Which grape variety is primarily used for white wines in Rioja DOCa?

Viura is the primary grape variety used for white wines in the Rioja DOCa region. This indigenous grape variety is known for producing wines that typically have a fresh and fruity profile, often with floral notes, making it highly suitable for the climate and terroir of Rioja. Viura wines can range from light and crisp to more complex and age-worthy, especially when subjected to oak aging, which adds layers of flavor and texture.

In addition to its essential role in white wine production, Viura is often blended with other varieties, such as Malvasía, to enhance the aromatic complexity and flavor profile. The versatility of Viura contributes significantly to the distinct character of white wines from Rioja, showcasing the region's potential for quality and diversity.

In contrast, the other grape varieties mentioned do not have a significant presence in Rioja’s white wine production. Chardonnay is more commonly associated with regions like Burgundy and California. Gewürztraminer is primarily grown in cooler climates and is associated with aromatic, off-dry wines. Pinot Grigio, while popular in Italy and increasingly found elsewhere, is not a predominant variety in Rioja's white wine offerings.