A Bright Tank is a dish-bottomed pressure-rated temperature-controlled tank used to hold beer in preparation for packaging. The term “bright” refers to “bright beer,” beer that has been rendered bright (clear) by filtration, centrifugation, fining, and/or maturation. In most breweries, beer will be filtered after leaving a uni-tank or lagering vessel and be directed into a bright tank. If the beer is to be force-carbonated, then the beer may be carbonated in-line, under pressure, between the fermenter or lagering tank and the bright tank. In this case, the beer should arrive at the bright tank with full carbonation. For in-tank carbonation (or adjustments), the bright tank will be fitted with a carbonation stone, a device through which carbon dioxide is forced, dispersing fine bubbles into the liquid for fast dissolution. Carbonation stones are usually made from either porous stone or sintered stainless steel. After carbonation, the beer is ready to be bottled or kegged (or both) directly from the bright tank. As the bright tank is the last stop before the package, careful attention is paid to quality assurance at this stage. Carbonation is closely checked and the brewery’s laboratory will run a series of tests.
In larger breweries, color may be added at the bright tank stage, and adjustments may be made to bitterness and aroma using pre-isomerized hop extracts or hop oils. In craft breweries, bright tanks may play any number of roles besides those enumerated above. As many craft beers are not filtered or clarified, the beer sent into the bright tank may not be bright at all. The beer may have flavors added at the bright tank. The volatile flavors of honey, for example, do not always survive fermentation, and therefore many honey ales have honey added at the bright tank, where it will add some sweetness as well as flavor and aroma. Coffee or coffee extracts are also often added here for similar reasons. Bright tanks are also often used for blending one or more beers to create something new.
Bright tanks are also sometimes used as mixing tanks for beers that are to be bottle-conditioned. Here, the beer will be mixed with priming sugar and possibly with new yeast intended to carry out re-fermentation. The beer is then bottled (or, in rare instances, kegged) from the bright tank. In brewpubs, the bright tank is often also the serving tank; beer may run directly from this tank to the taps at the bar.