Has been the call across Cape Breton the past few weeks and we decided to give it a try this year- because Nova Scotia winters are long and the trees seem to be the only living things that are showing any signs of spring so far. I wanted to find a reason to be outside and the teacher inside of me thought that this would make a great lesson on the interconnection of science, traditional knowledge and the economy right in our own backyard. It also become an excellent problem based learning opportunity for the entire family, with aspects of technology, chemistry and physics.
It all began with the discovery that the trees in our yard were all Sugar Maples. I learned that in Nova Scotia a lot of older homes are surrounded by Sugar Maples, because not only does the tree look nice and shelter the house from the elements, but traditionally many people made their own Maple Syrup. How do you know your if your tree is a sugar maple? Most people can identify a maple as a maple and to be fair all maples will give some kind of sap, just not as sweet as the sugar maple. Sugar Maples are identified basically by their distinctive bark and leaf shape it only took a minute to figure it out once I read this: http://garden.lovetoknow.com/wiki/Maple_Tree_Identification
The second step was to figure out if the sap was running and how to tap it. The Mi’kmaq refer to March Si’ko’ku which directly translates to “Maple Sugar Time” so that gives an approximate start time but how do you really know? One clue is the weather- warm days and freezing nights cause the sap to start flowing-there is an interesting biological lesson in there related to the pumping action of tree roots- and osmotic pressure but basically it was a watching game. When we had consecutive days of above 0C and below 0C nights we tapped the first tree to see what came out. When we started getting a steady flow we tapped the other trees.
We purchased all the tapping equipment for under $20 at the local hardware store. The equipment consisted of tree spouts and clear tubing. We used all manner of things to collect the sap, including cleaned milk jugs and kitchen pots. We quickly learned during peak running- milk jugs were too small. So we had to increase efficiency so as not to waste any sap, which when we started felt like magical drops of gold in a bucket. You need to be careful about where and how many taps are on a tree to ensure the health of your tree. Here is a quick reference: http://www.motherearthnews.com/diy/tapping-maple-trees-zbcz1502
The tricky part of the project began with sap to syrup process. We learned that the ratio of sap to syrup is 40:1, so that is a lot of liquid to reduce. This is where experiments in technology, chemistry and physics really kicked into high gear. Any of the problem solving we had done around collecting sap more effectively dulled in comparison to this new challenge. First we built an outdoor wood stove using an old metal barrel because boiling off that amount of water in the house would have created far too much humidity inside. After we fired through half our woodpile we got a little smarter- adjusting the fire height, pot size and insulation of pot to reduce heat loss. This involved conversations about surface area and heat transfer that involved many friends and family as we stood around the fire in the evenings. We also learned from Mi’kmaw tradition that if you pour out your Maple sap in large shallow troughs mother nature will do much of the work for you overnight. The water will freeze and rise to the top of the trough and you can lift the ice off in the morning leaving a more concentrated syrup underneath. We also learned that Maple water doesn’t taste half bad, and according to the Mi’kmaq is good for health. This was great news because our capacity to collect far surpassed our capacity to reduce the sap. After 3-4 days of intense work, we had produced about 20 mls of syrup. So how are local syrup producers able to make syrup that doesn’t cost a million dollars? We certainly felt the time an effort we put into our product made the syrup we bought (and previous found expensive) look like a bargain in comparison. Apparently the secret is osmotic pressure - commercial syrup produces reduce the sap using reverse osmosis. So next year we are trying that. It seems that good old osmotic pressure is the secret behind all things maple Syrup.
Lessons for kids and adults: