Why do red wines improve with age? Simply put, it is all about tannins. Tannins are a family of natural organic compounds that are found in grape skins, seeds, and stems. They are the key to giving wine their great aging potential, by slowing oxidation.
Since they are an excellent antioxidant and natural preservative, the process of extracting their benefits is a very important part of red winemaking. With white wine, the grape juice is pressed off the skins prior to fermentation. Red wine is fermented with the grape solids, thus facilitating the natural tannin extraction.
Winemakers monitor and manage the tannin extraction by manipulating the solids (typically just the skins) which rise to the top and form a cap in the vat. Ultimately, the cap will be removed when the wine is determined to have extracted the required amount. This process begins during maceration and continues through fermentation and bottling.
The tannins of a young red wine are very bitter. Over time, tannin compounds join with each other and with other molecules to form long polymers. When these polymers grow larger, they settle out of the wine, making it softer and more pleasantly astringent than bitter.
Once bottled, wine has very little exposure to oxygen (just the airspace at the top). Shortly thereafter, the tannins will have absorbed the remaining oxygen in the bottle and the process becomes anaerobic (taking place without oxygen). Now this process slows down big-time. At this point, the wine's components interact and continue to evolve and link together. Over a period of time, the wine develops increasingly complex aromas and flavors. In addition, it shifts in color from purplish to brick red.
Keep the bottles stored at a uniform temperature (55-65 degrees Fahrenheit or 13-18 Celsius). If it is warmer, you will speed up the aging process. Experience has proven that cooler temperatures slow the aging process and results in better wine complexity.
Watch out for temperature fluctuation. When wine warms it expands, and when cooled it contracts. If so, the corks can move in or out accordingly. This can allow small amounts of oxygen into the bottle. This oxygen entering the bottle can spoil the wine.
While most white wines are intended for drinking within two to three years after the vintage date, many red wines perform well and even improve with age. Tannins are there to help you out, just do not make their work harder by not storing your bottle at its desired constant temperature.
Contributor: WineDefintions Staff Writer