Something rather remarkable happens when good wines are allowed to age. Harsh, aggressive tannins soften into mellow succulence; acids, alcohol and fruit harmonize; and an array of aromas flowers into complex, tantalizing bouquets. As wines grow older their colors change as well: the rubies, scarlets, and violets of red wines shift towards orange, brown and brick colors; and the pale straw, green and gold tints of white wines deepen their hues into honey and amber. Also subject to change are aroma and flavor characteristics. Rich notes of spice, caramel, and sweet vanilla from oak barrels emerge in red wines, allied with tertiary nuances of herbs, coffee, tobacco and chocolate, and whites begin to evoke overtones of tropical fruit, nuts and honey.
The vast majority of wines are aged at the vineyard and are released ready for consumption. Crisp acidic whites like Sauvignon Blanc and Pinot Grigio spend only a few months in neutral stainless steel or concrete to preserve their lively fruit and acidic properties (although some like oaked Chardonnay and White Burgundy undergo a secondary fermentation known as malolactic fermentation, which transforms tart malic acid into buttery lactic acid, then spend up to 12 months in new oak barrels). Most reds spend one-to-two years in oak, stainless steel or concrete before bottling (some producers add oak chips, staves or oak extract to these tanks to mimic barrel flavors). Lighter-styled, fruity reds like (most) Rosés and Gamay Beaujolais are released quite soon after production.
But it’s the bigger, more premium reds that truly benefit from further long-term maturation in bottles (cellaring). For a wine to successfully bottle-age it must possess sufficient levels of tannin, acid, residual sugar or alcohol (as well as undergo proper storage) to sustain the rigors of time. High levels of tannins and acids act as preservatives that slow oxidation, as do significant amounts of sugar and alcohol (some sweet dessert wines and high-alcohol fortified wines can age for decades). Highly acidic whites can also survive the cellaring process (although not nearly as long as reds) as can prestige cuvée (vintage-dated) sparkling wines.
Oenology 101: The Basics of All Things Wine
Only about one percent of the world’s wine is suited for long-term aging. The vast majority are crafted for immediate enjoyment, although they can be safely cellared for three to five years after the date (the harvest vintage) on the bottle.
As a general rule, wines priced under $30 will not benefit from aging. Reds with high acidity like Pinot Noir, Zinfandel and Sangiovese can be age-worthy, as can aggressively tannic reds like Cabernet Sauvignon, Syrah and Tempranillo. Briskly acidic whites like Chardonnay, Riesling, Sémillon and Chenin Blanc are candidates, as well.
While over-exposure to oxygen (oxidation) during aging can rob a wine of its fruit characteristics and render it flat and dull (ultimately turning it into vinegar), a small amount of exposure is vital. Introduced either into the fermentation tank or through the porous properties of oak barrels during aging, oxygen unlocks secondary and tertiary flavors and aromas and softens tannins in the finished wine. In addition, a very small amount of oxygen can enter the bottle through the cork stopper, which helps to aid in creating layered complexity and silkiness of tannin