alaska birch syrup question

[jake1]

i live in alaska and am building a 2x6 arch, for birch syrup, ive been trying to maximize my gph by design, insulation, air, etc... my question is can you overboil birch sap, now i know it gets tedious when you get down to around 30-40% and i finish on a double boiler but what about when your running deep in pans, can you really rage the boil or do you have to keep it around 100c.can you burn syrup before its concentrated? just wondering because i dont want my arch to be too hot for birch. any ideas or info would really help, thanks
jake

[KenWP]

You can't over boil it untill it gets concentrated then it becomes a chore.For the first several hundred gallons it's just water. Has a nice red colour to it when you are starting out.

[BC Birch Tapper]

Jake,
When building your arch consider insulating it well as you are going to all this effort. I used an insulating board behind the firebricks & it works well. You can have boil overs if you go much above 100 deg C. You can keep the temps & fire raging, I "Log on" every 8-10 minutes, but if you go crazy you can have a boil over & then the clean up is not alot of fun. Using the defoamer agent to drop the foam or open the door to reduce the temp.
The temps are more critical as the syrup becomes more concentrated. The type of evaporator you have will make a difference in your draw off %. Our 2x6 raised flue we get between 20-30 % brix. You can't get more than that as the sugars concentrate you need to drop the fire down & your evaporation rate goes out the window.
I talked to a fellow from ontario who had a very wide evaporator 4 x 10 or something with a ceramic blanket who ran his depth at < 1 " in the pan & ran it on oil & he got a much higher sugar content at draw off. When he took the heat away the temp reduced very quickly. Ours retains the heat for several hours after we shut down.