I ordered some dark amber maple syrup from a producer from Oneida, NY (http://daveandjoanssugarhouse.com/) that I met on the Forestry Forum and was reminiscing about visiting my grandfather up in Lowville when I was a kid and the good times spent stoking the fire at his friend's sugar shack. He told me times had changed just a bit:
"Ted,.... You’re welcome to come stoke a fire again for old times sake. Today however, we use vacuum to enable us to get more sap and to move it to a collection tank, then we reduce it using Reverse Osmosis to anywhere from 8% sugar up to about 14-15% sugar, all before it goes into the evaporator, thus cutting time and firewood to less than 20% of what it would have been. I have a 3x8 evaporator and with the concentrated sap feeding it, I can draw about 7 gal./hr. Far faster than the 5-6 qts I got before investing in the RO."