Polyphenols, also known as phenolics and polyphenolics. They are a group of chemicals produced by plants. They include a number of important components in wine such as tannins, flavours (also known as flavonoids). Flavonoids are also important for red wines. Not only do they impart flavours, but also colour, known as anthocyanins. In general high levels of polyphenols are found in the skins of most plants, as well as the seeds and steams. That’s why tannins, colour and some flavours are extracted from the skins by leaving them in contact with the fermenting juice. This is known as Maceration, and is essential for red wine production. White wines do not normally have any skin contact, and get most of their phenolics from the phenolic acids found in the flesh of all grapes. While most phenolics in wine come from the grapes, not all do. For example, the phenolic vanillin, which gives wine a vanilla flavour and comes from the wine in contact with oak (often barrels, chips or dust).
Wine is often said to be healthy and it is generally thought polyphenols have an anti-oxidative effect, and while no consensus is reached on the mechanism or even the exact polyphenol, wines that have dark skins and high tannins are known to have high levels of polypehnols, and are the most likely to help reduce heart disease.
Below is a list of different types of polyphenols.
Tannins are responsible for the drying almost astringent taste in the mouth and usually come from the skin and seeds, although the stalks do contain tannins.
Anthocyanins are responsible for the colour of red wine and the pigmentation comes primarily from the skin of the grape.
Procyanidins are thought to improve blood flow in the body and reduce the risk of heart-related disease. They are often found in wines that are high in other polyphenols rich wines such as tannins and anthocyanins.
Flavonoids are subset of Polyphenols and include Anthocyanins and Catechins. They are the largest know subset of Polyphenols and make up to 90% of the Polyphenols found in red wine.