In the case of ales, this process is referred to as Cold Conditioning, and is a popular practice at most brewpubs and microbreweries. Cold conditioning for a week clears the beer with or without the use of finings. Fining agents, such as isinglass (fish bladders), Polyclar (plastic dust), and gelatin, are added to the fermentor to help speed the flocculation process and promote the settling of haze forming proteins and tannins. While much of the emphasis on using finings is to combat aesthetic chill haze, the real benefit of dropping those compounds is to improve the taste and stability of the beer.When the beer is conditioned at low temperatures various processes take place that lead to the smooth character which is expected from a lager. Proteins and polyphenols (tannins) bind with each other to form larger molecules which become insoluble and precipitate out of solution. Hop polyphenols will drop out leading to milder hop bitterness. Some of the alcohols and acids form esters in the beer which leads to new flavor compounds. This process is very slow and becomes only significant after more than 12 weeks. Some yeast activity may be present which leads to further clean-up that removes the yeasty smell and taste associated with young beer. Also, it is not uncommon to see extract reduction of the beer where an extract drop of 0.1 – 0.2 Plato over the course of a few weeks can occur.
