Fermentation and its extraordinary complexity. The production of wine depends on fermentation, and for this to happen the involvement of microorganisms, invisible to the human eye, are essential. These tiny microbes seek no more than any other living being: to live and perpetuate themselves. In this search for subsistence, they feed and reproduce, carrying out metabolic processes throughout their lives that result in a complex and tasty wine.
In this chapter, besides examining the life of yeasts and bacteria and their classification, we explore all types of fermentations, paying special attention – given their importance – to alcoholic and malolactic fermentation. The winemaker has multiple choices at this point of the winemaking process. The temperature and supervision of the grape must, the procedure for yeast or bacteria inoculation, how the whole process is controlled… these are all variables that will result in wines with very different profiles.