MICROBIOLOGICAL PHASES OF SPONTANEOUSLY FERMENTED BEER

Abstract

Fermentation is traditionally divided into two types of fermentation bottom and top fermentation. There is a third type of fermentation, which is traditionally used for spontaneously fermented beer. Spontaneous fermentation runs slowly because starts without inoculation. All of the 100 species of yeasts and more than 50 species of bacteria that were obtained from this beer come from the environment. A wide spectrum of microorganisms is discriminated on base of substrate usability, pH and alcohol tolerance, temperature, and speed of growth. So, fermentation is divided into different phases as normal one-organism fermentation. Phases are: the phase of Enterobacteriaceae, the phase of main fermentation, the phase of acidification, and the phase of maturation. Every phase is specific for the mostly obtained microorganism, specific metabolites, or technological processes. During 3 years of fermentation in every cask, a unique product with terroir will arise. Understanding this process is necessary to apply its interesting parts to new beverages productions and other fermentation technologies.