Cleaning and Chilling the Wort
When the boil is over create a whirlpool with a long, clean spoon. This will draw the sediment, called trub, into the center of your kettle. You can then drain or siphon the wort from the side of the kettle leaving the trub behind. Try not to splash the wort too much. Introducing oxygen to hot wort can create unwanted flavor and color changes in the final product. The wort can be further filtered through a 2 inch bed of loose hop flowers in a strainer or hop back. While this will introduce some fresh hop qualities to the final beer, our purpose here is to produce clearer wort. This should be done before the wort cools to below 170F to prevent infection. You might want to put the first running back through until the hops have settled for the best filtration.Now it is time to chill the wort. Wort chillers are simple heat exchange devices that quickly cool wort by placing it next to cold water, usually through some sort of copper tubing. An immersion chiller is nothing more than a coil of copper tubing that is dropped into the hot wort. Cold water is run through the tubing quickly cooling the wort. A counter-flow chiller is a tube within a tube. The wort flows through the inner tube in one direction while the cool water runs through the outer tube in the other direction. When the wort emerges from the other end it has been cooled to the temperature of the water.
Cold Break
There is also a cold break that removes the proteins that can cause chill haze. Most homebrewers don’t need to worry about this. Chill haze doesn’t negatively affect the beer and creating a cold break requires equipment that many homebrewers don’t have. However if you are brewing competitively, want an especially clear pale ale, or regularly brew lagers you probably want to produce a cold break.The cold break essentially happens in the same way as the hot break. The wort is cooled to the point where dissolved proteins are forced to precipitate and fall out. Typically you won’t need to cool below 38F though some commercial brewers take it so far down the ice begins to form. The resulting beer is especially clear because doing so precipitates so much out of the wort. It is also less flavorful for the same reason. After the cold break the wort should be racked off of the trub into the primary fermentation container. It is important that this cooling period happen as quickly and cleanly as possible because this is the time that your wort is most susceptible to infection.
Fining Agents
Creating a cold break is indeed a troublesome process even for the most sophisticated homebrewer. Fining agents provide a simple way around it. Working in much the same way as the hop polyphenols described above, fining agents are added towards the end of the boil or later in the fermentation tank. Here are a few of the most popular.- Irish Moss
- Gelatin
- Isinglass
- Polyclar
Pitching the Yeast
Whether you use the cold break or skip it, once the wort is at the optimum temperature for your yeast – the range usually appears on the packaging – you are almost ready to pitch it. But first the wort must be oxygenated. The boil left it in an oxygen starved state and yeast requires oxygen to survive. This isn’t a particularly complicated process, you simply need to introduce as much of the wort to air as possible.Vigorously shaking the carboy and agitating the wort all the while keeping the top covered with a sterile hand should do the job. There are also pumps available that will pump air into the wort for you. Once you’re satisfied that the wort is properly oxygenated, it’s time to pitch your yeast starter into the wort and let the fermentation begin.
