What are Tannins in Wine and What Do They Do?

Tannins play a special role in developing your taste for wines. Learn how tannins contribute to a wine's complexity and texture in this article.

If you love wine, there’s a high chance it’s not the first time you’ve encountered the term “tannins.” Whether you’re a full-fledged oenophile, a beginner at winemaking, or a casual drinker, it’s likely that you’ve heard about “tannins” or “tannic” when discussing tasting notes, aroma, or body. 

Whether these compounds give you an intense craving for a glass of wine or a headache, tannins play a significant role in developing your preferences for wine, particularly red wine. But what are they, exactly? In this article, we’ll learn all about tannins and how they affect wine.

What are tannins?

Tannins are astringent- and bitter-tasting polyphenols found abundantly in nature, particularly in the fruits, leaves, bark, and roots of plants such as:

• oak
• pine
• willow
• witch hazel
• maple
• birch

Some high-tannin foods include:

• cranberries
• pomegranate
• cacao/dark chocolate
• cinnamon
• cloves
• sumac
• quince
• tea
• grapes
• … and, of course, wine

What do tannins do?

These natural compounds serve a host of functions, depending on which part of the plant they are concentrated on. By breaking down proteins, tannins in plants can be a deterrent to predators. For instance, they help make unripened fruit unpalatable, discouraging herbivorous appetites. They also act as protection against pathogens and help regulate tissue growth in plants.

Tannins also have a wide range of industrial uses. The word itself comes from the practice of producing leather from the animal hide by using tannins derived from oak trees. Today, they are still used in the leather and wood industries. They have also been used in everything, from food preservation to pharmaceuticals. 

Apart from these, one of the industries with the highest demand for tannins is winemaking. 

Where do tannins come from?

Tannin sources in wine can be: endogenous or purely from grapes, exogenous or from the wood of the barrels used in aging, or added manually.

Tannins in wine are primarily found in the seeds, skins, and stalks of grapes. Red wines tend to have higher tannins because the must or juice sits with the grape skins for a longer period. Meanwhile, white wines are typically fermented with minimal contact with the grape components, resulting in lower tannin content. In this case, tannins are imparted mainly by the type of wood used in the aging process.

What do wine tannins taste like?

A few words often used to describe the taste of tannins are: bitter, astringent, dry, and puckering. Although the exact taste can be hard to pinpoint, if you’re curious, you can conduct a simple taste test by brewing an extra-strong cup of black tea. 

The taste is particularly potent when the tea is allowed to steep longer than the recommended time. The sensation you will have upon tasting—a combination of dryness at the front of your mouth and bitterness on the tongue—is the taste of tannin.

It’s more precise to talk about tannins in terms of texture and touch. The drying sensation has to do with tannins binding with the saliva that lubricates the mouth, stripping its moisture right off. This is why tannic wines are best paired with fatty dishes.

Are tannins bad for you?

Tannins are polyphenols and, thus, have antioxidant properties. They have also been linked to other health benefits such as reducing blood pressure.

Although they are thought to cause headaches or migraines for some people, there hasn’t been any substantial research to maintain that these are caused primarily by tannins. While tannin sensitivity does affect people, “hangover” headaches may also be caused by the other chemicals in wine.

Do tannins help wine age well?

The antioxidant properties of tannins are sought after by winemakers because they help wine age well. Some winemakers even manually add tannin powder because it protects the wine from bacteria. Over time, tannins also contribute to the flavor, aroma, and texture of the wine. As they are polymerized, the wine will lose its harsh astringency, resulting in a smoother wine. 

How do tannins affect wine?

Tannins affect the wine in terms of texture, complexity, and structure. When high-tannin wines are aged longer, it results in a smoother taste. They also give wine structure, contributing to body and balance, and are essential for color stabilization. 

Do all types of wine have tannins?

Tannins exist in all wine varieties, but some have higher concentrations of the compound than others. A good rule of thumb to follow is, the deeper the color, the higher tannin content the wine has. 

Low-tannin wines:

• Pinot noir: This classic, low-tannin red wine is made from thin grape skins and well-known for its light texture.
• Sauvignon Blanc: This popular variety of white wine is known for its zingy, herbal taste with notes of passionfruit. 
• Riesling: Another white, Riesling is an aromatic wine with a range of varieties and notes of green apple, jasmine, and beeswax.
• Tempranillo: Tempranillo is a red wine with a range of varieties, with some having up to medium-level tannins. Tasting notes include tomato, fig, vanilla, and clove.

High-tannin wines:

• Shiraz or Syrah: Shiraz is a full-bodied wine known to have a lot of tannins. It has notes of pepper, berries, and even tobacco and tends to register a heavy sensation in the mouth.
• Cabernet Sauvignon: This age-worthy Bordeaux wine is high in tannins, with notes of black cherry, black currant, and cedar. It’s great to pair with grilled meat.
• Merlot: Another Bordeaux wine, Merlot should be your pick if you want a slightly lighter, velvety red with fruit or cherry flavors with less tannin. It also tends to be sweeter.
• Nebbiolo: Nebbiolo has a lighter aroma but is known to have “grippy tannins.” It pairs perfectly with Asian food and has flavors of anise, cherry, and coffee.

Sampling these and other wine varieties will help you distinguish the differences in complexity and texture brought by tannins.

Enriching your palate

Now that you’re more familiar with tannins, don’t be afraid to be adventurous and try out new varieties. Knowing how tannins work and how they contribute to the quality of wine may encourage you to try making or perfecting your homebrews with a wine making kit.

The world of wine is vast, and understanding tannins will only make the experience all the more enriching. For all things winemaking and more, check out Danny’s Wine And Beer.