Decanting Wine: The Science, The Myth and The Realty Recently a wine club member called to reorder a case, an Italian Barbera from the Artisan Series. He asked if many people had reordered the wine, and I answered no. He said that he wasn’t surprised. He and his wife had sat down to dinner and were unimpressed by the wine. A telephone call interrupted their meal for a half hour, and when they returned to the table and their glasses, they were astounded by the wine’s transformation. The Barbera, which at first was banal, was now brimming with berry flavors and aromas and had a silky texture. What could possibly have happened during the half hour that the wine sat in the glass?

The simple answer is that the wine was allowed to “breathe.” Exposed to air for that half hour, it was able to release its flavors and aromas. The formal method for bringing about this transformation is to decant the wine before serving, transferring it from its original bottle into a decanter, although the process is not without controversy.

The undisputed advantage of decanting pertains to older wines that over time have thrown sediment in the bottle. Carefully transferring the wine to another container while the sediment remains in the original bottle separates the unpleasant sediment from the wine. Another undisputed aspect of decanting wine, whether old or young, is simply that a beautiful decanter made with clear glass is an esthetic pleasure that enhances both the wine and the table.

The controversy centers around whether or not decanting wine and thus aerating it as it transfers from one container to another really benefits the taste, supposedly releasing aromas and fruit flavors and softening tannins through oxidation and evaporation. Most people in and out of the trade think it does although the science, at least what exists, says not or not exactly.

When winemakers taste professionally, they swirl wine in a glass and sniff it first before sipping, because we perceive only sweet sour, bitter, and salt with the taste buds on our tongues and every other flavor with the nerves in our noses. Swirling the wine sets its molecules in motion so that aromas can be more easily inhaled and then identified by our brains. Likewise, decanting a wine will set molecules in motion as does swirling it in a glass although some argue that exposing the wine to air over a prolonged period will dissipate delicate aromas, especially those of older wines.

While aerating wine for at least a short period can noticeably improve flavor, making it smoother is debatable. The primary reason that winemakers age red wine in barrels is that wood is slightly porous and allows the wine to undergo a carefully controlled oxidation over many months. Oxygen promotes the polymerization of tannins, which links shorter molecules into chains that feel smoother on the tongue. In older wines, these chains will become heavy enough to actually fall out of solution and create sediment in the bottle. But the process occurs over many months or years, not within the hour that wine might be exposed to oxygen in a glass or a decanter.

But what can happen within an hour is that preservative sulfur compounds, added during the winemaking process, can evaporate. Yeasty components and carbon dioxide in white wine can also dissipate. Without these extraneous elements, intrinsic fruit flavors become more apparent. Red wine will also more quickly reach room temperature after decanting and feel smoother in the mouth than at lower temperatures.

So if you are not in the habit of decanting wine, should you start? I say yes, at least when you have the time and want to enjoy a given wine at its very best and especially if you think a wine is not as good as it should be.