A beer of spontaneous fermentation, Riesling was made by fermenting fruit that had already been used once. Riesling grapes were fermented for a period of 4 months in a blend of 80% 1 year old Meerts and 20% of a blend of different 2 year old lambics. Meerts (or March Beer) is a low strength lambic, which was originally produced with the weaker wort obtained from the rinsing of the grains. Unfiltered and unpasteurized, they are refermented in the bottle.