Freezing nights and warmer days in the 40s are ideal for maple sap flow. As I understand it, the wider the day/night temperature gradient, the more pressure is built up in sap channels and therefore the more sap will be expelled if tapped. In more wintery parts of North America, these temperatures typically occur in early spring, but in Oregon, we only get semi-consistent nighttime freezing in the middle of winter. Last year, we tapped right at the tail end of a cold snap in late January, so the flow started off good, but then things warmed up and basically never froze again, so the sap run (at least our collection of it) was short lived.
We knew we wanted to put in our taps earlier this year, and we had discussed January 1 even though much of what I’ve read about maple syrup production suggests focusing more on the climate conditions and the signs of spring coming along instead of calendar dates when deciding when to tap. We didn’t actually get our act together until Monday, January 6, again right at the end of a cold spell perfect for pressurizing maple trees.
Last year, we originally tapped two trees along our driveway and one tree about a half mile down the hill by our pond. After a few days, it became clear that although one of the trees by the driveway was a moderate producer of sap, the other one was pretty pitiful, so we pulled that spile and plugged it into another maple, which ended up being a little more productive but not much. The tree by the pond, however, was, at times, dripping in a nearly constant stream, and it ended up yielding at least two or three times as much as the other three trees combined.
With that in mind, we headed straight for the pond on the afternoon that we decided to put our spiles in this year. Before rigging the tree that we knew would be good, Henry drilled two other maples nearby to see if they had any potential. One was essentially dry, and the other wasn’t doing a whole lot. According to this publication from University of Maine, trees over 25″ in diameter can handle up to three taps, so we decided to put all our eggs in one maple tree basket.
We know from our own limited experience that individual bigleaf maple trees in Oregon can be highly variable in their production of sap. This fact was previously recognized in this 1972 Forest Service study conducted in Benton County, OR where we live. The thing that has really surprised me this year is the variability of output among taps ON THE SAME TREE. Of the three that we have in our high-output tree, one is pretty weak and sometimes dry, one has significant flow, and one (lowest in height) is dripping away, outpacing the other two by 200-300%. I must stress that this is a sample size of three taps on one tree, so I can’t make any generalizations about bigleaf maples on the whole, but it seemed pretty weird to me.
I have observed (maybe you have, too) that there seems to be a 24ish-hour lag between a change in weather conditions and a change in sap flow. When the weather turned warmer the middle of the month, our tree was still producing pretty well even though it hadn’t frozen the night before, but after two thawed days, the flow waned considerable. Conversely, it dipped back into freezing temperatures again after a week of warmer weather, but the morning after the first freeze, our sap buckets were still nearly empty. There were days when I was convinced that the buckets would be full, and they turned out to be dry and other sap collecting trips where I was pleasantly surprised by the output. This single best day was probably January 7, the day after we put the spiles in, although there was another uptick around January 21-22.
One of the things I vowed to do better this year is record keeping. At the end of our run last year, I had no idea how much sap we collected and only a fuzzy guess as to how much syrup we produced because we had already eaten a good deal of it before I thought to measure. This time around, I’ve been diligently logging approximate number of gallons of sap collected each day (or two days when flow is slow) as well as the amount of finished syrup produced. So far, I’ve collected approximately 15 gallons of sap and produced about 5 cups of syrup.
My sap collecting schedule has been a little erratic, but so far, I haven’t let any buckets run over. I’ve been making the trek down to the pond almost every day, but a few times, I left things alone for two days when I knew because of the weather that not much would be dripping. During peak flow last year, we had to collect sap twice a day to prevent any spillage.
Each time I collect sap, I bring it up to the house and pour it through a strainer (to remove bits of moss and drowned fruit flies) into a pot on the stove right away. I haven’t tried storing sap to accumulate a larger quantity because it can go bad unless it’s refrigerated or kept cold in a snowbank. We’re using the wood stove in our house for most of the boiling. Last year, lots of folks suggested that we should boil outside to avoid various unpleasantries (sticky condensation, peeling wallpaper, and such), but we’re doing it indoors again because it wasn’t so bad last year, and we’re working with what we’ve got.
If we keep a not-necessarily-roaring fire going, I can boil one or two gallons of sap into syrup in less than 24 hours. More than two gallons takes a little longer, especially if we’re not home the whole time to keep stoking up the fire. The problem with doing these kinds of less-than-two-gallon micro batches of sap is that it’s really hard to tell when they’re done. Two gallons of sap will only yield less than a cup of syrup, and with a tiny amount like that, it’s difficult to check the temperature accurately.
From what I’ve read, one can know when the sugars in syrup are sufficiently concentrated without using a hydrometer by allowing the liquid to reach 7° above the boiling point of water. At 800 feet elevation, the boiling point of water for us is between 210° and 211°, making the syrup point about 218°. About a year ago, I bought a Thermapen instant read thermometer (the one they’re always raving about on America’s Test Kitchen) for cheesemaking, but it works well for syrup, too, although you’ve gotta have at least an inch of liquid in the pot to get a decent reading. The problem for me is that even with a fancy thermometer, I’ve still over or under cooked nearly every batch of syrup so far. I have a few jars of watery syrup that I’ve marked to eat first instead of hassling with boiling it more, and I have one jar of nearly solid maple sugar that I made on accident. Another time, I overboiled the sap until it turned into the most amazing maple caramel of sorts. It was delicious but also unintentional. I boiled one of the smallest batches until it was all stuck to the bottom of the pan and somewhat burned, and then I tried to salvage it by adding more water and reboiling it to syrup consistency (not recommended).
Last year, Abby (among others) left some insightful comments including one that suggested syrup season was over when the crocuses bloom, and I saw my first spring crocus blooming a couple days ago. Maybe this is the end for this year. Was it worth it? For me, yes, but for someone who has less free time or no wood stove or less productive trees, it might not be. The abstract in the 1972 study about making bigleaf maple syrup in Oregon ends with, “Sirup production appears quite feasible as a hobby. The possibility of commercial production should not be ruled out as additional local experience is gained.” I think those are pretty appropriate words, and I’ll be working on gaining that local experience for at least a few more years.