cider
Spanish cider, mainly from Asturias and the Basque Country: dry, tart, usually cloudy and still.
Spanish sidra natural is a dry, distinctly sour, still cider, closer to traditional farmhouse cider than to sweet commercial brands. It can be found in Spanish delis, well-stocked wine shops or by mail order; note that in North America plain "cider" often means unfermented apple juice, so look for hard cider.
Substitute:
Dry hard cider or cidre brut works well in cooking; a sweeter cider makes the dish rounder and less sharp, which a splash of cider vinegar partly corrects.