Aging wine in oak came about by accident.

A few hundred years ago, before the mass production of glass bottles, wine was sold in bulk and transported in wooden barrels. Merchants, the majority in England, would then resell the wine, keeping it in barrels the whole time.

Wooden barrels were easy to move by rolling them, easy to control their movement because of the convex shape of the barrel, and wood was relatively inexpensive.

In the course of transporting wine across the English Channel, the wine would transform.

A startling discovery came when people noticed the difference in the color, flavor and texture of the wine after it had spent time in contact with the wood. The wine also lasted longer before spoiling when left to sit inside a barrel and take in the tannins from the wood.

Before long, wine producers realized the benefits of making oak contact with the wine part of their normal winemaking regimen.

Oak's inherent characteristics make it the obvious choice among wood species. It is durable yet can be bent into shape when heated. It has good anti-leaking properties, yet it allows microscopic amounts of air through it over time to enhance the wine's structure without spoiling it.

When heated to high temperatures, the wood produces chemical compounds that elicit flavors of vanilla, almond, cloves and spice, all of which complement many wines, to one extent or another.

Today, wine is not only aged in oak but sometimes also fermented in oak.

With a winemaker's skill, the seamless integration of wine and wood can create an attractive taste and aroma.

The drawback to oak in wine comes when the flavors from the wood overtake those of the fruit. Not only does this hide the true varietal character of the grape, but it also creates clashes when trying to pair the wine with food.

Red wines that almost always are aged in oak include cabernet sauvignon, merlot (and blends of them), zinfandel, syrah, pinot noir and sangiovese.

The most popular white wine to age in a barrel is chardonnay, while other white wines may or may not be, depending on the grape and style of the winemaker.

— Len Napolitano lives in Central Coast wine country and believes the more you understand wine, the more you enjoy it. He is certified in wine by the Society of Wine Educators, Wine & Spirits Education Trust, and Chicago Wine School and gains knowledge from his frequent contact with California winemakers. More information is on his Web site, at http://www.wineology.com. Send your questions about wine to wineologist@earthlink.net or by mail to Len Napolitano in care of the Ventura County Star, P.O. Box 6006, Camarillo, CA 93011. Wineology is a registered trademark of Len Napolitano.