By David Setley
“Tannins” is a wine term I am frequently asked to explain to folks who come into the store. I’ve found that even wine enthusiasts who have enjoyed wine for many years find the term to be confusing. So, let’s take a deeper dive into the topic.
Scientifically speaking, tannins are a phenolic compound. According to sciencedirect.com, phenolic compounds are among the most common chemicals found in many plants throughout the world. They are one of the most significant secondary metabolites (the most important components behind the health benefits and medicinal properties of plants) and are largely responsible for the antioxidant attributed to many “superfoods.”
Tannins are present in the skins of wine grapes. After harvesting the grapes, the winemaking process continues with what is commonly called the crushing of the grapes. I know we all just had an image of Lucille Ball stomping grapes in a gigantic barrel in Italy, right? In modern winemaking, Lucille stays on the sidelines as crushing is accomplished by a machine that very gently squeezes the grapes enough to separate the juice, referred to as “must” in wine-speak, from the skins, seeds, and stems, called “pomace”.
Fun wine fact: The overwhelming majority of wine grapes have clear juice, regardless of whether the grape itself is red or white. Without the skins having contact with the juice during fermentation, most wines would be white. In other words, if the winemaker’s goal is to produce a white wine, he or she removes the skins before the juice continues to ferment. The exceptions are grapes referred to as “teinturier grapes.” Alicante Bouschet, a grape from Portugal, is one such exception. See why this varietal is a favorite of mine by trying the Cartuxa Evora Tinto Reserva 2017. This outstanding red wine from the Alentejo region of Portugal is 70% Alicante Bouschet and 30% Aragonez and is, in my experience, the best example of a wine made from a teinturier grape.
If a red wine is the winemaker’s objective, the “must” and the “pomace” remain in contact during maceration. Simply stated, maceration is a soaking process where the tannins are gradually transferred from the skins to the juice. The juice will take on the color, the flavor, and the antioxidant qualities discussed above. The duration of maceration depends on how tannic the winemaker wants the wine to be. For most red wines, maceration can be as short as a week or two, and as long as a month or so. As you may have guessed, rosé wine is accomplished by allowing the skins to macerate for a very short time in the juice, resulting in the familiar pink color. In general, the longer the skins have contact with the juice, the higher the concentration of tannins. The thickness of the grape skin can also play a part in this. It is all part of the science and artistry of winemaking.
In addition to color, tannins affect wine by adding to the flavor and mouthfeel of the wine. Prior to fermentation, wine grape juice is sweet. In fermentation, yeast consumes much of the sugar and turns it into alcohol and carbon dioxide. The sugar that remains is called residual sugar and is a major determinant of how sweet or dry the wine is. Tannins have a slightly bitter taste that, together with remaining residual sugar, adds to the complexity of red wine. Bitterness may not sound appealing. However, think of how tea, coffee, and dark chocolate have significant bitter components but are still considered delicious. It is the same for wines. Finally, tannins give wines an astringent effect, commonly referred to as dryness. As mentioned, tannins are a phenolic compound, which binds proteins. The saliva on your tongue and in your mouth is full of proteins that the tannins bind, making your tongue, gums and palate feel dry. This is why high-tannin wines pair well with steak. The tannic effect counters the fattiness of the meat.
If you would like to experience the tannic effect of wine for yourself, buy a bottle of Pinot Noir (a relatively low-tannin red wine), a bottle of Cabernet Sauvignon (a relatively high-tannin wine), and a bottle of Syrah/Shiraz. A couple of Pinot Noir options to consider would be the Domaine Valéry Le P’tit Renaudat from France, or the Montinore Estate Pinot Noir from Willamette Valley, Oregon. For the Cabernet Sauvignon, how about a Cab-based blend from Bordeaux, such as the Daou Cabernet Sauvignon from Paso Robles, California? For a Shiraz, try the 19 Crimes-Shiraz from Australia or the Truchard – Syrah 2021 from California. Pour a tasting of each and observe them side-by-side. Notice the variations in darkness and opacity of the wine from the least to the most tannic. Take a couple of sips of each in order of least to most tannic and notice the astringent effect of the more tannic wines. And, of course, enjoy the wine!
Do tannins cause headaches? According to Harvard Health Publishing Online, maybe, for those who are particularly sensitive to tannins, but for the majority, no. The most likely suspect is the alcohol. Alcohol can cause blood vessels to dilate, thus causing headaches. If you are someone who gets headaches when drinking red wine, drink a glass of water for each glass of wine to help alleviate the problem.
David Setley is enjoying his retirement from higher education as a wine educator and certified sommelier at Passion Vines in Somers Point, New Jersey.
