As we continue to learn more about the different components of wine, there is one important aspect we can’t ignore: the captivating presence of tannins. These compounds, nestled within the grape skins, seeds, and stems, weave a tapestry of flavors and textures that define the very essence of wine. Tannins are the silent architects, shaping not only the taste but also the structure and aging potential of each bottle. As we uncork the secrets behind tannins in wine, we’ll unravel the complexities that make red wines bold and robust, exploring how these polyphenolic wonders contribute to the character and allure of our favorite vintages.
Before we can get into the importance of tannins in winemaking, we need to look into what they actually are and where they come from. Whether you are a wine enthusiast or just drink it occasionally, chances are you have heard about tannins. The term “tannin” comes from the Latin word for tanner and they are naturally occurring polyphenols found in plants, seeds, bark, wood, leaves, and fruit skins. And for those non-science people, polyphenols are macromolecules made of phenols which are complex bonds of oxygen and hydrogen molecules.
While tannins are mostly found in red wine, due to the aging being done in oak barrels, they can also be found in white wines – especially those that are aged in oak barrels, like Barrel-Fermented Chardonnay, or those that ferment on their skins.
As mentioned above, tannins in wine primarily come from the skin, seeds and the stems of the grapes. During the maceration process, sugar is processed and alcohol is produced which causes color and tannin to be released into the wine. The alcohol that is produced dissolves more tannins than water and therefore, “the longer the skins and pips macerate during and after fermentation the more tannic the final wine will be.”
Since white and rosé wines are fermented without contact to the other grape components, experts explain that the tannin levels will be lower in these wines than in reds. But, if a winemaker decides to ferment a white wine on extended skin and pip contact, the tannin levels have a possibility of being as significant as in red wine. The wood vessels in which wine is fermented and/or aged in can also impart tannins into the wine.
The development of tannins begins in the vineyard. Scientists explain that once a fruit set happens, tannins start accumulating. Any of the tannins present in the skins protect the grapes from the sun. The more light that reaches the surface of the grape, the more tannins the skins produce. Grapes grown in higher-altitude vineyards tend to yield more intensely tannic wines.
Tannin levels vary in each grape variety. For example, Tannat and Nebbiolo, are known for having especially high levels of tannins and these wines can require years of aging before they’re ready to enjoy.
One factor that can affect the tannin type in the fruit is the condition in the vineyard. Cooler climates, like the Leelanau Peninsula, tend to yield more aggressive tannins – more astringent and less polymerized at the time of harvest. Fruit grown in warmer climates and from warmer vintages will have more developed, softened, and polymerized tannins. The same goes for fruit that is harvested at a later time.
In addition to the vineyard characteristics and practices, tannins can be affected by techniques used in the cellar. The techniques affect more than just the amount of tannins – but also the quality of the tannins. Unlike color, tannins require alcohol for extraction – especially from the seeds – and the rate in which the extraction increases happens as alcohol concentration rises during the fermentation stage.
Tannin extraction can be increased with frequent punchdowns, warmer fermentation temperatures, extended maceration, and the use of enzymes. Since there are several factors that can impact the extractability between grape varieties and ripeness levels over different vintages, winemakers have no easy way to anticipate what a wine’s total phenolic content “will be based on a particular grape’s total phenolic content.
Levels in Wines
According to VinePair, darker-hued wines tend to show heightened levels of tannins because of the extended maceration of the grapes’ skins, stems, and seeds. Some examples of this being true are Cabernet Sauvignon, Syrah/Shiraz, Sangiovese, Tannat, and Tempranillo. One exception is Nebbiolo, which makes pale-colored red wines.
Pinot Noir, Gamay, and Grenache are varieties that typically show lower tannin levels due to the thinner grape skins on the fruit.
Even though white wines normally don’t macerate with their skins, there are ways to extract tannins if the winemaker so chooses to produce a white wine with some. One example is orange wine. Orange wine is made with white grapes but goes through the same process as red wine and is kept in contact with their skins during fermentation causing a higher level of tannins. The same is true for darker hued rosé wines due to the extended period of maceration with the skins.
Exploring the intricate world of wine tannins unveils a fascinating journey through the senses. As we’ve delved into the origins, types, and effects of tannins in wines, it becomes evident that these compounds play a crucial role in shaping the wine-drinking experience. From the astringency that tantalizes our taste buds to the subtle complexities that linger in each sip, tannins contribute to the rich tapestry of flavors found in different varieties. Whether you’re a seasoned wine enthusiast or a newcomer to the world of oenology, understanding and appreciating the influence of tannins adds depth to the enjoyment of this timeless beverage.