Counterflow Chiller – The Making Of (ULCBP)

When John heard about the Ultra Low Cost Brewery Project he was more than a little excited.  Not only did he want to get involved and make some tasty brews, but he kindly wanted to make a contribution.  One thing the project doesn’t have is a wort chiller, so he took it upon himself to knock one up.

What is the point of a chiller?  It sits between the boiling kettle and the fermenter and allows you to rapidly chill the wort post-boil.  This locks in the aromatic oils of the hops.  It also means that the wort doesn’t cool slowly, so it doesn’t sit at the infection temperature for extended periods of time.  These are both good things.

There are a few approaches for chillers.  By far the most common is simply a copper coil that is lowered into the kettle and water is pumped through – known as an immersion chiller.  This approach wins out for its lack of complexity and low cost, but it doesn’t cool the wort exceptionally quickly and it doesn’t allow for some advanced brewing techniques (such as a hop-back).

The other type is inline chillers – which are essentially heat exchangers that sit between the kettle and the destination vessel and chill small quantities of wort very quickly as they leave the kettle.  We settled on the counterflow chiller (CFC) design where you have an small inner tube carrying wort surrounded by a larger outer tube carrying water in the opposite direction (hence counterflow).

You can do this with some small diameter copper tubing and a garden hose outer, but being a man to do things correctly John opted on a full copper CFC.  The tubing he used was airconditioning pipe and the first mission was to feed 7.5m of small tubing inside a larger one.  Plenty of washing-up liquid, water and patience required!

At times this required a little loving tap with a hammer – but be careful because this annealed pipe kinks very easily.  Make sure you thoroughly deburr the pipes before you start – you don’t want to make life any harder than it already is!

Next step was to neaten things up a little and roll the whole lot up around an appropriate form.  We chose a keg, as a bend radius any smaller than 13″ will cause kinking.

Next you have to make the whole think water-tight.  John found some reducing T-adaptors.  You will need to file out the ridge so that the small pipe can pass all the way through the T.  This is a tedious task, but resist the temptation to reach for the dremel – a round file proved (yet again!) far faster.  Then it’s time to crack out your soldering skills and make it all permanent.

Below is the finished product.  Quick fittings for garden hose is a good idea.  The vinyl lines for wort in and out I am yet to be convinced about – this liquid is going to be hot!  But it all needs a trial run, and no-doubt some refinement will ensue.

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