Greywacke is a New Zealand winery based in Marlborough, the country's largest and most established wine region. Founded by Kevin Judd, who previously served as winemaker at Cloudy Bay for many years, Greywacke focuses on producing wines that express the distinctive character of Marlborough's varied terroir.

Marlborough is renowned primarily for its Sauvignon Blanc, which benefits from the region's cool climate, long sunshine hours, and diverse soil types ranging from river stones to clay. The region's location at the northern tip of New Zealand's South Island creates ideal conditions for aromatic white wines, with significant diurnal temperature variation helping preserve acidity and develop complex flavors. Pinot Noir has also gained recognition in Marlborough's cooler sub-regions.

Greywacke's current range includes Sauvignon Blanc and Chardonnay among the white wines, along with Pinot Noir. The winery produces both regular and "Wild" versions of their Sauvignon Blanc, suggesting different winemaking approaches or vineyard selections within their portfolio.

Marlborough occupies the northeastern tip of New Zealand's South Island, centered around the Wairau and Awatere valleys. The region became New Zealand's largest wine-producing area following the planting of its first commercial vineyards in the 1970s. Marlborough accounts for approximately two-thirds of New Zealand's total wine production, transforming the country's international wine reputation within a few decades.

The region experiences a cool maritime climate with significant diurnal temperature variation, particularly in the Wairau Valley where morning fog often gives way to sunny afternoons. Marlborough's diverse soils range from young alluvial gravels near river beds to older clay-based soils on hillside terraces. The Wairau Valley typically produces wines with more immediate fruit character, while the cooler Awatere Valley tends to yield wines with greater minerality and structure.

Sauvignon Blanc dominates Marlborough's plantings and defines its global identity, characterized by intense tropical fruit flavors, herbaceous notes, and bright acidity. The region's distinctive style of Sauvignon Blanc, with its combination of passionfruit, gooseberry, and bell pepper characteristics, differs markedly from Loire Valley expressions of the same grape. Pinot Noir and Chardonnay represent the region's other significant varieties, with Pinot Noir particularly successful in the cooler sites and Chardonnay showing both oaked and unoaked expressions depending on producer philosophy.