What is the primary red grape variety used in the central Loire, especially in Sancerre?

The primary red grape variety used in the central Loire, particularly in the Sancerre region, is indeed Pinot Noir. This grape is well-suited to the cool climate and diverse terroirs of the area, resulting in wines that often exhibit fresh, red fruit flavors, along with herbaceous and earthy notes.

In Sancerre, Pinot Noir benefits from the region's chalky soils, which help to express the grape’s inherent characteristics while also contributing to the wine’s structure and minerality. The wines made from this variety in Sancerre tend to be elegant and aromatic, showcasing the classic profiles associated with Pinot Noir.

The other grape varieties mentioned are not typically associated with Sancerre or the central Loire. Merlot and Cabernet Sauvignon are primarily grown in Bordeaux and are not prominent in the Loire Valley. Tannat is used mainly in the southwest of France and is known for its robust tannins, making it unsuitable for the style of wines commonly produced in Sancerre. Thus, Pinot Noir stands out as the quintessential grape of the region.