In Vermont, maple syrup season typically starts in March and lasts four to six weeks. Sap runs when nights drop below freezing and days warm to at least 40 to 45°F. In most of the state, the season ends in April, when the weather stays warm and the trees start to bud.
The season at a glance
- Starts: typically in March.
- Lasts: about four to six weeks.
- Needs: nights below freezing and days of at least 40 to 45°F.
- Ends: in April for most of Vermont, once it stays warm and the trees bud.
Why it needs freezing nights and mild days
Maple trees store starch in their wood during the growing season. When the wood warms to about 40°F, that starch turns into sugar and moves into the sap.
The freeze and thaw is what gets the sap moving. Swinging between freezing nights and mild days builds pressure inside the tree, and that pressure pushes sap out of the tap holes. After a freeze and thaw, sap can keep flowing for 30 to 72 hours, and the next freeze and thaw can start a new run.
Both halves matter. The temperature has to dip below freezing, usually overnight, then climb back above it, usually in the daytime. If it stays frozen, or stays warm, the sap doesn't run.
When it starts
In Vermont, the season usually gets going in March. Sugar makers tap their trees in the months leading up to it, so they're ready for the first sap run.
The exact timing varies a lot, even in a state as small as Vermont. A sugarbush is the grove of maples a sugar maker taps, and where it sits makes a real difference. Producers have a short window to bring in their whole crop, and as Vermont producers like to say, to be a sugar maker is to be an eternal optimist.
Nearby, Maine shows how much location matters. The University of Maine says the freeze and thaw cycles there typically run from mid-February to early April in the southern part of the state, and from mid-March to late April in the north.
For many sugar makers, the start has been creeping earlier. In one study cited by the USDA Forest Service, 59 percent of the maple producers surveyed said they had already seen earlier tapping seasons. The Vermont Maple Sugar Makers' Association notes that the season is highly sensitive to temperature changes of only a few degrees.
What happens while it runs
Sap doesn't keep, so sugar makers boil it as soon as they can. Drive past a sugarhouse during a boil and you'll see maple-scented steam rising from the roof. Every run has to be boiled. It takes on average 40 gallons of sap to make one gallon of syrup, so there's a lot of boiling to do in a few short weeks.
When it ends
The season ends once the nights stop freezing for more than a few days. Around the same time, the trees start to bud.
Budding changes the sap. Syrup made as the trees break bud picks up an off flavor known as "buddy." Vermont's rules count buddy flavor as damage, and Grade A syrup has to be free of damage, so that late syrup can't be sold as Grade A. Sometimes the warm days arrive early, and the season ends sooner than anyone hoped. Then the spouts come out, so the trees can heal.
The work keeps going after that: replacing lines, cleaning equipment and looking after the forest until the next March comes around.
What changes over the season
Syrup gets darker and stronger as the weeks go by. Early syrup is usually Golden, with a delicate taste. Amber, with a rich taste, usually comes about mid-season. Dark follows with a more robust flavor, and Very Dark comes at the very end. So the color of your syrup is a clue to when the sap ran. Our guide to the grades has more on each color class.
Sticky comes from two of those moments. Amber is warm and smooth with caramel notes, the one that goes on everything. Dark is deep and robust, built for cooking and baking. Both come from one Vermont forest and are boiled over a wood-burning fire.
Want to see it for yourself?
The Vermont Maple Sugar Makers' Association coordinates Maple Open House Weekend on the first weekend of spring each March, with about 100 sugarhouses to explore. Plenty of sugarhouses welcome visitors year round, too, and the association's Maple Meander passport program can help you plan a visit.
