Part of the intrigue of fine wine is the way it matures and develops in the bottle. The art of evaluating young wines with regard to their potential longevity is one of the most difficult to master. Even in the best cases, there are always surprises -- wines that seemed insubstantial in youth that blossom with age, or those that impress at the outset but have little to show when they reach supposed maturity. Variations among newly-made wines are due to a multitude of factors, but generally fall into three major categories -- the vineyard site, the climate during the growing year, and the winemaker’s decisions. Only after the grapes are harvested, the wine and winemaking decisions made, can the bottle ageing process begin.
Let us first consider some of the potential pitfalls along the path to making an ageable wine, then we’ll explore the bottle ageing phenomenon in greater detail. The vineyard site is key to creating wines with ageing potential. The best vineyards, when properly managed, yield the best grapes and thence -- again with proper winemaking care -- the best wines. All winelovers know, however, that improper vineyard care or bad winemaking practices can result in truly disappointing wines from potentially excellent vineyard sources.
Those in the business of selling wine are often asked if a wine is from a "good" vintage. It would be nice if a simple yes or no answer would suffice, but more that a nod of the head is required to assess the quality of a given harvest. Those seeking simplicity can turn to any number of vintage charts that will give a broad overall rating of vintages from particular regions. The degree of accuracy in such broad-based assessments, however, is inherently limited. Any given harvest may be superb for one maker's wine while only average or poor for others.
The goal of vintners throughout the world is to harvest a crop of healthy, perfectly ripe grapes that will yield aromatic, flavorful, and well-balanced wines. Many climatic factors affect a finished wine, starting early in the year and stretching throughout the growing season. Early season frosts can devastate a crop by destroying the flowers of the grapevine before pollination. Rain at the time of flowering and pollination can also have a dramatic impact on the amount of fruit vines will produce. Excessively cool or hot temperatures at any time in the growing season can affect the flowering of the vines or the rate at which the grapes ripen. Excessive rainfall or humidity can wreak havoc with vine and fruit health and hailstorms can capriciously destroy a harvest. Insect-borne vine diseases can also attack vineyards during a growing season and have a significant effect on the quality and/or quantity of the harvest. The weeks before the picking of the grapes are a critical time. Ideally, the weather is warm, sunny and dry and the grapes are picked at optimum ripeness. Rain at harvest can swell the grapes with water, resulting in pleasant, but soft and dilute wines. Excessive humidity and heat can encourage the growth of molds, resulting in rotten grapes that will taint a wine unless they are sorted out and discarded. Extreme heat alone can accelerate the ripening of grapes to the point where pickers cannot harvest them fast enough. The result here is overripe, excessively alcoholic wines. Cold weather at harvest can retard ripening and result in tart, thin wines — and these are just some of the problems vintners face.
Suppose the winemaker receives a relatively normal harvest of grapes. He or she can now ply the vintner’s magic. Many factors, such as the type of tannins, the acidity level, the grapes used and blends thereof, can significantly alter the ageability of this fermented beverage. The winemaker becomes an artist painting a canvas with each decision crucial to the lasting impression. The winemaker’s response to all the potential problems becomes more and more evident as the wines age. Flaws that seem minor in a wine’s youth become magnified with increasing age. Subtle imbalances can reach amazing degrees of awkwardness. In any winegrowing region, however, there are winemakers more adept at dealing with some or all of the viticultural and vinification problems they face. We are constantly surprised at the quality of the best wines produced in so-called "off" vintages. Astute wine buyers will benefit by giving these unheralded vintages a close look, since the prices of the wines are frequently far lower than those of more highly-praised harvests.
What really happens once the cork is inserted in the bottle? History has proven that a corked glass bottle is a perfect hermetically sealed container. Oxygen is the catalyst for the ageing process, but too much oxygen accelerates ageing at too rapid a pace. The cork is a pliable material that will maintain an impermeable seal if it remains compressed and moist in the neck of the bottle. Problems occur when that seal is broken and outside oxygen comes in contact with the liquid inside. The actual molecular changes are not yet fully understood, but there are a multitude of chemical reactions necessary before the "aged wine bouquet" is evident. Some reactions that are known result in: reduction in fruitiness and varietal aromas, softening of tannin astringency in red wines, and the gradual decrease in color intensity, from purple/black to brown/red in red wines and from yellow/green to yellow/brown in white wines. The most noticeable of these molecular changes during the ageing process is the accumulation of sediment in the bottle. This can occur in both red and white wines, but is primarily seen in reds. Temperature of storage can influence the rate of change dramatically, the cooler the better, with 50°F being optimal. Is it really necessary to age every bottle you buy? Heck no! Over 90% of wines are consumed within 3 hours of purchase. Let your own palate be your guide rather than a simple vintage assessment that, by its nature, can only give a rough approximation of quality. Historically, certain regions and grape varieties improve greatly with some time spent lying around in a cool, damp cellar. Those bottlings make their presence known in the marketplace by their ever-increasing prices. No bottle requires aging, however, many bottles will handle it gracefully and rewardingly. It’s all up to your personal preference. Try an experiment by purchasing 3 bottles of the same wine and open a bottle at 1 month intervals. Do you notice a difference? Then try 3 months between tastings, then 6 months, 1 year... At what point do you perceive a difference in the aroma, the flavor? The enjoyment of this fermented beverage can be such an amazing and rewarding pursuit. Look at it as a journey, with a new discovery at every junction. Enjoy the trip, not just the destination.