Updated: Nov 16
I hate using something once and then throwing it away. I've seen many wort chiller set-ups where a garden hose is hooked up the the heat exchanger, the flow is turned to full blast and then the hot water runs right down a drain. Some homebrewers run the hot water into buckets to use for cleaning - this is great! But the amount of water to chill is often close to twice the wort volume.
At our brewing project, we built an extremely efficient heat exchanger that not only saves the hot water, but uses less water overall to cool the wort. With this setup, we can chill 6 gallons of wort to below 80 degrees with 5 gallons of water in 7 minutes!
This setup uses a plate chiller and counter-flow chiller in a clever configuration. I can't claim any credit for the idea, but I have tweaked the design to fit our brewing equipment and set up.
Rather than describe how the heat exchange happens, I created this diagram below that shows the flow of liquid.
The day before brewing, we fill a 5-gallon keg with water and put it in the cooler to chill down overnight. Just before we start the chilling process, the cold water is dumped into the HLT and then pumped into the chiller system as the hot wort is pumped in the opposite direction.
The hot water that emerges from the chiller is re-directed into our insulated mash tun to conserve heat until we start clean up. Since we use the dual-exchange set-up and a flow control valve, the water that goes into the mash tun is VERY hot.
KEEPING IT CLEAN
Anyone who uses a plate or counter-flow chiller has anxiety about the cleanliness and sanitary conditions of the chiller. It's not like you can stick a brush in there and scrub it out each time. Here's our process:
Clear the wort and trub from the chiller by pumping hot water through it.
Fill the kettle with some hot water and add PBW.
Hook up the chiller in reverse and pump PBW in reverse back into the kettle through the whirlpool arm. Run this loop for 10 minutes.
Stop the pump and hook up the chiller in the regular (forward) flow configuration. Turn on the pump and run the PBW loop forward for another 10 minutes.
Pack the chiller with PBW by closing off the "Out" valve, then close the "In" valve.
Let the chiller sit full of PBW until the next brew day.
Fill the kettle with a few gallons of Star-San.
Clear the PBW out of the chiller by pumping Star-San in.
Hook up the chiller to the whirlpool arm and run a Star-San look for 5 minutes.
Close off the chiller and let it sit packed with Star-San until it's time to chill the wort.