Boiling Out Pans
We've often been asked what we do during the off-season once the temperatures have warmed up and the sap has stopped flowing. One of the immediate tasks is to clean up from the season that just ended and prepare for next year. Although its not as much fun as tapping or boiling, its still an important job and we thought we'd tell you a little bit about how it all works.
The first job at the end of the season is to "boil out pans." This is the process by which we collect the final syrup of the season that is remaining in the evaporator.
Because our evaporator is a continuous flow style, we don't drain the evaporator at the end of each boiling session (in fact, the evaporator needs the sap in it to help keep it cool as the fire goes out and the evaporator temperatures drop, so we can't drain it or run it too low). However, there's actually quite a bit of sap in the evaporator pans that we don't want to lose. To get this sap, we close the valve connecting the front and back pans and then use a small pump to pump all of the sap in the back pan into a temporary holding tank. We then fill the back pan with water and put water in our head tanks (remember that the evaporator can't be heated when it is dry, so we have to keep a level of liquid in both pans, and the water just protects the back pan during the next steps. As a side benefit, the boiling water helps make the cleanup process later a little easier).
Once we have the sweet sap in a holding tank and water in the back pan, we start to boil the sap using only the front pan. This takes a while because now we're not boiling with a 5x14 evaporator- instead we have a 5x4 flat pan (with the back pan disconnected). As the sap in the front pan boils off, or when we draw off, we pump more sap into the front pan and continue to process this sap until we've used up all of the sap stored in the holding tank. Although it varies from year to year, we've found we can have as much as 60 gallons of syrup produced from this process.
The final stage of the process is tricky and usually takes at least two people who are paying attention. If we've done everything right, the fire is just about ready to go out as the sap level in the front pan drops. One person then watches the draw-off while the second uses a paddle to push the sap slowly out of each section in the front pan and then plugs the connection between the sections with a clean cloth. Water from the back pan can then be introduced into the now-empty section and we boil again for a while. In essence what we're doing is slowly reducing the size of the front pan and pushing the "almost-syrup" around until it is eventually all in the pan closest to the draw-off. When this sap has boiled long enough to become syrup we draw it off and introduce water into this final pan. If we've timed everything correctly, this is exactly the moment when the fire has died down and the water is just steaming a little (if there's too much fire we can remove some logs with tongs or just add extra water to boil as the fire cools). Although the syrup we produce this way still is generally acceptable, we package it in 40 gallon stainless steel drums to be sold to a bulk syrup buyer. There it will be used in processing to provide maple flavor in baked goods or other products. We reserve only the highest quality, best tasting maple products for canning and our direct-to-consumer sales.
Once this final syrup of the season is drawn off we can clean the evaporator. After letting it soak for a a few days (or even a week) we've had great success using a pressure washer to remove any residual sap, leaving the pan clean and ready to use next year.