The faster you cool your wort off after your boil, the less likely are are going to bump into issues with off flavors from oxidation and bacteria contamination. Wort chillers are also used as a way to cold shock free floating proteins in your beer that will later cause “chill haze.” A good “Cold Break” increases the clarity of your finished beer by causing these proteins to drop out into your trub. There are two types of wort chillers: immersion and counterflow. An Immersion Wort Chiller is a coil of copper tubing (usually between 25′ and 50′) that connects to a hose attachment.
This type of chiller is placed in your brew kettle after your boil and cold water is pumped through the tubing. The wort heats up the water as it leaves the system and quickly chills your wort. Depending on the temperature of the water you are pumping through your system, your beer will cool below 80˚ F in 30-45 minutes (and sometimes longer if you don’t also use an ice bath).
A Counterflow Wort Chiller is much more efficient. Wort is pumped through copper tubing that is housed inside a hose or larger copper tube. The hose/larger copper tubing allows for cold water to be pumped in the opposite direction of the wort. In some builds (Chillzilla), the inner tube carrying the wort is spiraled which creates turbulence in the water hose. This increases surface area of copper containing hot wort that is exposed to cold water, and maximizes the chillers ability to cool your wort. A counterflow wort chiller can bring the temperature of your hot wort down below 80˚ F in under 10 minutes. This is a HUGE deal! Not only do you save time, but you also decrease your beers chances of oxidation/bacterial infection. Counterflow wort chillers can also be used in conjunction with an immersion wort chiller. Connect your chillers together with your immersion wort chiller closes in a bucket of ice water, and you’ll be ready to pitch your yeast in record time! Purchasing a counterflow wort chiller is definitely not cheap, but there are some great homemade builds out there. If your game check out the builds on Ronblog or Tiber_Brew’s thread on Homebrewtalk, otherwise support your local brewshop!