Still remember I once spend a few weeks in the library around the 90's reading about the process of winemaking, from harvesting, pressing, fermenting, aging...etc. During the fermenting process, there's two chemical affecting the character and colour of the wine, of course the chemical process is much more complicated. This essay'll just introduce the Tannins, and Anthocyanins in wine.
Tannins present in grape seeds, stems and skin. When grapes are pressed, tannins end up in the fermenting wine. Red wine contains a greater quantity of tannins than white wine due to extended skin contact during winemaking. However, it is not entirely uncommon, to discover tannins in white wine. Such tannins likely originate in wooden barrels used to ferment oak-aged Chardonnay. These polymeric phenol concentrations in red wines range from 100 mg/L in very light wines to more than 1000 mg/L in very tannic wines. Tannins, treated the right way, allow wine to age gracefully. Winemakers have discovered that tannins prevent wine from oxidizing prematurely, maintain color in red wine and can even impart an additional sensory dimension in wine - a little something called mouthfeel. When using words to describe the tannins in wine, you could probably use: Dusty, Gripping ,Mature & Round, Young & Slightly Astringent, Silky, Soft & Integrated...etc. Hopefully, you won't taste rough, bark-like & leathery in your wine.
Besides chlorophyll, anthocyanins are probably the most important group of visible plant pigments. It also acts as an antioxidant, therefore, we heard so much health effect of red wine, blah, blah, blah...But this chemical is what give red wine it's color, it will interact with tannins, giving wine's colour a higher stability. Polymerization of anthocyanins happens most rapidly during fermentation and maceration, but the process continues through the life of a wine. As wines age, a greater proportion of their anthocyanin content is polymerized. Like the other wine polymers, precipitation may also remove anthocyanin polymers from wine.
It usually take 2-3 years for wine to reach it's first ripe period, which is a good time to enjoy new wines, with more brilliant color and characters, and freshness of the fruit. For aged red wines, it usually reach it's second peak from 10 years and onward. Some wine even acheive their peak around 20-22 years or so. At this time, some part of the pigment will break down, leaving the wine with an orangie-reddish colour. But further on after the peak period, the wine will only diminish it's qualities. The peak of wine varies with the variety of grapes, and sometimes to a particular batch in a particular year. But of course, a bottle of crap is always crap, a bottle of aged crap isn't any better than when it's young, so don't get too excited when you see a bottle of aged wine. Also because even a good bottle of wine can be ruined easily with wrong handling & holding: temperature, humidity, infestation...etc.
