Wine is often referred to as being tannin, or having soft tannins. But what exactly are tannins, and what role do they play in wine? Read on and let the Club Baron de Lestac explain. The word tannin comes from the Gaulish word “tann,” meaning oak. These phenolic compounds are crucially important as they influence the colour, character and taste of wine.
Tannins are a natural part of wine: they are found in the skin, pips and stems of grapes, and are extracted by macerating the grape juice along with the solid parts. In this way, the wine acquires texture and structure. Tannins also have an impact on colour and its stability, and provide protection from certain wine faults, keeping oxidation at bay and eliminating reductive notes.
Tannins found in grape skins are considered to be the most noble as they are the most ripe. Those present in the pips and stems are greener and bring the mouth-puckering, drying sensation known as astringency. These particles combine with proteins found in saliva to create a solid cluster, literally draining the saliva. Wine growers choose to destem their fruit (or not), depending on the desired level of tannins. The oak barrels in which wines are aged can also be a source of tannins (hence the origin of the term). Although tannins are generally found in red wine, they can be found in whites that have undergone a period of barrel ageing. New barrels impart more tannins, but the quality and origin of the wood, and the time and intensity of its toast are also factors.
Different grape varieties have different amounts of tannin. The thicker the skin, the richer it is in tannins and colour pigment. For example, Merlot, Cabernet Sauvignon and Malbec have higher levels of these phenolic compounds. This is why Bordeaux wines often have good ageing potential, with tannins that soften over the years, losing their astringency and becoming more silky. Pinot Noir, Gamay and Cinsault have less tannins, thus wines made from these grapes are easy to drink young. Although the choice of grape is important, it is not the only criteria: vinification style is also a factor. The producer has an influence on the extraction of tannins, according to various steps in the winemaking process: length of maceration time, of course, but also punching down and pumping over. The former consists of pushing the cap of grape skins down into the juice, while the latter means pumping the juice up over the top of the cap. By mastering these steps the producer achieves the desired level of tannins in the wine, and an ideal balance.