We have a mini pro evaporator that has a finishing pan that is roughly the same size BUT it is a least 12" deep and has a float valve that let's sap in. It runs at about 3/4" deep, having sap much deeper than that I'm not sure you'd ever get to a gradient. As it is we run for at least 10 hours before we get close to what I would call a gradient. Even then, the pan area is so small that it's more of a continuous batch process where we draw off small amounts at around 30 min intervals.The depth of our pans is critical as by the time the syrup is ready for draw in third channel the sap in second channel is foaming up- sometimes exceeding the height of our 9" dividers.
2023 - 130 taps, 90L from 4,000L as of mid March
2021 - 84 taps, 50L from 2100L
2020 - 100 taps on buckets, 21L syrup from 2700L so far (FEB 26-Mar 13) and then the pandemic hit! End of our season!
2019 - 62 taps on buckets, 95L syrop from 3215L sap
2018 - 62 taps, collecting by hand, 90L syrop from 3200L sap
2017 - Lapierre Waterloo Small mini pro with 40 taps
2014 - 2016 40 taps making one or two batches on a 2x6 flat pan over an open arch as it would have been done in 1900