Sour Grapes: The Acid in Your Wine

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Our bi-monthly wine tasting group met the other day and looked at Russian River Pinot Noir, tasting around 18 wines, including a very good Burgundian ringer. The tasting was packed with about 25 people in attendance. In the first flight there were six wines and four out of the six had noticeably elevated volatile acidities.

Volatile acids consist mainly of acetic acid, which is easily recognized aromatically as vinegar, and, to a lesser extent, ethyl acetate, which smells of nail polish remover. These are important components of wine. In small doses they can lift wines aromatically and make fruit more present in the nose. For example, low-level volatile acidity can elevate a simplistic cherry aroma, adding dimension and depth, creating a backdrop of blackberry, black currant and chocolate.

They can create such aromatic complexity that It can be like going from a one dimensional world to a five dimensional one with a little age of Aquarius thrown into the mix for aromatic complexity. In limited quantities, they are the plastic surgeons of the wine world, and can give the wine an acid lift, making a wine seem fresher, fuller, and more lively

Volatile acids are most important in warm regions where wines seem clumsy without an obvious acidic lift. When they are bad, they are very bad, and when volatile acids get away from the winemaker they ruin a wine and can render it undrinkable.

The smell of vinegar can be so pungent that it almost feels like it is wrenching out our nose hairs by the root. And the smell of ethyl acetate makes a wine seem so chemical that you can feel as if you are being waterboarded in a nail salon (maybe this appeals to some people).

The mouth feel of the wine becomes sour and thin. The tannins of the wine become so bitter-tasting that the experience can be similar to having a root canal performed by a dentist who suffers from acute halitosis.

The smell of ethyl acetate makes a wine seem so chemical that you can feel as if you are being water boarded in a nail salon.

Wines with greater density or higher sugar or alcohol can balance larger quantities of these acids; think of the classic balance of sweet and sour in Chinese food. Wines such as Port, Sauterne, and Sweet German Wines like Eiswein, Trockenbeernauslese, and Hungarian Tokay can all support larger quantities of volatile acidity than dry wines because of the higher sugar content.

The main culprit in elevated levels of volatile acidity is acetic acid bacteria. Acetic acid bacteria gain a foothold in wine mainly due to winemaker neglect during aging. Because exposure to air fuels their growth it is important that the winemaker tops barrels and tanks, that is, adding wine to fill the vessel so that there is no room for air to enter.

Other than these four wines that had high volatile acidity there was one wine at the tasting that was corked. Corky wine is generally caused by the presence of chloro or bromo anisoles that create a musty, moldy, wet cardboard or damp basement smell. The main culprit is airborne fungi that contaminates corks before they are put into the bottle.

Wineries can also have ambient problems where the corky character is picked up in wines from treated wood products, pesticides, or tainted chlorinated water before it is bottled. Corky wine is the main reason that the French sommelier watches you so closely when he puts the small taste in front of you at the restaurant. If the wine is corked, you can send it back.

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Aaron Pott is founder of a firm that is dedicated to producing wines from different, distinct terroir in the Napa Valley. More

Aaron Pott, a veteran of vineyards in France and California, is founder of a firm that is dedicated to producing wines from different, distinct terroir in the Napa Valley as well as consulting for a limited quantity of notable producers.

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