Annual routines, like making maple syrup, are dependent on weather conditions. 2025 has been a bit unpredictable in our corner of the woods. We’ve made a small amount of syrup, but it looks like it will be a poor year for us. Other areas may have better success. It all depends on weather.
The late winter/early spring flow of sap in trees is a hydraulic process. Nights below freezing create lower pressure (relative to atmospheric pressure) in the stem of the tree, pulling sap up into the stem. Days above freezing create a positive pressure that releases the sap to flow back down towards the roots. If you drill a hole into the stem, you can catch the downward flow of some of that sap. That is “tapping” a tree. It all depends on the freeze-thaw cycle. If it is too cold, the sap won’t flow. If it is too warm (not below freezing at night), the sap won’t flow. This year we have had both “too cold” and “too hot”, with a little bit of “just right” mixed in. We have collected some sap, but not consistently enough to host our demonstration days.
There are other weather factors that make a difference too, especially affecting when sap flow begins. Snow depth affects how deep the frost goes into the ground. Deep snow insulates the soil, so the frost doesn’t go as deep. This year we got our share of bitter cold, but not our share of snow, so the frost went fairly deep. And that affects the soil moisture available for the trees to pump out of the ground. When we had early warm temperatures (in January and early February), I didn’t tap, but I heard that those who did were disappointed in the result; the temperatures seemed right, but the sap wasn’t flowing. Even though the soil surface may get soft and mushy on warm days, the frost works its way out of the ground from the bottom up. That’s why you have perched puddles in the spring until the thawing works its way up to the surface. There are a lot of nuances to why sap runs better some days than others, and in some areas better than others. I think northern Wisconsin is having perfect conditions this week. Our southern neighbors (southern Iowa, Illinois, etc.) are probably done for the season already.
Interestingly, the process of sap movement occurs in all trees… not just maples. Syrup is also made from a few other species, like black walnut, birch, and sycamore. However, sugar content is lower and you’ll need a lot more sap to make a gallon of syrup. We collect sap from about 30 sugar maple trees out in our forest. Once we get the sap collected, there is quite the process to turn it into syrup. It drains into food-grade 5 gallon buckets. We carry buckets of sap back to the homestead in a UTV, as long as the trails aren’t too mushy. Our ratio of sap to syrup is around 40:1, meaning it takes 40 gallons of sap to make a gallon of maple syrup. We use a hobby-level reverse osmosis (RO) system to remove some of the water from the sap before we start boiling. The RO removes about ½ of the water, so we only need to boil off 19 gallons of water instead of 39 gallons to get a gallon of syrup.
The boiling process for making syrup is more than just removing water. The long process of boiling caramelizes the sugars in the sap, creating the distinctive flavors of maple syrup. We boil our sap over a hobby-level boiler from Smoky Lake. It is basically a wood stove fit with a special stainless-steel pan on the top that boils off about 4 gallons of water per hour. The boiling pan works best with about 4 gallons of liquid in it; we can go down to about 2 gallons before we are at risk of boiling dry and ruining the batch of syrup. It takes at least 50 gallons of sap to run the boiler to get anywhere near to syrup concentration.
Once we get the syrup down to the right concentration of sugar (66-68%), the hot syrup is poured through a special orlon filter that removes the “niter”. Niter is the minerals that were in the sap. Then the hot syrup is bottled into glass jars and sealed. Syrup with a sugar content of 66% or more will safely keep for years.
So far in 2025, we’ve completed one small batch of 1.25 gallons of syrup. Last year we reached 10 gallons of syrup. I’m hoping for at least a couple more gallons this year, but “weather” or not that will happen is yet to be seen! I don’t “sell” Iowisota syrup; it is available for our own use, for friends and family, and for Iowisota events throughout the year.
Speaking of events… We have a few on the calendar. We are currently figuring out how business insurance will work in 2025, so we aren’t widely promoting or adding new opportunities until we know all the details. But I am very excited about the ones we have on the schedule. Sam Thayer’s Spring Foraging workshop on May 3rd is already full. Dwight Zietlow’s Kordiall workshop on May 17th is ½ full. Sam Thayer is also leading a prairie-focused workshop on July 19th that is already half full. I expect these opportunities to fill up.