Home Brew Equipment - Wort Immersion Chiller

A wort chiller is used to cool the boiled wort from boiling, down to about 30°C so that the yeast can be pitched.  The quick chilling of the wort causes the "cold break" (the "hot break" coming during the boiling phase).

Ours is an twin-coil immersion chiller, which means it sits in the boiler and cold water is pased through the copper pipe, cooling the wort in which the chiller is sat.

Our garden hose is connected to the blue valve and cold water is passed in through the blue valve.  The pipe splits to feed the bottom of both the inner and outer coil.  The cold water then flows up through both coils and passes out through the red valves (to which lengths of hose are also attached).  The valves allow the inner and outer coils to be isolated, but in reality we always have both coils open.

The outer coil is 25cm in diameter and is 16 rotations.  The inner coil is 17cm and 14 rotations.

Here's the two coils in construction - just before the cold feed was added to the inner coil.

 

On a brew day the chiller has a spray of disinfectant spray, a scrub and a good rinse with warm and cold water in the shower before it goes in to the boiler for the last hour to sanitise the chiller.

Once the boil is complete the elements are switched off and the cold inlet is opened on the chiller.  The chiller cools from boiling to 30°C in about 10-15 minutes.  Then out it comes - all covered in hops.

There's not much more to say really other than to list the various plumbling hardware that have been used to create it, and the basic construction approach.

• 10mm copper microbore - this is by far the bulk of the financial expense. I got 25m for £45 from Screwfix and used 19m in total.
• 15mm copper pipe - about 2 metres to provide the vertical and horizontol pipework.
• 2mm x 20mm x 3m aluminium for the spacer stand and the horizontal bracing. The outer spacer is 40cm high and the inner is 35cm.
• 4 x 15mm to 10mm reducers
• 5 x 15mm elbows
• 1 x 15mm equal tee
• 3 x 1/2" or 3/4" washing machine values
• 3 x hose connectors - these and these
• Some hose
• Various M3 nuts and bolts for the bracing some pipe clips to hold the upright pipework to the coil.

Tools: Pipe cutter, spanners/mole wrenches, files of various sizes, drill and bits. 

We used compression plumbing fitttings as this is what we were comfortable using. Solder would have been neater and cheaper, but we didn't have the tools or the experience to do the soldering.

We built the outer coil to stand above our kettle elements in our boiler and within the hop filter, so you'll need to decide what height and diameters you want to go with. The top of our outer coil is slightly higher than the 32 litres of wort in the boiler, so in hindsight we could have had one less rotation on the outer coil.

The holes in the spacers are drilled at 20mm intervals, meaning the gap is 10mm, so this will allow you to work out the total number of rotations you require in order to achieve your desired coil height. Ours are 16 on the outer and 14 on the inner.

Our tip is to roll the microbore around something solid which is the same diameter as you want. You'll want at least half a rotation extra to allow some margin of error when connecting everything up.

When you mark out the series of holes on the spacers remember to make the holes on the second and third spacers progressively higher to allow the coil to rise :) About 7mm higher in our case as the hole interval is 20mm: 20/3 = ~7mm. So the first spacer has holes at 7cm, 9cm, 11cm etc, the second spacer at 7.7cm, 9.7cm etc and the third spacer at 8.4cm, 10.4cm etc. The holes are 10mm in diameter, but (in hindsight) if you can find one go for 10.5mm or 11mm as the microbore isn't always 10mm - which is why it took us so long to thread the spacers on to the coils!

When you thread the spacers on make sure you put the third spacer (with the highest series of holes), i.e. the highest hole is threaded on the bottom of the coil first. My brain hurts if I think about this too much - you'll figure it out ;)

More pictures here.

Dave & Suki.