So we have some sap that we are wanting to take down to syrup. I write taking down because the normal process is to boil the sap down to syrup. But having a knowledge of practices formerly used by the Native Peoples of North America, I know that they threw the ice off of their sap to reduce down the water content. It seems that the Whites that were busy taking their land neglected to learn the practical survival stuff from them.
So, having only this for a knowledge, and not having any detailed instruction, I am pretty much on my own on this, this year. In the past I tapped trees, but I had a trusty wood stove to reduce the sap to syrup. That is not to say that I boiled the sap thus reducing the water. Rather, by sitting pans on the wood stove I reduced the water (while heating the house) turning the sap to syrup.
I spoke to a long time tree tapper to ask his opinion of reducing sap by freezing and he told me that it doesn’t work because sap freezes. In my experiments I discovered that that is correct, but only after the water has frozen first. That is why it has to be controlled freezing. You don’t want to take off more than a quarter of the water as ice at a time. His other evidence that the practice doesn’t work was that when you take the ice off and taste it you will notice sweetness on the ice. So I rinsed the ice off and then tasted the ice and it had the taste of non chlorinated water. To double check on this I kept the ice in a pail and let all of it thaw, during a warm day, and it confirmed that in fact it was not sweet. This proved that the process of taking ice off works, at that point the process had to be refined.
I add that I am not adding this information to criticize the tree tapper, only to expose you to the technique of experimenting, so you will be able to do your own experiments. Where the tree tapper failed in his assessment was that he didn’t rinse the ice off, therefore what he was tasting was the more concentrated sap that was on the surface of the ice when he licked it. I am sure what I instruct here is incomplete, inasmuch as it is only the first year of experimentation. The basics are here and are already valuable to save money and avoid pollution by this technique.
Here is a picture of my experiment of reducing the sap by freezing. I have 8 cake pans, but any wide container will do, that is so you have a broader surface area to freeze. I experimented with depths of sap put into the cake pans to discover how best amount of sap to add to the cake pans, to get the best amount of freezing. If you think about it, if you have a pail that is a 5 gallon pail there is so much more liquid that has to get to the point of freezing, therefore perhaps the top inch will freeze and the remainder remain sap. However, if I put the sap into pans, pots, there is only a small amount of sap in each, I will get upwards of a half inch of ice of each one. The smaller amount of sap has less heat to displace to get down to freezing point. And I discovered that what I do want to get is about 2 and a half cm of ice off each tray. I added about 7 cms of water to each pan so I took off not quite a third of the liquid off as ice each deicing. I appologize for my lack of understanding Metric, I actually went by the old Imperial standard of putting a little better than an inch of water in each tray and I aimed to take about one third as ice.
As I did this each subsequent deicing the amber colour of the liquid became darker, or deeper as you will. This further confirmed that it was only water that was being reduced and not the sugar portion of the sap.
So, with the criteria of taking one third of the water away, I found three variables. 1. of course the amount of liquid put in the pan in the first place.
2. was the temperature of the night, and
3. was how I could modify the effects of the temperature on the pan of sap during the night.
How I could modify the the temperature was effected by the length of time I left the sap out, and secondarily, and more importantly, whether or not I covered the sap, and with what. I will explain what I mean in a moment. You have to first understand that a minus 4 to minus 5 degree Celcius night is best to freeze sap and get the half inch of ice. Minus 8 Celcius was too cold and in the morning the sap would be frozen to the bottom. With this you know that the sugary portion of the sap froze. When this happened I brought the trays in and let them thaw to the point that the bottom portion of the sap thawed. I would not recommend doing it all the time, for reasons that are too difficult to explain. What I did do was to further experiment to control the freezing better. On a minus 8 degree night I would add more liquid to the tray, therefore take it longer to get to the freezing point, I would cover the trays with those aluminum oven bottom protectors, and if I couldn’t control the length of time in the trays, having to go off to work for example, and thus not be able to check on the trays, you can further cover the aluminum protectors with a towel. The idea was to slow the loss of heat from the trays.
On a night that was minus 2 degrees I left the covers off the trays and left the sap in the trays longer. I did the freezing outside, so some times it was windy and there was a risk of tree twigs getting into the sap, therefore where you freeze is important.
The Process of Deicing
I experimented with different ways of taking ice off the tops of the pans, and then I came to the conclusion that it was best to eliminate the sap from the pan instead; to eliminate the ice I had to bring the trays in and let the ice thaw somewhat so the ice would separate from the sides of the pan, in order to be lifted. This not only took time to the process, but later I found another reason for leaving the ice intact in the pan. If you think about it as you lift the ice up on the one end the other end dips under the sap, thus the more concentrated sap coats not only the bottom of the ice, but now you have just coated the top of the ice with the sap. This might not be too much an issue in the first or the second deicing, but each deicing the sap gets more and more concentrated and sweeter. Each time you get the top of the ice wet with concentrated sap you are throwing that much more concentrated sap away. Now, that might not be a problem if you have lots of trees and lots of sap, but for the typical urban tapper, you already have a limited number of trees to tap, so you can’t afford to lose sap to a more inefficient method.
Here is the ice that was taken off of the trays. It equates to about one third of the original pail of sap.
Here is how it looks pouring off the deiced sap.
Below is the raw sap from the tree.
This is the sap after the 3rd deicing.
Below is after the 7th deicing.
You have to remember that it takes 40 to 50 gallons of sap to get 1 gallon of syrup. That depends on the sugar content of your individual tress.
After doing my experimenting, I have come to the conclusion that l will not deice more than 5 times. The reason for that is because at the point the sap is getting very sweet and some of that sweetened sap is lost as a layer of liquid on the bottom of the ice; if you remember that is why I began to pour off the sap without trying to lift the ice off. When lifting the ice off the ice would go under the sap as I lifted, thus the top part of the ice had a layer of thicker sap on it, and then I would end up losing it when I threw the ice away.
So unless you have lots of trees from which you can get lots of sap, this 5 deice stage is where I began using heat to evaporate the water from the sap.
As you can see 2 trays of sap on left on the gas stove to let the water to evaporate. Below is the syrup that was made by evaporating water.
This was the first of the syrup made and at the point of me writing this there is one full container of syrup and another half in another container. We also have another 3 pails full of sap at the time that the trees have stopped dripping sap.
This year there will be sufficient a amount of sap to worry about keeping some for a long period of time, therefore I have to learn about the boiling. The sap that is reduced doesn’t have the same colour that store bought sap has, but none the less, it is swwweeeetttt. Now I have to learn if I have to pasteurize the syrup to keep it from going bad. The other alternative would be to keep the syrup in the freezer, in small containers so I can take out a small container of syrup as I need it. Remember that I can refrigerate it so the container doesn’t have to be that small. The other point is that I have to ask around to discover the purpose of pasteurizing anyways. Will it keep longer by pasteurizing? This is my experiment, so I am not yet finished my article; keep posted for the answers.