Aside from the four noble varieties, which of the following is an important white variety in Alsace?

Pinot Blanc is indeed an important white variety in Alsace. This region is known for producing a range of high-quality white wines, and Pinot Blanc plays a significant role in that diversity. It is appreciated for its versatility and often features a round mouthfeel with flavors of green apple, pear, and subtle florals. Additionally, it is used in various styles, including still and sparkling wines.

The prominence of Pinot Blanc in Alsace is supported by the region's unique terroir, which combines geology, climate, and traditional vinification practices, allowing the variety to express its character fully. This makes it a key component of the Alsace wine landscape, complementing the more famous noble varieties such as Riesling, Gewürztraminer, Pinot Gris, and Muscat.

The other varieties mentioned are less significant in Alsace. Roussanne is primarily associated with the Rhône Valley, Semillon is mainly grown in regions like Bordeaux and Australia, and Chenin Blanc is most prominent in the Loire Valley, particularly Vouvray.