twice if over an 18-inch diameter. And sometimes three taps if over 24 inches. By the winter, the tap holes have scarred over completely.

The practice has come a long way from the days of snowshoeing through the sugarbush to empty a thousand buckets every day onto a team of horses pushing their way through 8-foot drifts of snow. Today, vacuum tubing can suck more sap out of the tree and deliver it to a central facility. Reverse osmosis can concentrate the sap before boiling. Trucks deliver sap or syrup over reliable roads. But no machine can tap hundreds or thousands of trees. Tending to an evaporator with cords and cords of wood is still careful work. The size of a maple bush is constrained by the nuances of the forest. The largest operation I heard of in our area of Southern Vermont covered 22,000 trees. Even that took five people only four days to tap out. There isn’t much room left for machines to improve efficiencies.

Industry demands full employment of capital. Steel mills and Wal-marts are open 24 hours a day, whereas maple groves and sap evaporators lie untouched 10 months of the year. Modern employment calls for predictability. But a week can go by without sap flowing.

“The most delightful of all farm work, or of all rural occupations, is at hand, namely sugar-making… Huge kettles or broad pans boil and foam; and I ask no other delight than to watch and tend them all day.”

John Burroughs, 1881

It seems when an industry is no longer commercially feasible, the leftover chaff feeds a resilient culture. And it seems when something can only be done in one place, that something becomes a centerpiece of the place’s identity. The Canadian flag isn’t just any old maple leaf. It’s a sugar maple leaf. (While Vermont produces more than half of the U.S. supply of maple syrup, Quebec produces more than 70% of the global supply). No matter that you can buy a gallon of Log Cabin Original Syrup for $10, people in the Northeast are still going to buy maple syrup. It’s about taste, of course. But really, it’s about pride, with some self-admitted snobbery mixed in. Mostly, it’s about feeling a connection to the community, to the land, to the history of a place.

The same reasons that make it impossible for maple syrup to compete with 16,000-acre cornfields make it perfect for the home or the community. You can’t drive far in Vermont in March without seeing galvanized buckets lining the roadway or hints of sap lines in the forest. All it takes is a little time, some sugar maples, some buckets, a drill, and a stove, and you got yourself some homemade syrup.

Sugaring season is at a time when people are looking for a diversion. Near the end of a long, cold winter, the nights still long, snow still blanketing everything, any fresh green a distant dream, nothing to do, the first thaws only bringing wetness and uneven footing—that’s sugaring season.

“Sugaring comes in a season of the year in which nature provides no sustenance to man or beast… The time required for labor, if it deserves that name, is at a season when it is impossible for the farmer to employ himself in any species of agriculture.”

Benjamin Rush to Thomas Jefferson, 1791

The process from sap to syrup is as simple as could be. Lauren and I boiled down that half cup of black walnut syrup from one tree, one bucket, with one hot plate. 

In contrast, to process corn into sugar is simply impossible on the home scale. First of all, you can’t really grow corn on a “small scale” given the finicky nature of corn pollination. So you clear a large flat plot of land, till it up, pump it full of fertilizer (corn is a notoriously heavy feeder), pray the tall stalks aren’t knocked over by wind or hail, fight through razor-sharp leaves to harvest it all, and build a big concrete storage facility to dry the husks out for many months and keep the rodents away. You’re left with dry corn kernels and you ask yourself how am I supposed to put this on my pancakes? Then you buy a big ol’ mill to grind the starch out of the corn and build a big ol’ lab to send that starch through a series of acids and enzymes, demineralize it using something called ion-exchange resins and then run it over immobilized xylose isomerase. Just don’t ask me where you find all those enzymes and isomerases, let alone “immobilize” them.

My point isn’t about the nutritional quality of one versus the other. While maple syrup has a sprinkling of minerals and antioxidants and a lower glycemic index, don’t fool yourself into thinking there’s a meaningful difference between ingesting a cup of maple syrup or a cup of corn syrup. My point is about how one is only possible on an industrial scale. While the other is reasonable to make in your backyard.

The details have shifted, but compared to how other foods are gathered, grown, or processed today, someone making maple syrup a thousand years ago would probably recognize the modern sugaring process. Immigrants in New France and New England learned the practice from the indigenous peoples. Instead of electric drills, they used hatchets. Instead of galvanized or plastic buckets, they used buckets made of birch bark. Instead of stainless steel pans, they dropped fire-heated stones into the sap or they let the sap freeze and discarded the ice. But the principles have stayed accessible.

In the age of genetic engineering, where agriculture is done in labs and plants are dissected down to their DNA, it has been refreshing to grow food where the relationship is flipped. I looked up to the grandeur of the maple tree, not the other way around. In place of chemical concoctions tailored to the exact genes of a crop sold to us by billboards, we had neighbors from the next hill over sprinkling contradictory axioms into their sugary anecdotes. We may have extracted less sugar, but our harvest was sweeter for it. 

The sugar maple forests of the northeast have been altered for ease of tapping and collecting sap—brush is kept low, trees may be thinned to make room for the crowns of the maple—but to make maple syrup is to meet the forest where she is. The weather and the trees dictate when you have sap. Whether it’s Saturday or it’s Tuesday, if the sap is running, then the buckets need emptying, the furnace needs feeding, the evaporator needs tending. To make maple syrup requires a different approach from the predictability we’ve forced onto modern agriculture and onto modern life.

“It is one of the noblest employments to assist nature in her bountiful productions. Instead of being ashamed of their employment, our laborious farmers shall, as a great writer says ‘toss about their dung with an air of majesty.’”

Samuel Deane, 1790

Or, at least, it has historically. Unsurprisingly, the human animal never stops tinkering. Researchers at the University of Vermont are doing their best to turn maple syrup into a cultivated crop. The latest idea involves chopping the top off a young maple sapling, attaching a hose to the severed trunk, and sucking the sap out with a vacuum. The researchers compare it to a sugar-filled straw stuck in the ground, the vacuum suction pulling water from the ground through the roots, through the sugar-lined trunk.

The theory is, you could have a field of maple saplings planted far denser than a forest. They claim the technique could yield ten times as much sap per acre as traditional sugaring, and the suction means you don’t have to wait for cycles of freeze and thaw to get the sap flowing. 

While the results were published almost a decade ago, I couldn’t find any instances where the technique has been used on a plantation scale. “One of the biggest challenges from that is from a marketing perspective,” a large-scale syrup maker has commented. Because maple syrup isn’t about finding the cheapest and easiest way to harvest sugar. If that were the case, maple syrup would never sell over Mrs. Butterworth’s. We still buy maple syrup for the same reason we pay more for wild-foraged mushrooms or ramps. Sugar from a forest. The distilled essence of the tree. Connected to our past the same way the electric light must have left people feeling connected to the future.

“May it long be the mission of the maple thus to sweeten the cup of life.”

E.A. Fisk, 1874

At least for now, “wild-crafted” sugaring lives on. Its easy-going culture has survived a century and a half of cheaper, imported sugar, resisting our modern axiom of efficiency at all cost. But it may not survive my lifetime. Already, the sugaring season has shifted earlier than when the Nearings wrote The Maple Sugar Book. They note the sap running until at least late April, often into mid-May, every year, less than ten miles from where we tapped out. Our last good sap run this year was March 24, the maple buds swelling before April 1.

The season will continue to shift earlier and run for less time until the valleys no longer conduct the cold winters that sugar maples need to thrive. The sugar houses will boil with steam for one last season and then they will fall quiet, one by one, up the unfrozen creeks into the mountains. Cold winters will continue further north, but the sugar maple won’t move north as fast as the climate. She is adapted to late-succession forests and doesn’t produce seed until at least 30 years old.

Maybe she’ll survive in pockets of high mountains. Maybe she won’t. She and the culture she sustains and the forests she enriches will suffer for no fault of their own. I wonder if she feels the same hard-to-articulate sorrow that her suffering is caused not by “an act of god” but by an act of man.

While she’s still here, she’ll keep on pushing out her sap to provide bees and insects their first meal of spring. And, if we treat her well, she may spare some for us, too.

“Many times I thought that if the particular tree under which I was walking or riding was the only one like it in the country, it would be worth a journey across the continent to see it. Indeed, I have no doubt that such journeys would be undertaken on hearing a true account of it. But instead of being confined to a single tree, this wonder was as cheap and common as the air itself.”

Henry David Thoreau, Journal Entry for January 18, 1859