White wine vinegar is a clear, pale straw-coloured acid made by souring white wine: acetic-acid bacteria oxidise the wine's alcohol into acetic acid, turning it sharp. Brighter and more neutral than cider or malt vinegar yet softer and rounder than harsh distilled vinegar, it keeps a light grapey, floral fruitiness that flatters delicate cooking. It is the classic acid for beurre blanc and hollandaise, for pickling and for clean, crisp vinaigrettes.