When it comes to making maple syrup, temperature is king. First, there are the temperature fluctuations over the winter, which determine which kind of snow you have to walk through to get to the trees and tap them. This winter got most of its snow in February, without any freeze/thaws to harden it up and create a crust, so I faced two feet of pure powder to wade through – snowshoes actually made it harder to walk. Each tree I managed to slog uphill through this knee-deep fluff to was a minor victory – 2750 such victories over a two week period left me with sore quads, but feeling pretty fit.
Click here for a video of me wading through the snow.
Then of course there is the all-important above-zero temperatures in the day, followed by below-zero temps at night that drive the sap flow in sugar maples. That process started a few days before our first boil on March 12. Usually the weather allows us to ease into the rhythm of making syrup, with maybe a couple days of thawing, followed by a return to frosty winter for a few days, giving us a chance to rest. But not this year – spring hit hard and rarely looked back. The temperatures quickly climbed into the teens and stayed there for a worryingly long time. This was concerning to us because too high temperatures are the enemy of maple sugaring – they cause the sap to spoil and the tapholes to close up. We breathed a sigh of relief when the temperature dipped back down to more seasonal levels after that initial week.
What these high temperatures did do was to create a lot of amber and dark syrup. Normally, we make a lot of golden syrup in the first half of the season, and then as outside temperatures begin to climb, the syrup colour changes to amber and then dark. But this year the syrup started off amber (we’ve never seen that before), then it dipped back to golden for a few days, then back to amber for much of the season, before finishing with a good amount of dark. The reason for this comes down to the interplay between microorganisms in the sap, which are more active at higher temperatures, and the heat from the cooking process. I read an article recently that described maple syrup as a fermented product, and this is how I like to think about it now. The fermentation period is short – maybe only a day or two that the bacteria have to subtly transform the sap on its journey from the tree to their bubbling annihilation in the evaporator – but the effect they have on taste is profound. Most people prefer the taste of syrup that has been made from sap that’s undergone a bit of bacteriological transformation. So, amber and dark lovers, rejoice! Our bottling shed is stacked high with bottles of these richer tasting syrups.
Another important temperature is the boiling temperature of syrup: 7 degrees Fahrenheit above the boiling point of water, which usually means 219 (it varies a bit with atmospheric pressure). A gauge on the side of our evaporator keeps tabs on this variable, and when it hits 7, it’s time to open the tap and let the finished syrup flow out.
The final temperature of note in maple syrup’s voyage from tree to bottle is the bottling temperature. It’s recommended that syrup be bottled over 180 degrees Fahrenheit to avoid any mold forming on the surface of the syrup. Go too high, though, and minerals in the syrup solidify and the finished product looks cloudy. Trial and error has taught us that bottling between 188 and 192 offers the best defense against both mold and cloudiness.
Every season has it’s peak – that time when you’re boiling flat out, wondering if you can keep up with the deluge of sap pouring in. This year, that day came on March 30. We measured 8 gallons of sap per minute streaming into our collection tanks. The membrane on our reverse osmosis – the unit that separates out three-quarters of the water in the sap before boiling – is getting older and can only process 6 gallons per minute. So we had 2 gallons of sap more than we could handle coming in each minute. With our tanks getting close to overflowing, our solution was to increase the flow through the osmosis by decreasing how much it concentrated the sugar in the sap. This meant more boiling time, but we had bought our evaporator before we had an osmosis unit, so it is big enough to do more if needed. We boiled so hard that our chimney is now stained blue from the heat, and by midnight we had set a new record for us of nearly 400 litres of syrup bottled or put in buckets in a day.
What we’ve heard through the maple grapevine (or sapline?) is that our experience that day was shared by many; some of the old-timers who have been doing this for 40 years have apparently never seen sap flow like that before. March 30, 2021, was a day we won’t soon forget! But not a drop of sap was wasted!
I wish I could say the same about the recurring experience of waking up to an overflowing sap tank, but unfortunately we lived this experience three times this season. We had a lot of nights that never froze, so even though we’d empty the tank before going to bed, we’d wake up to find it spilling out the sides once again the next morning. We plan to invest in some kind of automated electric pump to rectify this issue in time for next season.
We did our final boil during the unnaturally summer-like temperatures of April 9 – a full week earlier than we’d ever finished before. We produced nearly 3500 litres of syrup in the end – down from the 4000 last year, but still our third best result in the seven years we’ve been doing this now. And honestly, given how warm most of this four week season was, we felt happy to get that much. And on a personal note, I was happy to celebrate my first birthday (on April 13) in eight years not spent boiling sap (unfortunately COVID-19 prevented me from doing much else).
We’d like to give a big shout-out to our neighbours/workers who helped us get through another boiling season: Carolyne Douglas our bottler, who was a wonder of organization in the bottling shed and our first bottler who never had a single mop-worthy syrup spill event, and Shaun Glover, chief tap-puller and sanitizer of many years now. It’s been great to work with people who live so close they can smell from their homes the smoke from our wood-fired evaporator.