What Are Tannins in Wine?

When talking about wines, and especially when tasting them, the wine jargon can appear complicated for beginners: viscosity, mouthfeel, light-bodied, heavy-bodied, legs, bouquet…and tannins. The last one often sparks curiosity as it is perhaps one of the most common and important to understand, particularly for beginners.
If you’ve ever sipped a glass of wine that left a dry, astrigent feeling on your tongue, you have experience tannins in action. But tannins are more than just astrigency. Indeed, they play an important role in the structure of the wine, its aging potential, and taste complexity.

So, what are tannins in wine and what do they do?

Understanding Tannins

Tannins are naturally occurring plant-based compounds called polyphenols and exist in many things we eat and drink, such as fruits, tea, and chocolate. These polyphenols compounds play an important defensive role in plants, acting as a deterrent to herbivores.
In the realm of wine, these reside in the skins, seeds and stems of grapes. During the winemaking process, the grapes are pressed, the juice extracted. That’s where it becomes interesting as the role of the grape skins in the winemaking process will either result in a white, red, rosé or orange wine (yes, orange! see A Guide to Orange Wine).
When making white wine, the juice is left to ferment without the grape skins. For red wines on the other hand, the grape skins soak with the juice (a process called maceration). The longer this contact, the more tannins end up in the wine, imparting more color and making it more astringent. Moreover, the oak barrels used for aging also impart tannins, adding to complexity and the aging potential of the wine.

In brief, the longer grape skins, seeds and stems soak with the juice, the more tannins they release.

Note: If you macerate white grapes skin with the juice, they will impart an amber, orange color to the wine. This is how orange wine is made. For rosé, the skins of red grapes macerate with the juice for a much shorter period of time compared to red wine. This is enough to tint the wine, but not enough to give it a heavier body.

How Tannins Affect Wine

Understanding tannins is more than just understanding how wine is made, or why does it have an astrigent taste. Tannins are the silent but crucial players, especially in the world of red wine.

Structure

Tannins provide the foundation for a red wine’s structure. And by structure, we’re referring to the full picture you get when tasting wine. Tannins add weight and body to wine, creating a pleasant textural contrast to the acidity and fruit flavors. Imagine a symphony – tannins provide the bassline that grounds the melody.

Texture

Does the wine feel silky? Smooth? Velvety? Or very light? This is what is often referred as “mouthfeel” or the feeling you experience in your mouth when tasting wine. And tannins are the main contributors to the mouthfeel.

Taste

The drying, bitter feeling you get when drinking red wine comes from tannins. Tannins are complex molecules with a particular fondness for proteins, especially those found in your saliva. When you take a sip of tannic wine, these tannins latch onto the proteins in your saliva, causing them to clump together. This creates a drying or puckering sensation on your tongue. This astringency balances the sweetness and acidity of the wine, creating a more rounded and harmonious overall experience.

Aging Potential

 Tannins act as antioxidants, protecting the wine from spoilage and oxidation. This is the reason wine red wines, in particular with high tannins such as Cabernet Sauvignon, age so well. Oppositely, white wines, which contain lesser tannins do not age well and have a shorter lifespan.
Moreover, as the wine ages, tannins polymerize (link together), becoming smoother and less astringent. This allows the other flavors in the wine to evolve and develop, creating a more complex drinking experience.

Do Tannins Cause Headaches?

People with sensitivity or intolerance to tannins, can experience headaches when consuming them, even if in small quantities. Some of the other common symptoms include stomach ache or bowel irritation.
If you experience such symptoms when eating food that contain tannins, you’ll most likely experience them too when drinking wine. The most common foods include:

• coffee
• tea
• dark chocolate
• most berries
• nuts (almonds, peanuts, walnuts…)

Can Tannins Be Removed or Reduced?

While winemakers cannot completely remove tannins from wine, they can reduce them by a process called “fining” which involves adding a fining agent (usually protein-based like gelatin or egg whites) to the wine. The tannins bind with the fining agent, which then forms a sediment that settles at the bottom of the tank. After racking (transferring the wine without the sediment), the wine has lower tannin content.
This is not a common practice as it comes with certain drawbacks. By removing the unwanted particles, the fining agents can also remove desirable flavor compounds and aroma molecules present in the wine. This can lead to a more homogenized and less interesting taste profile. Moreover, some fining agents, like egg whites or casein, can pose a risk to people with allergies to those specific substances. Winemakers are required to disclose the use of certain fining agents, but not all. And from a environmental-conscious perspective, the production of some fining agents, like isinglass derived from fish bladders, can raise concerns about sustainability and potential environmental impact.

Reducing Tannins

If you are sometimes bothered by the intense taste of tannins, there are some easy and natural ways not to remove them but make them more enjoyable.

Decanting
Letting a high-tannin wine breathe for some time (through decanting) can help soften the tannins slightly by allowing them to interact with oxygen.

Serving Temperature
Serving a red wine slightly chilled can make the tannins feel less pronounced. Experiment with different temperatures to find your sweet spot.

Food Pairing
Pairing high-tannin wines with rich, fatty foods like grilled steak or stews can soften the astringency. The fat in the food acts as a buffer, coating your mouth and reducing the perception of tannins.

Tannins: Red Wine vs White Wine

As the white wine production minimizes contact between the grape juice and the skins, seeds, and stems, it results less tannic wines in comparison to red. On top of that, white wine grapes tend to have thinner skins compared to their red counterparts and naturally contain fewer tannins to begin with.

However, there are some white wines or wines produced from white grapes that are known for higher tannin content.

Oaked White Wines
Certain white wine are aged in oak barrels and can pick up some tannins from the oak itself. This can add a touch of structure and complexity to the wine, but the level of tannins will still be much lower than in most red wines. That is the case of an oaked chardonnay that can develop subtle toasty and vanilla notes, along with a hint of tannin from the oak.

Skin Contact White Wine
Some white wines are produced by macerating the juice and grapes skins (skin contact) for a period of. This is the case of orange wines, made from white grapes with extended skin contact, these wines can have a slight tannic grip and an orange hue

Not all red wines are as tannic. Certain wines, depending on grape varietal and style, can display a more or less tannic profile.

What Wines are High in Tannins?

With no surprise, the most tannic wines are reds. Wines with high tannins are often associated with certain grape varieties and regions known for producing bold, full-bodied red wines.

If you are looking for high tannin wines, you can’t go wrong with Cabernet Sauvignon, Nebbiolo, Syrah/Shiraz, Petit Shiraz, Tannat, Montepulciano, Sangiovese, Petit Verdot, Mourvèdre. These wines often described as bold and grippy, pair well with rich, fatty foods.

For low tannin wines, look for Pinot Noir, Gamay, Barbera, Grenache, German Riesling, Tempranillo, Lambrusco, Cinsault. Lighter-bodied with softer tannins, these wines are known for their fruit-forward character and easy drinkability.