After the primary fermentation the yeast cells have converted around eighty percent of the sugars into alcohol and carbon dioxide.
Then the brew is pumped to 160 hectolitre conditioning tanks to slowly mature at a temperature of 10° Celsius. There the yeast converts the remaining sugar into alcohol and carbon dioxide. The conditioning tanks are airtight so that the carbon dioxide dissolves directly into the beer.
The Westmalle Dubbel matures for two weeks, the Tripel for around five. At the end of this period the beer clarifies in a natural, unforced way. The yeast and proteins sink spontaneously to the bottom of the tank. The beer is now ready for filtering.
