Making maple syrup has a lengthy tradition in Northeastern North America. Long before anyone wrote about it, Native Americans gathered sap from cuts made in maple trees that they boiled to concentrate the sugar. Once Europeans arrived in North America, they too began collecting sap and boiling it in large pots, evaporating the water to make syrup and sugar.
The equipment and techniques for making maple syrup have evolved over time, but the basic principle is the same. Maple sap is mostly water that contains a small amount of sugar and minerals.
By removing the water, the sugar can be concentrated to create sweet syrup or even granular sugar. Traditionally, this was accomplished by boiling the sap for long periods of time.
If you have access to a maple tree, you can make a little bit of syrup at home. The process is simple. Collect sap from a maple tree in winter or spring (before the leaf buds begin to swell) and boil it to seven degrees above the boiling point of water.
A digital candy thermometer is handy for getting the temperature right. Foam forms on top of the sap as it boils, so you need to occasionally add a few drops of defoamer. Traditionally, people used a little butter or cream, but commercial defoamers are available that are made from vegetable oils.
It takes a lot of sap and a lot of boiling to make even a pint of syrup. How much sap, you ask? That depends on the sugar content of the sap, which varies.
In 1946, a University of Vermont educator named C.H. Jones devised a clever formula (known as Jones’ Rule of 86). Simply divide 86 by the sugar percentage of your sap and that will tell you how much you will need to make a gallon of syrup.
Two percent sugar content is considered good, and according to Jones’ rule, it would require 43 gallons to yield one gallon of syrup. But sap often has less than two percent sugar content. One percent or even less is common. Last year, there was a lot of .7 percent sap in my area, which would require 123 gallons of sap to make a gallon of syrup.
If you are wondering if there are shortcuts, the answer is yes, but they will cost you money. Let’s start by replacing your spaghetti pot with something called an evaporator, which is a purpose-built contraption of one or more pans that sit on top of a fire box called an arch.
At its simplest, an evaporator can have a single shallow, flat pan, but most are more complex. A typical evaporator has a back pan, also known as a flue pan, with deep channels (flues) which increase the surface area for heating the sap, improving the efficiency of the evaporator.
The flow of sap into the back pan is controlled by a float valve, which is set to maintain a specific level in the pan. As water evaporates from the sap, the float drops, opening the valve and admitting more sap to the flue pan.
After boiling vigorously in the back pan, the concentrated sap flows into one or more flat-bottom pans, called syrup pans, that often have partitions, creating something of a maze that the sap flows through.
As the sap winds its way through the maze, it loses more and more of its water to evaporation.
At the end of this maze is a thermometer and a valve. Here, the sap will be the most concentrated. When it reaches 7 degrees above the boiling point of water, the valve opens and syrup pours into a bucket. This is called a “draw.”
The draw continues until the temperature on the thermometer falls back below the magic 7 degrees. At this point the valve is closed and the process repeats. A hydrometer is floated in the syrup to confirm that the syrup is dense enough to meet the legal definition of syrup.
But where will you get all of the sap necessary to make that much syrup? Today, plastic tubing has replaced the iconic sap buckets in most large maple operations. Not only do they reduce the labor needed to gather the sap, but they can also be connected to a high vacuum pump that can more than double the yield of sap per tap.
Sugar maples and the closely related black maples are the best trees for maple syrup production because of their sap’s high sugar content. Red maples work almost as well, and silver maples will produce useable sap but have a lower sugar content and may produce more niter (which contributes to sugar sand).
In fact, sugary syrup can be produced from other trees, including birch and walnut, which I hear are quite delicious.
People who make maple syrup are called sugar makers, and the places they make syrup are called sugarhouses (or sugar shacks). Some are hobbyists who tap just a few trees; others have commercial operations with tens of thousands of trees.
Regardless, most sugar makers are very friendly and generous, and many real characters. It is a long-standing tradition for sugar makers to visit one another and socialize whenever they aren’t making syrup themselves.
Often, they’ll just drive around until they see steam billowing from somebody else’s sugarhouse. If the owner can spare the time, conversations can last for hours and will almost certainly include the weather and how much syrup they have made to date!
Who makes the most syrup? Canada produces about 70 percent of the world’s maple syrup, mostly in Quebec. Coming in second place (there really isn’t a third place), the United States produces the rest.
Vermont is the clear winner among the states, producing more than twice as much as second-place New York. Quality is more important than quantity, but I can’t offer that as a consolation prize because great maple syrup is found everywhere it is made.
This essay by Greg Smith, Director of the Bureau of Historic Preservation, first appeared on the State Parks & Historic Sites Blog.
Illustrations, from above: firing an 1890s sugar boiler in the Adirondacks (photo by John Warren); and the author’s more modern evaporator and sugar house at work.
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