This is the end of a successful sap flow and syrup making season in my front yard. I harvested 24 1/2 gallons of sap and reduced it to about 3 quarts of syrup. Real, sweet, sugary, smooth, flavorful maple syrup. It took 4 days and 2 nights to cook it down. I split the syrup and did 2 days and 1 night twice. And with lots of patience and some research and just a little dumb luck it turned out great.
My method for reducing it was to put an enamel canning pot on the large electric heating element of my Brinkman meat smoker in my garage, in the middle of the concrete floor with the overhead door cracked open about 4 inches.
REMOVING 96% OF THE MASS OF THE SAP, WHICH IS WATER, SHOULD BE DONE OUTSIDE TO AVOID WATER DAMAGE TO THE INSIDE OF YOUR HOME.
The smoker element heats the whole bottom of the pot and does so at a top temp of 205 or so. It is especially handy because I didn’t have to worry about running out of fuel. I split the total sap into 2 parts just in case I botched it somehow I did not have a total loss. So as it steamed down all of day 1 I kept adding sap. As I went to bed around midnight I topped it off to within an inch of the rim and went to bed. My lovely wife wakes up early so when she got up around 6 in the morning she checked on it and topped it off again.
When everyone was up and the kids went off to school I kicked it into high gear by placing the liquid in the canning pot on a turkey frying propane cooker.
This is important to note: If you bring the sap to a boil then, for whatever reason, reduce the sap temp below 190 degrees F the finished product will have a haze that settles to the bottom. It is perfectly fine other than the appearance.
That said, I topped it off again and brought it all up to a pleasant boil. As I added in the remaining few containers of sap I did it slowly to maintain the boil. As it reduced to a point I could put it in a smaller pot I did that quickly (safety first) to keep as much heat as possible.
Now I started to monitor the temperature. Lets discuss that for a moment. It is said that water boils around 212 deg F depending on altitude and atmospheric conditions. It is also said that you technically have “syrup” when the sap will boil at 7 degrees above boiling. Roughly 219 F. So you can use the SWAG method (Scientific Wild Ass Guess) and just boil it until it will rise to 219 F. You can do better though by boiling water at this stage and getting an accurate reading on your suitable for the job thermometer and adding 7 degrees for your specific altitude and that days weather. I have done both and still my syrup came out thinner (after completely cooling) than I thought it should. Now back to the story.
I kept an eye on the temp and as it approached 214 F. I went inside and turned on my gas stove burner on as high as it would go. I went back to the garage and with oven mitts on I carefully carried the pot in and put it on the burner and got it boiling again. The time from stove to stove was about 15 seconds.
Now for the final work. I know that that day the digital thermometer I was using read a pot of boiling water at 208 F. I know that the syrup I made that was brought up to 219 (I went right past 215) was still thinner than what I thought it should be so this is what I did on my last batch. At this point I recommend the project gets your undivided attention. A helper is indispensable. I boiled vigorously until I got a reading of about 219 F then I put it on as low a heat as I could and keep it boiling. I brought it up to 221 F. At that point it was bubbling so much that the bubbles were slowly filling the pot. I then killed the flame and carefully poured the syrup into the canning jars I had prepared while doing this final boil. I put the lids on in accordance with normal canning procedures and let them be until the next morning. This is my result.
This is most of the 3 quarts I got from the 24 1/2 gallons of sap I started with.