What are Chill Haze, Gravity, and Pitch: Brewing Terminology Tuesday
February 10, 2015
Welcome to our first Brewing Terminology Tuesday: your go-to source for all the brewing terminology you could ever need to know! There will be three terms a week to help advance your homebrewing knowledge. This week, we'll define chill haze, gravity and pitch as they relate to homebrewing. Chill Haze Simply put, chill haze is cloudiness in your homebrew caused by protein and tannins compounding at low temperatures. Most beers are clear at room temperature, but all you homebrewers out there know that, while your homebrew may taste better than commercial beer, it doesn't always look the same. When beer is chilled, proteins and tannins that are left in the beer compound together and create "clumps" that are large enough to reflect light, causing a hazy appearance in your beer. These clumps are heavier than beer, so if you let your beer sit in the fridge for a long period of time undisturbed, those protein clumps will settle at the bottom of your beer and not reappear until you start drinking it. So how do homebrewers avoid chill haze? According to Brew Your Own, the easiest way "involves using heat and cold in just the right way to drop protein out of the wort." What does this mean? "Boil as hard as you can, and chill as fast as you can." A rolling boil causes the tannins to collide with protein particles, effectively removing them from the beer. Then, the wort is rapidly cooled, the trub forms large particles and drops to the bottom, effectively removing many more of the proteins. For a more detailed description of chill haze and how it can be avoided, check out this article. Gravity First of all, there are different types of gravity referred to in the homebrewing world: original gravity, and specific gravity, or final gravity. You need a hydrometer to take a gravity reading. So what does the term gravity refer to? The total amount of dissolved sugar in your beer. Sugar is consumed by yeast, so as your beer ferments, your gravity will change. The original gravity (OG) should be taken before your yeast is pitched. The higher the reading, the more sugar is in your wort to be converted into alcohol. This means, a higher gravity reading means a higher finished ABV. You than use your specific gravity to track the progress of fermentation. Many recipes will tell you what your gravity should be around when fermentation is complete, or you want to take readings until your gravity has stabilized. Pitch This is our easiest terminology for the day. Pitch is the action of adding your yeast to your fermenter. You will want to aerate your wort before pitching your yeast, which can be done in several ways. One of the easiest ways is to simply stir your wart vigorously with a whisk or spoon. Once the wort is thoroughly aerated in your fermenting vessel, sprinkle your yeast on top of the wort. There is no need to stir… your yeast can eat away at the sugars all on its own.