A trick to reduce the ratio before boiling is removing the ice, as the sugars will tend to not freeze into the ice. On very cold mornings I have gotten it down to 20:1 or so. I'm sure some sugar is trapped in the ice, but not much.
I used 3-gallon plastic (surgical) bags on holders, which allows draining the remaining unfrozen sap into buckets, and then tossing out the ice. Usually a hole remains in the ice on the tree-side of the bag. It saves quite a bit of boiling in the right conditions!
I am missing it this spring, but I am over-booked with Scouts.
