well here is an idea with the sap.. check the brix (or sg) at the start and as you reduce it on the stove check it periodically (hydrometers have a temperature they like to be accurate so do NOT check the hot liquid, pull some out and put it in a cool bath.. eg using a ladle pull out 16oz into a metal bowl and place into the sink with a small amount of cold water, enough that the bowl does not float. )
Once you get to the brix (or SG) desired, remove from heat and cool and ferment as normal.
I would suggest adding some acid blend but that personal choice.
I started a 1G batch of Maple wine on 3/8/17. Boiled down 12 G sap down to almost 1G, and dumped it onto 1/2lb chopped golden raisins. SG at that point was 1.130 which was a bit higher than I wanted, so I diluted with 42 oz. boiled-then-cooled water to get an OG of 1.102. Added 1 tsp of bread yeast, 1/2 tsp wyeast nutrient, 1/2 tsp LD Carlson nutrient all boiled together for nutrient purposes, plus 2 tsp. acid blend, and 1 oz. oak cubes that had been soaking in rum(for tannins). Also added 1tsp of maple extract and 1/2 tsp. vanilla extract. Pitched 1 pkt. of Red Star Cote des Blanc. After 1 week I racked it off the sediment into a 1G glass carboy. This weekend I plan to check an SG and rack it off the lees for the 1st time. She's pretty cloudy, so I moved it out to my cold garage for a couple days ahead of time. 1st time doing a maple wine, so don't have any expectations on how it will turn out.
Racked her today. SG=0.096. Slightly sweet, a little tart, and a bit of maple flavor, which I believe is coming from the extract. I anticipate at this rate of clearing that I may be bottling it in June. And will probably not even touch it for a year once bottled.