What are Tannins in Wine?
A group of astringent, bitter compounds, tannins are an essential part of wine. Naturally occurring, they exist in the fruits, bark and leaves of many plants, including grapes.
The seeds, skins and stalks of grapes all contain tannins, and when these are fermented with the juice – as is common practice with red wines – some of these tannins are transferred into the finished wine.