Bottle conditioning
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A bottle conditioned beer |
Bottle conditioned beers are either
unfiltered so the final conditioning of the beer takes place in the bottle, or filtered and then reseeded with yeast so that an additional
fermentation may take place. Not all bottle conditioned beers will referment in the bottle.
Priming is the process by which
beer is wholly or partially
fermented in the bottle from which it is served. This is done by adding a small amount of
yeast and sometimes
wort or
sugar to the bottle before it is sealed. Bottle conditioning is normally done to add
carbonation, and does not usually add much alcohol to the beverage.
Bottle conditioned beer are usually carbonated entirely by the natural action of the yeast, as opposed to filtered beers which are carbonated using high pressure gas injection.
Filtered beer tends to have a relatively short
shelf life, rarely more than a year, as many compounds in the sterile beverage break down into unpleasant tasting ones. Live yeast inside the bottle acts against these processes, giving the beverage a much longer shelf life. A good bottle conditioned beer can maintain its drinkability for many years, and some can be aged for decades.
Bottle conditioned beers vary in clarity. If the yeast remains in suspension, the drink can appear murky or even chunky. But if the yeast is dense and settles, the drink can be completely transparent with only a thin yeast layer at the bottom. The yeast solids are usually referred to as the
sediment or
dregs, especially once opened.
Serving such a beverage involves either
decanting the drink into the serving glass, leaving the sediment behind in the bottle, or pouring all the contents into the glass, including sediment, to be drunk together. This is generally a matter of personal preference, though sometimes the brewer will suggest a preferred method for a particular beer. Drinking the sediment has some nutritional benefits, but it does slightly change the flavor and mouthfeel of the beer. In some beer cultures, it's common to pour the sediment into its own
shot glass to be drunk separately.
Bottle conditioned beers are never
pasteurised. Thus they generally contain some live yeast.
Homebrewers sometimes take advantage of this by cultivating the yeast from famous beers to use in their own brewing. Some beers, however, use a different strain of yeast for bottling, which in effect contaminates the primary yeast that gives the beer its character.
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Cask ale*
Keg beer*
Draught beer*
Filtered beer
