Shutting down evaporator and preventing mixing of flue fluids

[M.MacKenzie]

What is the best way to shut down the evaporator and keep the syrup pan flue fluids from mixing back together as it cools? I working with a 3x3 Small Brothers pan with four flues with open port holes (triangular) between the flues at each other end. Thanks.

[gbeneke]

Chopper,
I have a 2x4 evaporator also and mixing is a problem. A raised flue evaporator allows you to prevent mixing.I try to push out as much sweet as I can and collect it for another day. If you are out of sap, I run water through my evaporator to get as much sweet as I can and than shut down. The next day, I drain off the water and start again. Hope this helps.

[Sugarmaker]

I dont think you can control the mix unless you have plugs between each partition, and between the front to rear pans. Yes raised flue will work, syrup cant flow back up hill.
Regards,
Chris

[Haynes Forest Products]

Sometimes keeping the different grades from mixing in a small pan isn't worth the trouble. Do you have a float that feeds it so its a contentious draw off style? Trying to make port covers and keep them tight to stop the mixing can be a PITA. Then as it cools and continues to evaporate you want the liquid to level off so you don't scorch the pan. Then at start up you have to be careful not to burn the pan at start up.

I say let it mix and at start up just be ready for the big long draw off.

[johnpma]

I stop firing and draw off the finish chamber of my flu pan and store it in a food grade container. I do it visually by color until all three flu chambers are the same color then I flood the pan and empty the pre heater. When I start up again I slowly add the near syrup that I drew off previously to the third chamber in the flu pan. It's has worked out quite well for me

[DrTimPerkins]

...then I flood the pan and empty the pre heater. When I start up again I slowly add the near syrup that I drew off previously to the third chamber in the flu pan. It's has worked out quite well for me

Not sure I entirely understand your process here, but if you flood the pan and pre-heater with sap, you should continue to run your evaporator for a short time...at least until the liquid boils again. This will kill any microbes in the sap and reduce the chances of spoilage in the pans between boils. Otherwise you run the risk of the sweet going ropey faster between boils. This can happen also with certain types of evaporators with floatboxes that aren't tight against the side of the pan, or that don't see much flow of hot liquid through them. To prevent spoilage in those systems, people will draw off hot liquid and pour it into the floatbox to kill any microbes before shutting down.

Most will plug (or shut off a valve) between the flue pan and the syrup pan to prevent mixing. Other than that, drawing off a bucket of near syrup at the end of a boil and saving it to add to the last partition before the next boil is standard procedure. Helps to develop the gradient faster.

[Kbrooks80]

I have a hybrid 2x5 pan from smoky lake. After I draw off my sweet and flood the pan, I put a piece of flat ss on the finish side of the hole between the two sections. This seams to keep my pan ready for the next boil.

[johnpma]

Not sure I entirely understand your process here, but if you flood the pan and pre-heater with sap, you should continue to run your evaporator for a short time...at least until the liquid boils again. This will kill any microbes in the sap and reduce the chances of spoilage in the pans between boils. Otherwise you run the risk of the sweet going ropey faster between boils. This can happen also with certain types of evaporators with floatboxes that aren't tight against the side of the pan, or that don't see much flow of hot liquid through them. To prevent spoilage in those systems, people will draw off hot liquid and pour it into the floatbox to kill any microbes before shutting down.

Most will plug (or shut off a valve) between the flue pan and the syrup pan to prevent mixing. Other than that, drawing off a bucket of near syrup at the end of a boil and saving it to add to the last partition before the next boil is standard procedure. Helps to develop the gradient faster.

Morning Dr. Tim, Thanks for the response. I do not flood the pre-heater but I do completely empty the pre-heater into the pan (about 2 gallons small hobby unit). The residual heat in the evaporator, the heat of the sap in the pan that was boiling and the warm sap from the pre-heater will continue to boil for a bit as the temp of the evaporator decreases. I basically take the near finish sap out so that it does not mix. I do this at the same time I stop firing but yes there is still a boil happening mainly from the residual heat in the firebox. Maybe I'm over-thinking my process by removing the near finish stuff and not letting it mix.

[blissville maples]

As Dr Tim said, draw off a portion of sweet after your last draw off the day. When you first fire up for the next boil add it back to syrup side.

[HHM-07]

I have a 2x4 with leader pans I put a valve between the front and back pans. Works good I clean the front an after each boil, makes for good light syrup...