Friday, July 23, 2010

Recirculation Immersion Chilller

...and now, for some chilling.  Literally.
I got this idea from Jamil Zainasheff on his website  Jamil shows his Whilpool/Immersion Chiller in great detail on his site.  He's also discussed this modification to his homebrewing system on his internet radio show, The Jamil Show.  While many others go to fancy counterflow chillers or plate chillers, there's actually some good benefits to using an immersion chiller (see Jamil's website for a good discussion on the pros and cons).  The biggest downsides, however, is that it takes longer and uses lots more water.  Adding a recirculation element or whirlpool allows the wort to constantly be moving inside the kettle while the chiller is in the process of heat exchanging.  This increases the surface contact of wort to the chiller, effectively improving chilling time and water efficiency.  Adding a recirculation element to an immersion chiller can bank on the benefits while strongly chiseling away the downers.  Today, I improved upon my wort chilling system to increase water efficiency and to decrease the time needed to take wort from 212°F to less than 80°F.

I made a bigger wort chiller about 2 years ago with 50 feet of 3/8" OD copper.  While it looks like a job well done, I've had some minor issues.  First, 50 feet is a long distance and you need to have decent pressure to push water through that much restriction (maybe 50 feet of 1/2" OD would have made this better?).   I've attempted to use a pump to recirculate ice water through the chiller with limited success (works for several minutes at a time but stalls often).  The pump simply experienced too much back pressure.  Second, while I attempted to make good bends in the copper using a spring bender, I ended up making a few kinks which drastically increased restriction on an already overly distant length of 3/8" copper.  Here's a couple of pictures when I had just finished building a larger chiller.  Notice the kinks from too sharp of bends on the upper image.
Immersion Chiller built 2 years ago.
The new chiller keeps hop trub in the center while cooling much of the column of wort.
So the first order of business before adopting Jamil's whirlpool idea is to remove those kinks!  With a pipe cutter, I was able to remove the kinked locations and ended up taking off about 3-4 feet of copper.  Even though only a few feet, every little bit of restriction helps.
Several of my previous bends caused kinks in the copper pipe that limited the flow of water.
After a couple of chops, all kinks were eliminated.
After cutting out the kinks, the next challenge was to carefully bend the pipe to meet the kettle lid's notch without creating too sharp of angles or additional pipe.
Spring pipe benders are really useful for creating the curves on your wort chiller.
I found using a spring pipe bender (available at hardware stores near the copper tubing) useful to avoid making kinks.  You simply need to be patient and have enough pipe for leverage when bending.  Over bend each time and bend back to desired position.  Bends close to one another can be very challenging.  Just know that its tough to make different curves in a close sequence.
Refurbished and kink-free immersion wort chiller.
After trying this out with today's Kölsch, it works so much better.  At the end of chilling, I usually blow out the excess water and it was drastically easier to blow it out this time.  Also, the back-pressure on the tubing usually causes a leak on the IN-tube.  This didn't occur!  I suppose I can try pumping ice water again with my March Pump.

Onward to adding the recirculator/whirlpool:
I took about a foot section of the removed copper pipe and worked some angles so that beer can be pumped from the kettle spigot, through the kettle lid notch, and directed to flow alongside the immersion wort chiller.
This length was cut from my wort chiller and reshaped to direct circulating wort flow.
Using the spring pipe bender makes bending easier on the most part.  At least, it help you avoid kinking.  I would suggest working with pipe sections several inches longer than you anticipate.  Otherwise, its nearly impossible to bend near the end of the pipe.  You can always cut off excess later using a pipe cutter (about $10 at the hardware store).  Also, you should keep some sand paper on hand (220 grit sandpaper and a 400 sanding sponge seemed to do the job well) for sanding down those rough edges after cutting.  Don't forget to wash and rinse well before using! 
Immersion wort chiller with recirculation arm to move hot wort circular around the immersion chiller.
Here's how I do my wort chilling.  At the end of my brewing session, I stir the wort with a large spoon and get the wort moving fairly quickly in a circular fashion.  While stirring, I slowly move the stirrer towards the center of the kettle to create a whirlpool.  After waiting several minutes to allow the whirlpool to come to a halt whilst center settling the hop and trub, I slowly add the clean wort chiller to the center of the pot (most of the hop trub will remain in the center of the chiller's coils).  I allow the chiller to "bake" for several minutes for sanitation purposes.  At the same time, I arrange the pump to draw from the spigot and return to the kettle via the recirculation arm.  You can see this crafty shaped piece in the picture above.  As soon as possible, I begin recirculation prior to chilling to also "bake" the high-temp lines, pump (this pump handles high-temps), and copper pipe.  After sanitation is complete, I turn on the chiller using hose water.  Today, I think I cut my chilling time and water usage in half.  Not bad considering that summer temperatures have increased the temps of tap water and my black hose soaking up the summer heat isn't helping either.
Here, you can see the pump setup.  The bucket collects heated water from the immersion chiller.
During the summer months around here, the process of chilling the wort can take longer than the rest of the year and a better solution is needed.  I bought this pump towards the end of last season so that I can recirculate ice water through my immersion chiller.  It seems that the recirculator arm is more useful.  If I had two pumps, I could do both recirculation of wort and utilizing ice water.
Jamil's setup has two exit points for the wort though I'm not sure its necessary for a 5 gallon setup.  Click Here to see Jamil's Whirlpool/Immersion Chiller for some more info.
Only one potential issue to address.  I did notice that some hop fragments managed to collect at the incoming pump connection.  I have a QD here (quick disconnect) that has a plastic + going through the center of where the wort flows.  This cross hair of plastic picked up some hop matter and likely slowed the flow at some point.  I might need to add a filter element in the kettle or along the line to deal with this.
The pump was very easy to clean.  While the pump was running, I slowly closed the kettle valve and slid off the tubing.  The pump returned the remains to the kettle and then the pump was shut off.  I removed the recirculator arm.  I put the incoming tubing in the water bucket and pumped fresh water through the system.  I took off the QDs and dipped them in water to remove the hop matter that collected.  Last, I put the incoming tubing in a bucket of sanitizer (StarSan) and pumped that through for just a bit.  Finally, I removed the tubing for air drying.  Very minimal effort for a huge increase in chillindamos!

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