I must confess that I had been drinking wine, with quite an interest, before I paid any attention to anything other than the flavour of a wine. And when I started working in the trade and heard people going on about tannin and acidity I was kinda bemused as to what they were talking about. It was only after a tasting with Jane Ferrari of Yalumba that I began to understand what tannin and acidity were in terms of wines.
So what the hell is Tannin?
The tannins in a wine are derived from the pips, skins and stalks. They are really important if a wine is intended to age, as they are a natural preservative. The tannins give structure to the wine. They can be sensed by a furring of the mouth, or puckering of the gums, like when you drink cold tea (which also has tannins as its made of leaves). Tannins can also be found in chocolate, nuts and berries among other food stuffs.
Tannins are of more importance in the ageing of red wines rather than white, as they tend not to occur to the same extent if at all in whites. The tannins act as a preservative, they fade over the years, and the simple fruit flavours have time to develop into the more complex flavours that are found in aged wines. A level of tannins that is sufficient to provide structure, but not so obvious as to dominate the palate, is the ideal when a wine is ready for drinking. For this reason tannins are still important in red wines not intended for long ageing, as they give structure to these wines. Tannins have different qualities, and may be described as harsh (especially in a wine drunk too young), soft (eg. Beaujolais), stalky, chalky, and so on.