The mention of tannin in wine often raises the question: what exactly is it, and is it important? Tannin, or tannic acid, is found predominantly in red wine. It is seldom found in white wines, although certain whites, such as Chardonnay, may contain small amounts if they have been aged in oak barrels for an extended period. While this is not common, it is worth mentioning. In most circumstances, however, tannin is derived from the skins of grapes and the oak barrels in which many red wines are aged. It is also worth noting that the juice from most red grapes is actually clear. The colour in red wine comes from the grape skins. This should come as no surprise, given that the skins contain hundreds of phenolic compounds, including tannins.

What Does Tannin Taste Like?

Tannin is often described as bitter and astringent on the palate. Many people perceive grape-derived tannins toward the front of the mouth, while tannins from oak aging are more noticeable toward the back of the mouth, on the tongue, and across the soft palate.
Tannin also enters the winemaking equation when carbonic maceration or whole-cluster fermentation is employed. In both cases, the stems become part of the fermentation process, imparting green, stemmy tannins that contribute to the overall profile of the wine.
One of the defining sensations of tannin in red wine is its drying effect on the palate. This should not be surprising, as tannin acts as a natural preservative and is one of the reasons many red wines have the potential to age gracefully.

Tannin is also found in many other foods and beverages. Tea, coffee, and chocolate all contain significant amounts. If you leave a tea bag in a cup of boiling water for twenty minutes, the tea becomes almost unbearably bitter. The same is true of strong coffee, which is why many people add cream and sugar to soften its inherent bitterness. High-percentage dark chocolate is similarly bitter because of its tannin content, which explains why most chocolate contains added sugar.

Why Does Wine Become Smoother with Age?

Over time, tannin molecules in wine gradually link together to form microscopic chains. As a wine ages—or as additional tannins are introduced through various winemaking techniques—these chains become longer. Wines with longer tannin chains are perceived as smoother and softer on the palate.

This characteristic is particularly important to wine drinkers. When large groups of consumers are asked to describe their favourite style of red wine, the word most frequently used is smooth.

As mentioned earlier, these longer tannin chains naturally develop as wine ages in barrel and bottle. Winemakers, however, can employ a number of techniques to accelerate this process. For example, a red wine may be fermented in barrel, allowing it to absorb more tannin during both primary fermentation and malolactic fermentation. Oak chips, which are considerably less expensive than oak barrels, may also be added during maturation to increase the wine's tannin level.

Individual Sensitivity to Tannin

Each of us has a unique tolerance to tannin, just as we do to the other structural elements in wine, including acidity, alcohol, and phenolic bitterness. This is particularly true with tannin.
There have even been studies examining the effects of tannins from wine and tea on oxidation in the human body. In these studies, wine tannins demonstrated antioxidant properties by resisting oxidation, whereas tea tannins did not to the same degree.

Some people avoid red wine altogether because they are especially sensitive to tannins. Others claim that red wine gives them headaches. The cause, however, may be any number of factors, including dehydration, sensitivity to histamines, or simply the alcohol itself.

Some cultures also appear to have a higher overall tolerance for tannin than others. For example, many people in Chinese culture begin drinking tea as children, becoming accustomed to a naturally tannic beverage throughout their lives. As a result, they often develop a greater tolerance for bitterness and astringency over time.

For this reason, traditional food and wine pairing "rules" should always be viewed through the lens of cultural preferences and eating habits. A culture's long-standing exposure to certain flavours can significantly influence how its people perceive the structural elements found in wine.

Enjoying Young Tannic Wines

Red wines with higher tannin levels generally benefit from bottle age. In the past, many wine enthusiasts maintained home cellars specifically to age wines under ideal conditions, allowing them to reach maturity before being enjoyed. Today, however, fewer people have the space, inclination, or patience to cellar wines for years.

As a result, many age-worthy red wines are consumed long before they reach their peak. If you plan to enjoy a young tannic wine, several strategies can greatly improve the experience.
First, consider opening and decanting the wine at least one hour before serving. If the wine is particularly tannic—such as a young Barolo—you may even wish to pour it into a large red wine glass and allow it to sit for an additional hour before drinking.

Beyond decanting, pairing a young tannic wine with the right food can make a remarkable difference. Foods rich in protein, fat, and salt help soften the perception of tannin, making the wine feel more balanced. Likewise, robust cooking methods such as grilling complement the intensity of youthful, tannic red wines.

The Importance of Balance

With a better understanding of tannin, we would be remiss not to mention what remains the single most important aspect of any great wine: balance.

The principal components of a balanced wine include expressive fruit, vibrant acidity, and, in the case of red wine, well-integrated, smooth tannins. A wine that lacks balance may be deficient in fruit, overly influenced by oak, excessively tannic, or affected by any number of other variables.

Now that we have a greater appreciation for tannin, there is really no reason to be bitter ever again.