Maceration and Fermentation: New Technologies to Increase Extraction

Abstract Red grape fermentation is a complex process in which the fermentation of sugars occurs at the same time as skin maceration together with seeds and eventually stems. Fermentation is a biological process produced by yeast, and maceration is a physicochemical process which requires the extraction of anthocyanins and tannins to obtain the color and structure typical of red wine. Control parameters of both processes are different, so it is necessary to optimize the compatible conditions to manage each of them. Temperature, mechanical operations, and aeration are useful to increase extraction and improve the final balance of phenolic compounds. The main drawback of conventional red wine making processes is the requirement to work with solids (skins and seeds). Emerging technologies not only facilitate the separation of solids with suitable extraction techniques, but at the same time reduce wild microorganisms. This allows an easier management of fermentation as well as the implementation of new biotechnologies such as non- Saccharomyces fermentations and yeast–bacteria coinoculations.