How can you tell if your wine has tannin or not? Well, all wines have tannins, but not all of them contain in the same concentrations. Tannins are the pigment that gives wine its color, and more importantly, they grant it its heaviness, warmth and body.
Red wines contain tannins in high concentrations. It's this compound what gives wines more complexity and fuller body. With ageing, tannin becomes even more saturated, and it even helps preserve the wine's quality and taste for longer.
White wines, on the other hand, contain little tannin. This condition makes them light, crisp and unsuitable for long periods of ageing - which is why white wines are normally aged for 12 months or less.
Wine makers obtain both white wines and red wines from the very same grape. The step of the process in which a wine-to-be is defined as a white wine or a red wine is at the moment of crushing.
Because tannins are stored in the grapevines stems, and in the fruit's skins and seeds; in the process of making white wines, these elements are separated from the must after crushing.
During crushing, some tannin is extracted into the grape juice, and since its quantity is minimal, they resulting drink is yellowish-amber in color.
Knowing that white wines contain tannins in low concentrations, and that red whites present high levels of this component, we can assume that a wine's color darkens the more tannins are present. Next time you have a glass of wine, take a look at its color. Is it light yellow, or darker amber? A translucent brick red, or a rich red-purple? The more color your wine has, the more tannin it will contain - and the fuller it's body.
White wines and red wines also differ in their production during the process of fermentation. Since tannins are developed at warm temperatures, red wines are fermented at higher temperatures than whites. Also, since the warmth speeds up fermentation, red wines are treated for a shorter time.
White wines are fermented under highly controlled temperatures in order to halt the development of tannins. To make up for the slower yeast activity, the fermentation process is longer than that of reds.
Another element that intensifies the saturation of tannins in a wine is oak. Oak is generally used for the ageing of red wines, including some whites such as chardonnay.
Chardonnays are favored amongst white wines are they simulate the dryness and body of a red wine, while being refreshing and crisp at the same time. These qualities (dryness and full body) are granted by the use of oak, and the effect that it has in the natural tannins that are present in the wine.