>> Wednesday, February 26, 2014

Pickup (lower) and whirlpool (upper) ports
I read Jamil Z's article about whirlpool chilling years ago and it sounded pretty intriguing. The basic idea is to use a pump to recirculate your wort thus forming a whirlpool in your boil kettle. The whirlpool motion increases the amount of wort in contact with the immersion chiller coils resulting in a more efficient chilling process. At one point I tried to update my immersion chiller similar to Jamil's design, but my attempt was a bit kludgey and I soon abandoned it. Even though my first attempt didn't really work out, I figured I'd revisit at some point in the future when I had a chance to work out a better design.

Jamil's article focuses on immersion chillers, but he also mentions that you can recirculate through a plate chiller and accomplish similar results (bulk chilling). One benefit is you're able to chill quickly and get the entire batch out of the range in which DMS precursors can be an issue. Another benefit, the whirlpool motion aids in building that nice hop/trub cone in the center of your boil kettle. In theory, I should also be able to leave more cold break behind in the BK. Another benefit for me is I have a thermometer on my BK so I'll be able to chill to pitching temps whereas in the past I'd sometimes over-chill in the winter when ground water temps were lower. This can also come in handy when performing hop stands where you want to chill a little bit, then hold at a desired temperature before chilling completely.

So those are all the benefits. There are a couple possible complications from using this method. First is you want to make sure you have the ability to filter out hop debris that would otherwise clog your precious plate chiller. A hop bag, hop spider, inline filter, or a combination of these can be used to accomplish this. Secondly, it's important that the positioning of the whirlpool return is correct. You want to create a whirlpool, but avoid stirring up debris. Lastly, the chances of clogging something (chiller, filter, etc.) will be higher with recipes that call for more hops (especially pellet hops), so I may have to throttle back the flow a bit until a whirlpool is established.

As for my implementation, I recently upgraded from an 8 gallon kettle to a 15.5 gallon keggle. In order to be able to whirlpool, I added another ball valve above the pickup tube's ball valve. The port was added at the four gallon mark so that it will function regardless of whether I'm brewing a five or ten gallon batch. On the inside of the keggle there's a 90 degree street fitting that is positioned horizontally to create the whirlpool motion. The chilling circuit flows from keggle to pump to hop/trub filter to plate chiller then back to keggle via the whirlpool port.

I haven't brewed a batch since finishing this upgrade, but I did a test a couple days ago with water. I was able to knock the temp from boiling to 78-ish degrees in about six minutes. I'm hoping to brew this coming weekend, so I'll report back on how it all goes.