Need help operating my evaporator pan

[FordHeritageFarm]

This is my first year with an evaporator pan with 4 "channels". How do I draw off the last of the syrup without scorching pan on heat? Feeling dumb, but I need to ask.

[MapleME]

You need to leave enough syrup
in the pan until it cools off. Once the pan is cool, pull it all of and finish however you plan on it. If you pull it off hot, you will burn and ruin your pans.

[FordHeritageFarm]

What if I have about 300 gallons of sap. Shouldn't I be able to draw off eventually while the pan is drip feeding on the other side?

[sapbrush]

yes that is what i do i boil and boil and boil till i know i have syrup in the pan you can tell by the color set a thrmometer near the side you will draw off on when it reaches 218 degress start drawing off syrup, when it drops below 218 shut the valve and keep boiling till it reads 218 again then draw off more and so on. hope this helps jim

[Flat47]

What if I have about 300 gallons of sap. Shouldn't I be able to draw off eventually while the pan is drip feeding on the other side?

Let's back up a bit. If I read you right, you've got a flat pan, with dividers, and a drawoff valve in one corner - right?

If so, constantly adding fresh sap to the side opposite the drawoff will eventually create a sugar gradiant in the pan, just like you asked in the quote above. You will then have fresh sap at your inlet, and (after hours of boiling) syrup at your drawoff. At this point, continue adding fresh sap and drawoff the syrup at the same time (watch to keep the sap depth adequate in the pan). Watch a thermometer as you drawoff. When the temp drops a couple (2 or 3) degrees, stop drawing off. Repeat the process.

[FordHeritageFarm]

Thanks folks the info is helpful and reassuring. So is just letting the fire die out when the sap runs out the suggested procedure at the end? I would say that would leave me with about 2 gallons of sap/syrup in pan.

[wnybassman]

Thanks folks the info is helpful and reassuring. So is just letting the fire die out when the sap runs out the suggested procedure at the end? I would say that would leave me with about 2 gallons of sap/syrup in pan.

I'm new at the continuous flow thing too, but I think you want to start letting the fire die out a little before you run out of sap because of the residual heat and continued evaporation. Don't know how big your pans are, but leaving 2 gallons in there is not very much. Yesterday I left my 2x4 pan with 2 inches and that equates to almost 10 gallons exactly. I'm sure that 2 inches simmered down a little after I left it, but I also left it with the fire dead and coals shoveled out, it was still steaming good though. I pushed 70 gallons through it yesterday and still no where near syrup near the draw-off. I am hoping the next 60 or 70 gallons will get it there, but I don't know yet.

Here is a good site for converting volumes: http://www.thecalculatorsite.com/conversions/liquidvolume.php

[jmayerl]

When shutting down for the night you should draw off some near syrup and add it back near the draw off when you start up again, that will start your gradient again.

[Brent]

This is my first year with an evaporator pan with 4 "channels". How do I draw off the last of the syrup without scorching pan on heat? Feeling dumb, but I need to ask.

First go to "Forum Actions" and update your signature to tell us more about your operation. It will help other readers understand where you're at and the answers you get will be better suited to what you have in equipment and operation size.

Normally you would watch your supply of sap and depending on the size of your pans, stop adding firewood so that the pans stop boiling before you run out of sap. As soon as the boil stops, stop adding sap. The remaining raw sap should be allowed to chill down ASAP, which might mean running it back outside ovenight. Quite a bit more water will evaporate out of the pan as it cools down. You could lose half of the depth overnight if you have a single flan pan rig. The next day, check the depth, start your fire and start adding raw sap again, slowly building up the depth to your normal boil depth and the pans start to boil again. This will help maintain the gradient of more near syrup closest to your draw off valve. Again depending on your configuration, you may see draw offs starting up again in 20-30 minutes or it may take 3 - 4 hours before draws start.

The first day on a small flat pan set will largely do little more that set up the gradient. It can take 8 - 10 hours to get your first draw off. A small flat pan set will only boil 8 gallons an hour or so, which means theoretically you need to boil for 5 hours to get it down to 1 gallon of syrup. That's theoretical ... in reality, you're adding raw sap and continuously diluting, and there is considerable mixing even in a divided pan so you can see that the first draw takes forever and a day.... and thus the importance of maintaining the gradient for starting up the next day. When we used a Leader Half Pind (2' x 3' flat pan) I learned that hanging a stainless panel over the ports in the channels really helped stop the concentration migrating and balancing all around the pan overnight, and maintain the gradient a for a better start the next day.

Hope this helps ...