Chilling out hey . . . so, why are people so bothered about this aspect of the process ? Well it achieves a whole bunch of things, not least of which is that it saves you time on brew day !
I used to put my 25 litre bucket of just boiled wort into the bath, 30 cm deep with cold water and then, with the lid on, occasionally twirl it. An hour later I had wort at around 25°C. Into this could go the yeast.
However, in that hour, any nasty bacteria could have a good head start on the yeast with all that lovely wort and my beer could've been a write off immediately. It happens. So, using some form of forced chilling, e.g. immersion coil or counter flow, can save a significant amount of time and force those bacteria beasties to give the yeast first bash at the wort.
So, there's two reasons immediately, neither of them trivial . . . (1) you save up to an hour from the process and, (2) you improve the chance of your beer not being infected . . . now, how many home brewers have ever dreamt of improving these two issues ?!
OK, in addition, there's the matter of proteins in your beer. You see, they're there in the malt and, whether you use extract or the real thing, they end up being dissolved in your wort prior to the start of the boil. And if they stay there until the start of fermentation, you will have them in your bottled / kegged beer and, if things get a tad cold, you will witness chill haze in your beer . . . damn, it was so clear in that bottle before it went into my fridge and now, after a couple hours of chilling in the fridge you pour a hazy beer . . . damn . . . doesn't affect the taste . . .just the visuals ! Ever experienced that one ? Get chilling . . .
The proteins, you see, dissolve during the mash (or are already in the extract syrup) and will present you with three chances of getting rid of them :-
Firstly, during the boil, some of the proteins automatically come out of solution. You'll see them as cotton wool looking efforts floating around the boiling wort. At this stage they are called the "hot break". You can improve their precipitation by going for a rollicking good boil (so they physically collide in the wort and stick to one another) and also by ensuring the pH is close to the 5.0-5.5 level. Outside of this they may be reticent to precipitate. Buggers that they are.
Secondly, when you chill the beer after the boil and before fermentation, more protein matter will come out of solution. You will see this as yet more fluffy looking stuff in the cold wort. This is referred to as the "cold break". And yes, you can improve the amount that precipitates, firstly by upping the chilling rate (i.e. how fast the wort is cooled) and secondly by forcing the wort to ever colder temperatures. In this you find another good reason for using a chiller . . . improve that cold break !
Thirdly (is that a word ?!) you can precipitate more proteins out of the beer if you add special finings to the fermented beer . . . but by then it might be too late to do as much good as you could have done by leaving it so late ! Rather go for the two previous points and do them well and save yourself the money on the special finings !
So, if you use a chiller to rapidly cool the wort from boiling down to pitching temperatures, you should help to chill-proof your beer . . gotta be worth a go eh ?!
Oh, and while I'm about it, maybe I should mention that proteins get eaten by bacteria in the long run so your shelf life will improve if you get rid of them. Shelf life you say ? Doesn't everyone drink it all in the same month that you bottled it ?
Chilling Equipment
So, what are the options you ask ?
The simplest to make is an immersion chiller. Here you buy about 8 metres (25 feet) of copper pipe, say 10-12 mm (half inch) diameter, you take great care in bending it around a round cyclindrical object and then you connect hose pipe connectors to each end. It'll end up looking like one o fthose kids "slinky" toy springs, sort of two thirds the height of your boiler in height.
The trick here is to buy the copper pipe that they use for air conditioning and refridgeration, its soft and bends easily (too easily sometimes !). The usual stuff you get at hardware stores is rock solid in comparison. Check the yellow pages for a refridgeration contractor. In Pretoria check Seal Center in Hermanstad, they have never let me down on a wealth of pipe sizes (metric and imperial) as well as every conceivable connector and o-ring you could dream up.
To use an immersion chiller you need to decide whther or not you are going to use it to chill the wort in the boiler or in the fermentor. It all depends on your equipment and the choices you have made. In my early days I would pop it into the boiler for the last 15 minuts of the boil (to sterilise it) and then , as soon as the boil was complete, turn off the boiler's power supply and then wack on the cold tap water through the middle of the pipe. If you left it be you had cold wort in one hour, if you stirred gently (without aerating !) you had cold wort in 7-8 minutes. Apart from working out how to attach hose pipe connectors to either end, this has got to be the simplest and lowest cost means to implementing yourself a chiller.
The more involved (but rewarding !) route is to make yourself a counter-flow chiller. For this we'll need a drawing to explain but, in essence, you now use two pipes instead of one, arranged concentric to one another and the hot wort goes through the middle of the inside pipe while the cold water goes in the opposite direction in the outer pipe.
I chill using a counterflow chiller which has 10 mm copper pipe surrounded by a water garden hose pipe. Its about 8 metres long. More when I've time !
