How does an oak barrel influence the aging of wine?

Subtle flavors of oak are passed on to wine as it ages in the barrel. Primarily there are two different types of oak barrels; American oak and the French oak from different regions in France (Limousin, Nevers, Tronçais, etc.), which give varying levels of flavor to the wine, most often described as vanilla. Wine, as it rests in the barrel, goes through subtle chemical changes, resulting in greater complexity and a softening of the harsh tannins and flavors present at the end of fermentation. A barrel essentially does two things: it allows a very slow introduction of oxygen into the wine; and it imparts the character of the wood into the wine. This oak intensity diminishes as a barrel gets older. You usually get 50% of the extract that a barrel has on the first use, 25% the second and less after that; therefore, winemaker’s notes will refer to new oak or old oak, which can indicate the level of the oak found in the wine.

What does malolactic mean and how does it affect the finished wine?
Apart from the primary fermentation of sugar into alcohol, wine undergoes a very important secondary fermentation, called malolactic, in which the malic acid from the grapes converts to lactic acid. Malic acid is that zingy taste in green apples. Lactic acid is the softer acid familiar to us from milk and other dairy products. One effect of this fermentation is to soften the acid balance in the wine. Another is a series of chemical by-products that mute the youthful fruit character in a wine and introduce other, more complex flavors. Almost all red wines and most white wines made by traditional techniques undergo malolactic fermentation naturally, but some winemakers like to prevent it to preserve the freshness of the acidity. Winemakers can also encourage this fermentation by warming up the wine, even by introducing malolactic bacteria.

True or False. It’s okay to chill a red wine.
This statement is basically true, depending of course what the temperature of the wine is just prior to drinking. The notion that red wines should never be chilled is out of date. Today, far too many restaurants and homes serve their red wines so warm that the wine’s aromas practically disappear. The higher the temperature, the more that alcohol tends to dominate the flavor, making it taste harsh and unbalanced. So it’s okay to briefly chill a red wine to help bring out its true characteristics. The general rule of thumb is:

Serve complex red wines between 60-65 degrees F.
Serve complex, dry white wines between 55-60 degrees F.
Serve sweet, and sparkling wines between 54-50 degrees F. Of course wine will warm up eventually to ambient temperature, so it’s okay to initially serve at the bottom end of these brackets.

Originally published in our Gold Wine Club's newsletter, The Wine Press, Taft Street Winery 2006 edition.