A wort chiller is probably one of the most useful pieces of equipment a home brewer can have, allowing you to quickly cool your wort to reduce the risk of oxidation, achieve a good cold break, and generally speed things up.
The simplest wort chiller design is the immersion chiller; a simple copper or stainless steel coil through which cold water is run while it is immersed in your wort, effectively carrying the heat away from the wort. Although a simple piece of kit, they can be expensive to buy ready-made, so it is definitely worth considering building your own. And to help you decide whether this is an option for you, here's a short illustrated guide to building your own chiller.
First, a list of things you will need:
A form around which you can make the coil
A pipe bending spring (for 10mm pipes)
A length of garden hose
A short piece of syphon tube
A hose-to-tap connector
And optionally, quick snap fittings for joining hoses (if you follow this design!)
My former brew buddy Kieron and I made a great wort chiller before very cheaply and which you can read about here. The design presented here is a slight modification of that simple design. The main change being that instead of having two long lengths of hose permanently attached to the chiller, only two short pieces are permanently attached, each ending in a quick-fit- hose connector. This will allow a hose of any length to be attached, making it more flexible in terms of where you brew, and also a little easier to store.
Most articles you read about making a wort chiller recommend using a cornie keg as a form around which to bend your coil. We didn't have a cornie keg when making the first chiller, so used a large paint can. This was perfect as you could kneel on it and control the bending process pretty easily. I was going to go the same way with this one, but for some reason i wanted the long upright pipe to be on the inside of the coil. The best way I could think of for achieving this was to use a hollow tube as a form. In fact, a 200mm diameter pipe would be ideal. As I couldn't find one, the next best option was a thick cardboard tube with a diameter of 240mm. Whatever you choose, just make sure the diameter fits nicely for your boiler.
To accomodate getting the long upright inside the coil, a notch has to be cut into the base of the form. Simple enough. Before you start bending things however, you need to figure out just how long you want this upright to be, so to start, make it long enough to fit the full depth of your boiler, plus enough to put another bend in to take the end out and over the lip of your boiler.
Use the pipe bending spring to put a right angle bend into the pipe and then place your form over the upright piece with the notch over the pipe. The notch will also provide an anchor point for when you begin wrapping the coil.
When wrapping the coil you can either stretch the copper out and then rotate the form to pull and wrap the copper into a tight coil, or you can keep the copper in a roll and rotate this around the form, essentially tightening the “coil” formed by the roll. In this case I stretched the copper out, but mainly because I wanted to know if the guy had given me the 12 metres I had paid for. In fact, he gave me 14m! Either way, work slowly and carefully to keep a tight coil. It's not difficult to bend the copper, but if you make a mistake it's not easy to try to unbend it and bend it again, so take your time.
Once you get near the end of the copper roll, you need to think about the last short upright. You can choose whether to have the coil end beside the long upright, or have them opposite each other. It's up to you. I chose to keep them parallel, so made another right-angle bend to make the short upright, with enough extra to do the final bends.
The last two bends were made to allow the joining of the hose and copper to be outside the boiler, just in case there are leaks, or condensation forming and dripping into the wort. Once the bends are made, cut off any excess with a small hacksaw or pipe cutter for a neat finish.
Tip: If your boiler is deep, and you think you are going to end up with a short coil, consider making the bends in the upright in such a way that you can hang your chiller over the edge of the boiler. As heat rises, a chiller sitting at the bottom of your boiler will not be as effective as one hanging in the top area of your wort. With the last one we built we always had to lift it to keep it in the top half of the electrim boiler to cool the whole wort quickly.
Next cut two short pieces of hose which will allow standard garden hose quick-fit connections to be attached to the chiller. To attach the hose to the copper I have found that the best way is to use short bits of syphon tubing as a gasket, as the difference between 10mm copper and the inside diameter of a regular garden hose means that you will usually get serious leaks. Heat the syphon tube in boiling water to make it flexible, and slip it over the ends of the copper pipe. Slide on the two short lengths of hose and tighten the jubliee clips for a good tight seal. You can then attach the garden hose quick-fit connectors, and your chiller is essentially finished. All you need now are two pieces of hose long enough to reach from your tap to where your boiler sits, and for the outlet of the chiller to a drain or sink. A quick tip though, when using the chiller, make sure the cold water flows into the top of the coil for the most effective chilling. Heat rises and all that. :)
So, I hope this shows how easy it is to make a pretty good chiller for a reasonable cost. Enjoy! :)
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