Wort Chiller Preheater

I'm considering adding a wort chiller type preheater to my barrel evaporator. It would consist of a new support rack for a 3 gallon SS stock pot filled with water adjacent the stack (for heat) and a wort chiller (50' coil of 3/8" SS tubing). I figure the water in the pot, heated by the stack, would transfer heat to the cold sap flowing through the coil submerged in the pot of water. When I run out of sap, the water will prevent the remaining sap in the coil from burning. The coil end would discharge directly into the pan.

It seems that the preheater pan, located adjacent the stack is a very common preheater type and I've seen the coil around the stack idea (and read of it's disadvantages), but have not seen or read of this wort chiller approach. I've searched the forum for wort chiller without finding much.

Any comments regarding this would be appreciated.

I've actually been thinking if doing something similar. I have been toying around with the idea of doing a coil around the stack that just circulates into the stock pot and then a second coil in the stock pot that the sap flows through. That was there is never a risk of scorching the sap in the line.

I have 3/8" copper tubing wrapped around my stack it works pretty well. I wrapped the tubing in ceramic insulation and taped it all up in foil tape. My sap is heated to near boiling at a flow rate that keeps up with my evaporator, about 1quart a min.

I use one of the cheap surflo knock off pumps you can get on Amazon for 20 bucks to pump sap thru the heater. Using a pump keeps the coil under a little bit of pressure which eliminates the chance of your preheater getting vapor locked from steam. The pump pretty much eliminates the risk of sap scorching in the tube.

The pump also makes it very easy to purge the heater of sap at the end of the day and rinse it with clean water. That keeps everything clean for the next time you start up.

I don't think that you would get enough heat transferred from the stack to the stock pot to make much of a difference. Even if the pot was touching the stack there would be so little direct transfer area that your water might only be barely warm at the end of a long boil.

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Originally Posted by mol1jb

I don't think that you would get enough heat transferred from the stack to the stock pot to make much of a difference. Even if the pot was touching the stack there would be so little direct transfer area that your water might only be barely warm at the end of a long boil.

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I agree with this you really need to wrap tightly around the stack to get enough heat transfer to make it worth the effort.

I use my stainless steel wort chiller to heat the sap before it enters the pre-heater pan. It fits perfectly around 8" flue pipe and does warm the sap up quite a bit. At least I'm not introducing cold sap directly into my pre-heat pan. Not sure if this would work with 6" or 7' flue pipe as the wort chiller needs to be very close to the pipe to pick up sufficient heat. When I start to run out of sap I add 5 gallons of water to my mini head tank (beer bucket with spigot) and divert the wort chiller outlet flow away from the pre-heater pan into a spare bucket while the flue pipe is still hot. This gives me some warm water for cleanup. My sugar house is up in the woods too far from water and power so a lot of lugging.

I made my own with copper I bought from the orange home improvement store. You can see how I made mine a couple of years ago. https://youtu.be/jV5CUXEv6HA. Since then I have added to it to make it longer. Also, leave a little space in between the coils there is more surface area to heat up and it seams to work better with out the isolation.

On that same channel, I have some videos from this year that show my new setup.