Yeah my uncle makes maple syrup and it can take 40 gallons or so to one gallon syrup...
Not to hijack but the last time I saw him he told me he always has an interesting thing he calls "almost syrup" left over when he finishes making a batch, it's a syrup that's maybe 60-70 percent as concentrated as maple syrup. Apparently he has a lot of this, he gave me a big jar for experiments and told me I could always get more.
I'm thinking of trying using about a quart of it in a brown ale batch, see if it gives a hint of maple flavor or not. I tried making beer with maple sap instead of water before, and while it was a good beer I'm not sure it had a definable maple character.