40:1 is a pretty good average, although it varies some with the sugar content of the sap.....which also varies according to time of year, and the variety of maple you have tapped. 2.5-3% sugar content is considered great, and some producers will check this with a refractometer. The higher the sugar content, the less time spent boiling.

I just tap the trees and boil...I have plenty of firewood for fuel!

"Forget pounds and ounces, I'm figuring displacement!"

If we accept that: MBG(+)FGSF(=)HBG(F1)
And we surmise that: BG(>)HBG(F1) while GSF(<)HBG(F1)
Would it hold true that: HBG(F1)(+)AM500(x)q.d.(=)1.5lbGRWT?
PB answer: It depends.