Boiled down 44 gallons of sap today, with an evaporation rate around 6-7 gallons per hour. I was very pleased with that, especially on a homemade rig.
Steaming away.
Skimming off some foam.
What was left after the boil.....about 1/2" in the pan, which is cutting it close. Very easy to scorch when it gets that low. Nice carmel color, but it's not syrup yet...it needs a further reduction, which I will do over propane as it's easier to control the heat when things come down to the wire.
This is simply referred to as "sweet". As in: "I've got a half inch of sweet in the pan"