Maple syrup is made by tapping maple trees, collecting the sap that runs in late winter and early spring, and boiling it until most of the water is gone. On average, it takes 40 gallons of sap to make one gallon of syrup. The finished syrup is then filtered, graded by color and flavor, and packed hot.
The short version
- Wait for the right weather: freezing nights and mild days.
- Tap the trees and collect the sap.
- Boil the sap down in an evaporator.
- Filter the syrup and grade it.
- Pack it hot and seal it.
It starts with the weather
Sugaring season is short. In Vermont, it usually starts in March and lasts four to six weeks. Sap runs when nights drop below freezing and days warm up to at least 40 to 45°F. Our guide to maple syrup season explains why it takes both.
Tapping the trees
Most maple syrup comes from sugar maples, often with some red maples mixed in. A tree needs to be about 40 years old, generally 10 to 12 inches across, before it's big enough to tap.
Tapping means drilling a small hole in the trunk and fitting it with a spout. The University of Maine's guide for backyard sugar makers calls for a 5/16 inch drill bit. A tap hole is a small wound, so sugar makers pull their spouts after the season to let the tree heal, and tap away from old holes the next year.
Operations come in every size, from a single tap to more than 250,000.
Collecting the sap
The spout sends sap into a bucket, a bag or a line of tubing. Tubing carries it to a big collection tank at the sugarhouse, either by gravity or with a vacuum pump.
If you saw sap straight from the tree, you'd think it was water. It's about 2 percent sugar, so it tastes only slightly sweet. It also doesn't keep. The University of Maine's guide puts it simply: "Sap is like milk." It sours if it sits in the sun, so it should be kept cold and boiled as soon as possible.
Boiling it down
Many sugar makers first run the sap through a reverse osmosis machine, which takes out some of the water before boiling. Then it goes into an evaporator: stainless steel pans that sit over a firebox, called an arch. The heat can come from wood, oil, wood chips, wood pellets or electricity. Each sugar maker picks what works for their operation.
Ours is boiled over a wood-burning fire. Sugar makers who boil with wood spend part of the off-season splitting and stacking it, so the fire is ready when the sap is.
As the water steams off, the sap thickens. Syrup is generally finished at about 219°F, or 7°F above the boiling point of water, which changes with elevation. By then it's about 66 to 69 percent sugar.
Filtering and grading
Syrup drawn off the evaporator looks finished, but it isn't quite. As the sap boils, sediment known as sugar sand and niter forms in it, so the syrup is filtered while it's still hot.
Then it's graded. All maple syrup sold in retail containers is Grade A, in one of four color classes: Golden, Amber, Dark or Very Dark. In Vermont, syrup is graded on color, clarity, density and flavor.
Color tends to follow the calendar. Syrup made early in the season is usually Golden, and it gets darker and more robust as the weeks go by. Our guide to the grades covers each one.
Packing it
Finished syrup is packed hot, at 180 to 190°F, to keep it from spoiling, and the containers are sealed quickly. Once you open one, our guide to storing maple syrup covers how to keep it.
Ours goes into tins, 8 fl oz or 16 fl oz. What you pour out has one ingredient and nothing added. It all comes from a single Vermont forest and is never blended. Amber is warm and smooth with caramel notes, the one that goes on everything. Dark is deep and robust, built for cooking and baking.
Our maple guide also covers why Vermont makes so much maple syrup, and our short history of maple syrup goes back to where it all began.
