J empties his sap container into the collection bucket. We collected a total of 5 gallons of sap in a 24 hour period out of 13 spiles (although two of the homemade ones didn't produce a measurable amount of sap due to functional difficulties) placed in 6 trees. That's even accounting for spillage and waste (we probably lost another gallon that way).
Then it was time to boil the sap down to eliminate a good quantity of the water content -- we want to take the sap from about a 3% sugar concentration to about 65%, at which point it will be syrup. In order to do that, we've got to boil the sap until it reaches about 219 degrees F -- which takes a lot of heat over a long time, and produces a copious amount of steam. Making this a very good outdoor project!
Since we're working with a very crude evaporator (just a pot over an open flame), it would be difficult to manage the heat for the final production of the syrup, so what we did was to boil it down to a more concentrated sweet water, then I sent it home in quart jars with the individual families to finish off into syrup on their stove tops. This is actually how the colonists did it -- they would boil their sap in a central community cauldron, then the families would bring smaller amounts of the boiled down sap into their stoves to finish off into syrup (or take all the way down to sugar, which kept better than syrup and was used in baking and cooking for the rest of the year).
Here's our results from 5 gallons of sap -- about 5 quarts of concentrated sap, which then went on to produce about 2 1/2 cups of syrup total. So that's about 1/2 cup of syrup for each gallon of sap.
Since we've been sending the concentrated sap home with other families, we've not finished any syrup off ourselves yet. We boiled again on Friday for more families. And we'll finally boil the rest of what we collect for ourselves on Sunday, and finish it off either Sunday evening or Monday. I'm planning to "sugar off" some of what we produce as well and bring the resulting candy as a treat for the kids at our end-of-project pancake lunch next week.