Maple Syrup 101: All About Sap Collection

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Part II: The Sap Run

Once the sugarbush is fully tapped, we wait for the sap to run. For the tree to produce sap, temperatures need to cycle between above and below freezing.  Traditionally, March was the month that most reliably saw those conditions and that is why it is known as the peak of sugaring, with festivals and open houses always scheduled to celebrate.  In the past decade, however, climate change has upended the usual weather patterns and there is no such thing as typical. Some years have seen the biggest runs in February, with the whole month of March frozen solid. Others have seen the bulk of runs in April. The best we can do to prepare is be ready at the end of January and then wait and see.

When the sap starts to run, it is a race to capture every last drop.  A typical run might be on a day when temps were just below 32 that night and then rise to a balmy 38 by the time the sun hits the mountain. The trees might take a few hours to feel the warmth but by late morning, it will start gushing into the sugarhouse. It might seem like all we need to do at this point is boil up the sap but the work in the woods has just begun. 

Collecting Maple Sap
Valves, seen here, help isolate main lines from the conductor so the crew can check to see which lines have the leaks.


The entire tubing network is on a vacuum system which basically means when the sap comes out of the tap, it gets assisted through the network by a large machine that pulls it toward the sugarhouse. The vacuum is only strong if it is a closed system and that is where things get challenging with the 600 miles of tubing in a natural forest. The tubing is constantly being damaged by falling branches, weather and animals. Squirrels, in particular can be devilish by chewing the tubing to get to the sweet sap. In one section, one year, we found that they chewed off all the taps and stored them in a tree hole. Since they could not possibly have found them tasty, we decided they were just a bunch of pranksters.


The Steps of Maple Syrup Production
When there’s a leak in the tubing, sometimes you need to listen for air hissing through the lateral lines.


Because we usually only have about six weeks worth of sap runs to make a whole year’s worth of syrup, keeping the vacuum strong and capturing every drop is critical. When it starts to run, we can tell from gauges in the sugarhouse where the vacuum is low. The woods crew head out to that section to walk the lines and find the problems. Keep in mind that one section might consist of 12,000 taps. More gauges on each line help narrow it down but usually the entire area will be walked, looking, and more likely, listening for holes. When you get near them, a hissing sound will usually give them away. Sometimes a tap fell out or was missed. Sometimes there is damage the size of a pinprick in the middle of the line. Each hole that is plugged improves the vacuum and consequently the yield of sap.

Repairs in the Woods
There are endless repairs in the woods during this portion of the season


Walking the lines is arduous work because there is likely still snow to slow you down and sometimes you can walk an area multiple times before you find where the problems lie. We also have spring storms that can take an area of beautifully tight vacuum and leave it with bad damage from fallen trees or branches. In that case, the crew goes back up to repair lines and reestablish the system. The woods work is never done until the season ends when we pull the taps. But that is for a later blog.





Do the woods crew stay out there all day?
Usually.  It can take 45 minutes to gear up and take the vehicles up the mountain to a starting point. Unless the weather is abysmal or there is a reason to return to the sugarhouse to fix gear, they will be out there all day because the turn around takes too much time. Every day is a snow picnic for lunch.


What exactly do you mean when you say ‘tubing network’?
Basically you have small lines that lead to bigger lines. You start with the tap in the tree which leads to a drop, drop to lateral, lateral to mainline, mainline to conductor, conductor to sugarhouse. (Sounds like a sugarmaker’s nursery rhyme.) You can never get lost in the 1,000 acres of sugarbush so long as you can find the biggest line – the conductor – which will always lead you back to the sugarhouse.


Aren’t there ways to check vacuum remotely?
Yes, there are. We installed a very sophisticated system to help us narrow the search for problems several years ago. Unfortunately it relies on good cell service which our region is not known for. It is now being uninstalled.


If it stays warm, does the sap keep running?
If the temperature remains above 32, the sap will run hard for two to three days before it slows down, after which it needs a “recharge”. This is why the cycle of fluctuating above and below freezing is so important to keep it going. March and April are usually the best months for these conditions but towards the middle of April we start to see temps get above 32 and stay there. Without another freeze, the season is over.


Can you drink sap?
As long as it is fresh from the tree, absolutely. It consists of 1-2% sugar, minerals and water that has been sucked up from the ground by the tree roots and tastes like faintly sweet water. Some beverage companies have tried to use it as a natural drink or soda. In South Korea it is an important part of a spring ritual known as gorosoe. According to Smithsonian Magazine, “Gorosoe translates to “tree good for the bones,” but many Koreans believe its sap is good for all kinds of ailments, including high blood pressure, diabetes and hangovers. They gather for sap-sucking picnics or sit in heated rooms, playing cards and eating salty snacks like dried fish to work up a good thirst.”


When are you going to talk about the making maple syrup part?
In the next blog.
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