How do tannins affect the flavour of wine?

Some types of red wine make your mouth feel ‘dry’ when you drink them. New research into why this happens finds out why tannins affect the flavour of different wine types.

The character and quantity of red wine tannins are often affected by different factors. These include how thick the grape skin is, the climate of the growing season and how the wine is cellar stored.

 

Different wine types affected by tannins

Researchers have published their findings in the latest issue of the Journal of Agricultural and Food Chemistry regarding the effect of tannins. They show that the tannins in Cabernet Sauvignon, for example, are more numerous, contain more pigment and are physically larger than the tannins in Pinot Noir.

They experimented by extracting tannins from a Pinot Noir and a Cabernet Sauvignon and discovered that tannins from Cabernet form more protein in saliva. This backs up previous research that shows wine can cause a dry mouth sensation when proteins in tannins and saliva interact.

 

What are wine tannins?

Tannin is a polyphenol that appears naturally in plants, wood, leaves, seeds, bark and, of course, fruit skins. In wine, tannins add astringency, bitterness and complexity of flavours.

Wine tannins are usually present in red wines however it is possible for tannins to be present in white wines if they are oak aged. Tannin is dry and tasted in the front part of the mouth as well as the middle of the tongue. An easy example to try of pure tannin is in unsweetened black tea.

Tannins in wine come from either the grapes or the wood of the barrels it’s aged or stored in. Grape tannins are in the stems, skins and seeds of the grape, and as red wines have more contact with the skin there is more time for tannins to dissolve in the liquid. On the other hand, wood tannins dissolve in wine if they are in contact with the liquid.

Examples of red wines that are high in tannins include Petite Sirah, Monastrell, Nebbiolo and Cabernet Sauvignon. Lower tannin wines include Zinfandel, Grenache and Pinot Noir, which is why the researchers used Cabernet Sauvignon and Pinot Noir to discover more about tannins.

 

Different factors affect wine taste

The researchers also found that tannins don’t make these changes happen on their own. Other factors within wine affect the tannins and how they affect the flavour and taste of the wine.

In the article, the team of researchers say: “When the opposite type of tannin was put into Cabernet or Pinot wines, the sensory panellists could not detect differences in dryness. For example, when Cabernet tannins were added to a Pinot wine, the drink appeared to have the same dryness as the original Pinot.”

They also point out that aromas from the wines would also have influenced the test panellists’ perception of the flavour of the wine.