Champagne is prized above all for its elegance. At first glance, it might seem that the richness and potentially oaky flavors of barrels would be ill-suited to Champagne's delicate character.

In recent years, however, there has been a marked increase in the number of Champagne producers experimenting with wood for both fermentation and aging. While some are over-oaked, there are also genuinely successful Champagnes that gain complexity and character from wood without losing balance and finesse.

"A barrel can bring a roundness and a fruitiness to a wine," says Laurent Champs of Vilmart & Cie. "It completes the structure of the grapes. The wood is never there to mask anything. It's there to give a touch of subtleness, to help the wine express its roundness and puissance. It creates something more complex."

This increase in oak-fermented or oak-aged Champagnes can be connected to an increased focus on Champagne's qualities as a wine, prior to undergoing the processes that make it effervescent.

Champagne is made from an initial blend of base wines that are low in alcohol, high in acidity and have relatively little aroma. The second fermentation in bottle and subsequent aging on the lees contribute so much to the final wine that conventional wisdom often asserts that neutral base wines create the finest Champagnes. (In reality, this has never been true. If neutrality were really the goal, why pay extra for distinctive grand cru grapes?)

Today, more and more cutting-edge Champenois winemakers are seeking base wines with greater character and personality - relying on more conscientious viticulture, increased natural ripeness, and more individual lots made from different parcels. As the base wines have grown more complex, it seems only natural that some winemakers would experiment with wood.

Before the mid-20th century, all Champagnes were made in wooden barrels. These barrels were traditionally used for many years, and were fairly neutral in character. But barrels are expensive and labor-intensive, and in the 1950s and 1960s most producers began using large tanks. Initially these were often vats made of cement or enameled steel, though stainless steel later became the industry standard.

Steel had many advantages, the most important of which is precise temperature control. However, stainless steel also creates a more anaerobic environment than a porous wooden vessel. Less exposure to oxygen alters the character of the wine. Many winemakers welcome this effect. Yet a few sought a return to the more ample character achieved with barrels.

A few houses have never stopped using wood. One of these is Alfred Gratien, which continues to vinify nearly all of its wines in old, wooden barrels.

"The idea is not to make the wines taste oaky," says Nicolas Jaeger, Gratien's cellar master, "but to give them more structure and finesse, and greater length."

For Jaeger, as for most Champenois winemakers who work with oak, the primary benefit of a barrel is micro-oxygenation: a gentle, controlled oxidation through the barrel's permeable walls. This process not only contributes to the development of flavors; it also influences a wine's structure.

"A wine made in tank is more sleek and angular," says Eric Rodez, a grower in Ambonnay who vinifies about 80 percent of his production in barrels. "Fermenting in wood changes the texture of the wine, giving it another dimension. It also gives a wine more depth and makes it more resistant to oxidation, because of the micro-oxygenation."

Nearly all Champagne producers who work with wood, from Bollinger to Krug to Vilmart, use it for precisely this reason. But sometimes a deftly applied touch of flavor from barrels can be used to enhance a Champagne. Taittinger, for example, uses a small percentage (no more than 5 percent) of oak-aged wine to add complexity to its prestige cuvée, Comtes de Champagne.

"We use the wood for its toast and vanillin notes," says cellarmaster Loïc Dupont, "not for micro-oxygenation like some other houses."

Making the wine in wood can be awkward, particularly in small barrels, where the ratio of wood to wine is high. A wine needs to have a certain richness and body to be able to benefit from oak without being dominated by it, and Champagne with overt flavors of oak tends to be heavy and clumsy.

The finest examples use wood without imparting an obtrusive oakiness. So many producers choose to blend a small percentage of barrel-fermented wine with wine from the tank. Those who use new oak will usually use just a barrel or two in a blend. Even those who vinify entirely in wood, such as Jacques Selosse or Vilmart & Cie., will employ only a small amount of new oak.

So the oak vs. tank decision is a crucial one. Not all base wines benefit from wood.

"This is the No. 1 question I have to answer during the harvest," says Benoît Tarlant, who barrel-ferments about two-thirds of the production at his family's grower estate. But Tarlant points out that wood allows some wines, like his Cuvee Louis, to express themselves more fully.

"The question is: Can the barrel bring out something in the wine that wouldn't be achieved if the wine were made in tank? It's like opening a door."