Control your fermentation temperatures with Cool Brewing's simple, yet innovative, insulated fermentation bag. This is the 2nd generation Cool Brew bag, which has made cold fermentations even easier! Fermenting your homebrew at the right temperature is one of the critical factors in making good beer. Let the temperature get too warm, and your beer will taste 'rough' as the soft malt and vibrant hop flavors dissapear! Typically an advanced homebrewer would want to get a spare refrigerator or even a MoreBeer! Cooled Conical to control fermentation temperatures, both those options either take up a lot of space or can cost a fair amount of money. The Cool Brewing Bag allows the apartment brewer, those who have space constraints, or the brewer on a budget a great option to control fermentation temperature and make great beer.