Brewing was one of the earliest processes to be undertaken on a commercial scale and consequently, it became the first biological process to develop from a craft into a technology. Although the production of beer is a relatively simple process, the finished product is unstable when in its final package: bottle, can, or keg. As well as being susceptible to microbial infection, nonbiological instability (physical or haze, flavor, foam, gushing, light) involves a number of complex reactions with proteins, carbohydrates, polyphenols, metal ions, oxygen, thiols, carbonyls, and temperature. Although our understanding of these reactions has progressed significantly from 1975 to 2015, we are still far from a complete comprehension of beer instability/stability reaction systems.
