Alfredo Maestro vineyards are located within the Ribera del Duero, preferring not to participate in the D.O.(Denominación de Origen ), so the wines are Vino de la Tierra de Castillo y León. Using hand harvested grapes with only organic and biodynamic practices and no sulphur added in the winery or the vineyard, his unfiltered wines are the epitome of minimal intervention natural wines.

He started making wine in the late 1990's when he planted his first vineyard near his native town. From the beginning he set out to farm organically, but in the early 2000s he started questioning why he was using chemicals to make the finished wine. So he set about eliminating them and then in 2003, he began making wine without any additives.

Over the past few years, he has been seeking out neglected vineyards around the Ribera del Duero and Madrid to convert to his ways. As a result of his production, he has emerged as one of the most dynamic and well known natural winemakers in Spain, making rustic but fun bottles like the lively El Marciano Garnacha.