Tannin, or tannic acid, is found in red wine. But it’s also infrequently found in a white wine like Chardonnay if the wine in question is kept in oak for an extended period of time. Otherwise, tannin is derived from grape skins and oak barrels in which red wines is often aged. It’s worth noting that the juice from most red grapes is clear. There are exceptions to the rule and those rare red grapes that have pink juice are called teinturier. Color then in red wine comes from the skins. That’s no surprise given there are hundreds of phenolic compounds—including tannin—found in the skins of red grapes.

Tannin tastes bitter and feels astringent on the palate. Many, including me, perceive tannin from grape skins in the front of the mouth while tannin from oak aging is tasted and felt in the back of the mouth, on the tongue, and soft palate. Wines such as Barolo and Barbaresco, both made from the Nebbiolo grape, show both grape and oak tannins. These same wines are also high in acidity and bone dry. In other words, they’re grownup wines that need food.

Tannin also enters the winemaking equation if carbonic maceration or whole cluster fermentation is involved. With either, stems are part fermentation and green, stemmy tannin part of the profile of the wine.

Otherwise, tannin in red wine dries out the palate, which is not a surprise. Think about tanning leather. It’s the same process. Tannin is a preservative as well. It’s in part responsible for red wine having the potential to age. Tannin is also found in other beverages and foods. Coffee, tea, and chocolate all have a fair amount of tannin. Leave a tea bag in a cup of just-boiled water for 20 minutes and the tea will be undrinkably bitter. The same goes for strong coffee, which is why many reach for cream and sugar to take the edge off the inherent bitterness. Baker’s chocolate is also bitter from tannin, hence why most chocolate has sugar added. In the food world, chicory and radicchio are both high in tannin and therefore bitter in taste.

Over time, tannin molecules in wine form chains. As a wine gets older, or more tannin is added through various means, the chains of molecules get longer. We perceive a wine with long chains of tannin molecules as being “smooth” on the palate. For us in the industry, that’s important. When asked in a survey for their favorite red wine descriptor, over 7,000 of 10,000 New York restaurant diners said smooth.

As mentioned, longer chains of tannin molecules form over time as a wine ages in barrel or in the bottle. However, winemakers can do any number of things to speed up the process. A red wine can be fermented in barrel, in which case it takes on more tannin earlier during primary fermentation and malolactic/secondary fermentation. Oak chips—which are considerably less expensive than barrels–can also be added to the wine as it ages, raising the tannin level. Otherwise, adding powdered tannin is now a standard industry practice for red winemaking. Specifically, various kinds of powdered tannins like those pictured above—all naturally derived from grapes—can be added up to a half dozen times during the winemaking process. In fact, powdered tannin is one of the biggest sellers for Scott Laboratories, the largest California wine industry supplier.

Is there an issue with adding powdered tannin to red wine? Personally, I think not. It’s a winemaker’s prerogative to shape the texture of the wine according to their preference. They’re also adding something to the wine that’s naturally derived from grapes. It’s like salting a dish when cooking. One adds salt bit by bit from the beginning until just before serving as needed.

One’s individual tolerance of tannin is unique. That also goes for the other structural elements in wine (acidity, alcohol, and phenolic bitterness). But it’s especially true with tannin. Some avoid red wine altogether because of sensitivity to tannin. Others complain that drinking red wine gives them headaches. The cause of those headaches could be anything from being dehydrated when drinking to reacting to the histamines in a red wine. With the first, drinking plenty of water is the remedy. For the second, taking an anti-histamine before enjoying a glass of red wine often does the trick. However, more often than not, over-consumption tends to be the problem with headaches and red wine. That said, some people are again naturally sensitive to tannins in red wine and therefore avoid them.

Some cultures seem to have a higher overall threshold for tannin than others. I remember teaching an MS Introductory Course for the first time in Hong Kong in 2008. During the first tasting I was struck by how skewed the perception of tannin was on the part of the students. They underestimated the tannin level with both red wines. As the class went on, it seemed as if no red wine was high in tannin, including the Barbaresco we used in one of the tastings. Then it struck me how, as a culture, the Chinese tend to drink tea from the time they’re small kids. And they grow up drinking a naturally tannic beverage and in doing so may become immune to the bitterness/astringency over time. Which may explain why the students were challenged to accurately assess the level of tannin in any of the red wines being tasted. It may also be why we saw diners in restaurants sipping young tannic Bordeaux rouge as they enjoyed oysters on the half shelf and other shellfish. To us in the west, that combination would be like a train wreck in the mouth. 

Tannic red wines need time in bottle. In the olden days, one would establish a home cellar for just that reason—to age certain wines under the right conditions with the intent of being able to enjoy them years later when they reached maturity. Few people now have the space or wherewithal for a cellar. Otherwise, one can always purchase an older bottle from a retailer. But the high price will reflect someone having cellared it for years. Hopefully, the wine will have been stored under the right conditions.

No surprise that most ageable red wines are now enjoyed long before maturity. Which necessitates one of several strategies. First, consider opening and decanting the wine at least an hour before drinking. If it’s a tannic red like the aforementioned Barolo, I’d even consider pouring the wine in a larger red wine glass and letting it sit for at least an hour. However, be sure to cover the glass with a piece of paper or clean cloth to prevent fruit flies from getting to the wine before you do. If a fruit fly manages to get into the wine, it creates a film on the surface as well as an odd taste.

Aside from decanting and pre-pouring, matching the right dish with a young tannic red is important. Live game tends to be a good overall pairing. Just kidding. Actually, the magic combination of protein, fat, and salt takes the edge off a young tannic wine. With beef, a cut like a ribeye or Porterhouse is best as they tend to be well-marbled with higher fat content. Lean cuts of beef like a filet go better with older, less tannic wines. Lamb or vitamin P (pork) also generally work well with younger, more tannic reds. Finally, more intense cooking methods like grilling also help to match the intensity of a young tannic wine.

Tannin aside, balance in any wine is still key. The important components that comprise balance are fruit and acidity in any wine with the addition of tannin for red wine. Likewise, any red wine needs to have a concentration of fruit matched by higher acidity and framed by tannin. A red wine that’s not well-balanced tends to lack fruit, is possibly over-oaked, or it’s just too tannic. However, there are exceptions. Sometimes context comes into play in the form of a certain red wine that has a long track record of not only being tannic when young (think Barolo), and needs a long time in the cellar. It’s complicated, just like a lot of things in the wine world. Which is why we read and taste. And why we drink. À votre santé!