Over, the last 20 years wine-making technology has seen remarkable developments, which have improved the quality of the wines produced and have also made it possible to prepare wines with a range of characteristics. In this field, some biotechnological techniques have been of fundamental importance. Among these technological innovations, enzymic treatments, selected yeasts, improvement of microbial starters, and microorganism immobilization are reviewed here. A concise report is presented on the possibilities offered by enzymes that catalyze the transformation of polysaccharides, proteins, and polyphenols. We illustrate the importance of the characteristics of wine yeast and of a genetic improvement program for the wine industry, as well as the complexity of the genetic modifications of commercial wine yeast strains. We summarize the research on the;optimization of new processes such as the use of immobilized microorganisms and cell-recycle batch fermentation in the preparation of wines and sparkling wines.