Finished beer is either bottled, canned or filled into kegs (K). It may be tunnel pasteurised, flash pasteurised or aseptically bottled. In either case the beer must appear fresh, bright and without faults to the customer and hence the quality is a matter of great concern. The beer must also be free from micro-organisms to ensure wholesomeness and biological stability. The ethanol content must obey fiscal rules but is also of major importance for the flavour of the beer. This is further influenced by a wide range of compounds that may be present in even very small amounts. Visually the finished beer (L) must form a nice foam on pouring, it must have an attractive colour.
Despite use of the choicest raw materials and careful brewing performance the beer is a fragile liquid, especially when not stored cold. The fine balanced aroma of fresh beer is eventually replaced by a less attractive smell and likewise the taste deteriorates. The basis for this decay is a matter of intense research.