The unitank/fermenter is the most common style of fermenting vessel. Yeast is added to the wort and controlled fermentation takes place. Fermentation times vary greatly depending upon beer style, type of yeast and fermentation temperatures. The size and number of fermenters are two major factors that determine the annual production of a brewery.
The brite tank is used for carbonating the beer and the beer is then either served direct from this vessel via beer lines to the tap (commonly seen in brew pubs) or is kegged and/or bottled (as in a microbrewery). In brewpubs the number of serving tanks generally determines the number of different beers on tap.