Boon Geuze Mariage Parfait is a traditional unsweetened, unfiltered Oude Geuze from Lembeek. Once a year, the Boon Brewery makes a mixture of different large barrels of 3-year-old Lambic, which is specially brewed and has a high degree of fermentation. After a maturation of 6 to 12 months in the bottle, this gives a special “Oude Geuze” of no less than 8 Vol. % Alc.