A field blend wine refers to a wine made from two or more grape varieties that are grown together in the same vineyard, harvested at the same time and then co-fermented together. This is in contrast to wines where different grape varieties are grown in separate plots, harvested at different times, and then blended together after individual fermentation.
Historically, field blends were quite common. Before the advent of modern viticulture and winemaking techniques, vineyard owners would plant multiple grape varieties together in a single vineyard so that if one grape variety failed due to disease or adverse weather conditions, others might still survive.
There is a renewed interest in field blends in some wine regions, such as Douro Valley in Portugal, Austria, Alsace, California and South Australia as they can produce unique and characterful wines.