MYTH: Wines taste better when allowed to “breathe” and get “smoother” the longer they are open.
IMPLICATION: All wine should have the cork removed long before consumption and the longer the better.
ORIGIN: The only substance other than grapes traditionally added to make wine is sulfur, which prevents the wine from oxidizing (spoiling). In the traditional application of sulfur, experience was often more of a factor than science and excess frequently left wines stinking of sulfur dioxide (burnt match), hydrogen sulfide (rotten egg), or mercaptan (skunk). In young wines, these stenches often are volatile and not chemically bound in solution, thus some aeration can alleviate the problem. If not removed prior to bottling, however, the sulfur compounds can bind over time with other elements and become harder if not impossible to remove. Another basis for breathing is that wine seems to get “smoother” over the course of a meal or overnight.
REALITY: Simply removing the cork to allow the wine to “breathe” has no effect whatsoever.
APPLICATION: The waiter, sommelier, or “expert” is wasting your time by simply removing the cork without decanting the bottle. It has been scientifically proven that the narrow space of the bottle neck where the wine can contact air is inadequate to produce any change within a period of even 24 hours, let alone a few minutes.
MY CONTENTIONS: I first became suspect of the value of “breathing” in 1974, when, in wine appreciation classes, we drank two different bottles of 1899 (not a misprint) Sierra Madre Zinfandel. These 75-year-old bottles were throwing a very silty sediment and so we decanted them to remove it. The first bottle had a wonderful, heady, cigar-box nose when we pulled the cork, but by the end of the 30 seconds or so we took to decant it, the aroma had almost entirely vanished. So, when we opened the second bottle, we beckoned everyone gather around the decanting table to enjoy the fleeting sensation.
Modern methods of wine hygiene and low-sulfur production techniques have greatly reduced the occurrence of sulfur-compound stinks in wine, rendering aeration at serving moot. The phenomenon of wines “changing” over the course of a dinner to become perceptively “smoother” is a function more of physiology than chemistry. In the time window of one or two hours during which it is consumed, the wine does not change so much as the wine taster changes. That first taste of wine includes the very slightly painful sensations of heat from the alcohols and pucker from the acids and tannins. As the wine is consumed, not only does the palate adapt, becoming more tolerant and less sensitive to these stimuli, but the tastebuds and brain also become more and more anesthetized from the effects of ethanol. As the initial shock dissipates, the taster becomes aware of more subtle complexities. The wine seems to taste smoother and more complex, when it is in fact the taster’s sensitivities that undergo the most rapid and greatest degree of change. (see Taste: A User’s Manual)
As far as (especially) big red wines tasting smoother the day after opening, I suspect most of the smoothness comes from the very slight evaporation and reduction in ethanol, the most volatile component, but this at the expense of the aromas which have dissipated. Before you argue against this point, try an experiment (with no deviation or prejudice). It requires two bottles of the same wine, preferably from the same case, two identical decanters, masking tape, a pen, and an assistant (although this exercise is more instructive and fun with additional tasters). The morning of your tasting, open and decant one bottle. Do not open the other bottle. Out of sight, the assistant uses the pen and masking tape to mark each bottle and its corresponding decanter (with a random mark, such as X and O) to keep track. Several hours later, but immediately before tasting and out of sight of the taster(s), he decants the second bottle. The wines are then immediately poured “blind” for the tasters to decide which bottle (decanter) smells and tastes best. Most of the time, the just-opened bottle wins. The results, furthermore, will be consistent, whether using young or aged wines, whether white or red, and whether the tasters are experienced or not.
MY ADVICE: If you truly place great value in allowing your wines to aerate, simply pulling corks won’t do it. Decant the wine, regardless of an absence of sediment. However, the older the bottle of wine, the more brief the aroma window, so gather your friends around to appreciate the fragrances as you decant to remove any sediment and then pour that wine at once!
(Post Script: the unpleasant, musty smell that comes from the presence of TCA, often referred to as “corkiness”, unfortunately will not dissipate, no matter how long the wine is open, nor how violent the decanting.)