Definition: wine tannins

Tannins – What role do tannins play in wine? Have you ever bought a bottle of wine that you wanted to drink straight away, only to find that it tasted slightly bitter and unbalanced on the palate? Far from being a sign of poor quality, you may simply have chosen a good bottle that was not intended for immediate consumption, a vintage that would have benefited from being kept for a while until the tannins were well coated and it could reveal its full potential in complete harmony. The moment of opening was simply not optimal. Tannins have the characteristic of promoting the preservation of wine, as well as affecting its texture and taste, while also having a beneficial effect on health, which is far from negligible. White wines contain much less.

Current trend in vineyards and cellars:
In the past, storing wines in your own cellar until they reached their peak was an absolute must, especially for quality wines in the higher price segment. Nowadays, thanks to new winemaking techniques adopted by innovative winemakers, a growing number of wines are ready to drink almost as soon as they are purchased. Three elements play a key role in achieving this result: acidity, fruitiness in the wine and, in particular, tannins, whose structure and concentration will determine whether the consumer perceives a young wine as bitter and unfit for consumption or already harmonious and pleasant on the palate.
The demand for wines that are ready to drink upon purchase has been particularly supported by overseas consumption habits, where wine was more associated with a certain lifestyle, with wines being purchased to be drunk immediately. Winemaking methods have therefore been adapted to this trend, with winemakers producing wines that meet this demand – with lots of fruit and soft, well-coated tannins.
In Europe, where wine has been part of the culture for centuries, winemakers produced wines that needed to be kept for a certain amount of time after purchase in order to develop a beautiful harmony between tannins, acidity and fruit. Today, the younger generation of winemakers also produces wines that are more geared towards market needs. They strive to produce wines that combine complexity and long ageing potential while reaching their peak earlier.
The role of tannins:
Tannins are plant substances found in the skin, seeds and stems of grapes, as well as in the wood and bark of oak and chestnut trees and many other plants, such as tea bushes. The concentration and structure of tannins in wine can be influenced by the winemaker in the vineyard and during the winemaking process in the cellar. In the vineyard, the degree of ripeness of the grapes has an effect on tannin density. It is important that the grapes reach full phenolic ripeness, i.e. they should not be harvested before the berries are fully developed. In practice, the winemaker tests phenolic ripeness by chewing the berries at regular intervals to check their stage of development, until they no longer release green and bitter aromas. The climate also plays a major role and it is not always easy to find the right time to harvest.
In the cellar, winemakers can influence the tannic density of wines through various winemaking techniques. For example, they may decide to use only the grapes or to add the stems during maceration. During pressing, pressure also plays an important role, as it influences the amount of tannins that will be extracted from the skins and berries and end up in the must. The duration of maceration and the regular pumping over of the fermenting must onto the cap of marc also determine the tannin density of a wine. During the stabilisation phase, the use of barrels or, for less expensive wines, the addition of wood chips also influences the tannin concentration of the wine. Finally, before bottling, the winemaker must decide whether to clarify (= remove suspended particles) or filter the wine, or leave it naturally cloudy. All these winemaking methods ultimately determine the tannin density of the wine and, therefore, its more or less mellow appearance when it goes on sale.
Perceiving tannins when tasting wine:
Tannins are difficult to detect on the nose, just as a darker colour does not necessarily indicate a very tannic wine. The best way to assess tannin concentration is through tasting. When it comes to the taste buds on the tongue, sweetness is perceived at the tip, saltiness at the front sides, acidity in the middle and at the back of the tongue, while tannins are perceived at the base and on the palate in the form of a rough sensation of dryness and slight bitterness. Oenologists refer to this as the astringency of a wine.

Grape varieties rich in tannins:
Among the grape varieties that are very rich in tannins are Cabernet Sauvignon, found all over the world; Cabernet Franc, originally from the Loire Valley in France; Malbec, the grape variety of choice in Argentina; Spanish Tempranillo; Italian Sangiovese; Mourvèdre from the south of France; and Touriga Naçional from Portugal.
Conclusion:
Regardless of whether you choose white or red wine, tannins are a determining factor in quality. They help slow down the natural oxidation of wine and give it structure. If they are not sufficiently integrated, tannins can detract from the tasting experience, whereas if they blend harmoniously with the acidity, sweetness and aromas, they can significantly enhance the character and identity of a wine. The golden rule is to closely monitor the maturation process of a wine in order to taste it at the right moment. This is also what makes oenology so charming and interesting. Enjoy your tasting!