The Quetsche Tilquin à l’ancienne (6.4% alc / vol) is a spontaneous fermentation beer obtained from the fermentation of destoned fresh purple plums (variety Prune de Namur or Quetsche véritable d’Alsace, close to the Damson) in a blend of 1, 2 and 3 years old lambics for a period of 4 months.