Condensed tannin extracts in oenology: chemistry, botanical sources and applications in winemaking and aging processes

Given their economic, cultural, technological, and environmental implications, wine and winemaking have long been the subject of scientific studies in their many aspects, as well as condensed tannins, among the most abundant compounds in grapes and wines. Condensed tannins play a fundamental role throughout winemaking, particularly during maturation and aging, and can be used in oenology to improve wine quality, according to guidelines of organizations such as the International Organization of Vine and Wine and government regulations. This review examines the main scientific findings on the chemical nature and classification of condensed tannins, their botanical sources, properties and mechanisms underlying their oenological applications, including effects on sensory profile, oxidation control, colour stabilization and microbial control. This topic has proven to be vast, complex and extensively studied, also thanks to the development of advanced analytical techniques. Despite this, several aspects still require further investigation.