We’ve posted several articles about the various methods of chilling your wort after brewing, and even using a pre-chiller, but I realized that we hadn’t gone into much depth on the various chillers, other than how to build a DIY immersion chiller. Today, I wanted to talk a little about one of the more efficient (yet more expensive) chilling methods – a counter-flow wort chiller.
A counter-flow chiller works great if you are trying to chill more than 5 gallons of beer at a time. For my 5-gallon batches, I had been using the immersion chiller that I built and it works great. It is much bigger than what you can typically purchase at the store, and by building it yourself, you can some money. However, as with any immersion chiller, it can take upwards of 20-30 minutes or more to chill a 10 gallon batch of brew, depending on the temperature of your tap water. This is because the chiller is immersed into the hot beer and only comes into direct contact with the liquid that is actually touching the chiller, causing it to take much longer to cool the beer that is further away from the chiller.
Think of it as an ice cube in hot water. The water near the ice cube cools off, but the water away from the ice cube stays hot for a long time (or until the ice melts).
The advantage of a counter-flow chiller is that the beer itself flows through the copper coil and cold water is pushed around it in a hose. This means that a LOT more of the beer actually comes into contact with the cold copper, resulting in a much quicker cooling time. I can basically let the wort start flowing from the kettle, through the chiller, and by the time it gets to the fermenting bucket, it will be room temperature – perfect for pitching yeast!
It still takes 15-20 minutes to chill the whole batch, but each piece of liquid goes from boiling to room temperature in a matter of seconds, which is what causes a better hot break, less chance of infection, and hopefully better resulting beer!
Building a Counter-Flow Chiller
Building a chiller is best done by someone who knows how to solder. Granted, it is a fairly simple soldering project, so it could be a good time to learn! You could also use compression fittings, but it is more likely to leak.
I am not going to post the step-by-step because we followed the instructions provided by Bobby on homebrewtalk.com. He gives great step-by-step directions, so I don’t want to regurgitate them to you here.
The basic premise is that you thread a copper coil inside of a heavy duty high-temperature garden hose. The cold water goes through the hose on the outside, and the fresh wort goes through the copper coil in the opposite direction, allowing for the rapid cooling.
A simple aquarium thermometer on the output will show you the temperature of the wort coming out, so that you can adjust the flow to hit the perfect pitching temperature for your brew.
You can also purchase a counterflow chiller pre-made, if you’re willing to drop a little more cash. And some of the pre-made ones are more compact and also are built using a twisted coil to cause more turbulence to the wort traveling through the chiller, resulting in increased efficiency. Also, some of the pre-made ones use stainless steel which is a better material than copper, but is harder to work with and more expensive, so if you’re building your own, I recommend copper.
You can also purchase the Blichman Thrumometer as an attachment to read the temperature of the wort exiting your chiller, but as I mentioned, you can also just build one using a couple of copper connections and a adhesive aquarium thermometer from Pet Smart.