When it comes to a wine's ability to be aged, both tannin and acidity play a role. Tannins were described last time as having compounds that act as natural preservatives in wine.  The natural acids in the juice of the grape also help to preserve a wine for better aging.

Acids are common in fruits and give them their refreshing qualities. Fruits like apples, lemons, limes, and grapefruit are acidic and have that crisp, fresh, mouth-watering quality. Grapes too have acids that are highest before they ripen and are reduced as they ripen.

Acids can give wines a crisp, tart, refreshing and zesty flavor such as you might experience when drinking a glass of lemonade. And, the acids produce additional saliva which leave you with a mouth-watering affect immediately after consuming. This is common in white wines such as Sauvignon Blanc, Pinot Grigio and Riesling.

Along with preserving a wine and giving it a fresh crisp flavor, acids also help to 'balance' wines.  The balance is typically between acids, sugars, tannin and alcohol. If any one of these traits is too high or too low the wine will be un-balanced and just taste wrong. Too much sugar results in a syrupy sweet wine. Too much alcohol gives a hot burning sensation in your mouth and throat. And too high of a tannin level results in a harsh mouth drying and puckering sensation.  If a wine has too much acid it will seem sharp and if it lacks acids it can seem dull, boring, flat or 'flabby' as the wine world calls it. So balance is important.

The balance of acids is especially evident in red wines where you don't get the crisp and zesty flavors. Red wines are typically less acidic than white wines and the higher tannin and alcohol act to significantly reduce the acidic sensation and produce the 'smooth' mouth-feel sensations most often associated with Cabernet Sauvignon, Merlot and Zinfandels.

To put the levels of acids in perspective, we must briefly revisit chemistry and pH levels. Water is neutral from an acidity perspective and has a pH of 7 on a scale of 1 to 14, with the most acidic items having a pH of 1 (a seemingly backwards scale). Typically coffee is thought to be highly acidic but it comes in around a pH of 5-6. Lemonade on the other hand has a pH typically around 3. Wines will range in between with a pH of 4 for some red wines and go to a pH around 3 for some types of white wines.

As just another way of describing balance in beverages, the balance of acids and sugars is strongly evident in lemonade and cola drinks.  They are both higher in acidity than all wines but have a tremendous amount of sugar that acts to balance out the acid and create enjoyable drinks.

So all of these traits need to be in balance. And acids play an important role in this balancing act. So whether it be a crisp and zesty Riesling or a smooth Cabernet Sauvignon, know that acids are important to the overall flavor and the ability of a wine to age.  Cheers!

Behind the Cork™ Wine of the Week - Justin Sauvignon Blanc ($13)

This Sauvignon Blanc from Paso Robles is a great example of a crisp, zesty and refreshing wine. The winery describes this wine as having fruit elements of guava and pineapple with subtle orange peel, and fresh herbal notes including chamomile flower.

It is dry, crisp and refreshing with lemon, green apple, white peach and guava. The finish is bright and clean, with a slight mineral texture.  This is an excellent value and worth searching out.