Quadrupel is the brand name of a strong seasonal beer La Trappe Quadrupel brewed by De Koningshoeven Brewery in the Netherlands, the only Trappist brewing abbey not in Belgium. In other countries, particularly the United States, 'quadrupel' or 'quad' may refer to an especially strong style of dark ale, with a characteristic spicy, ripe fruit flavor.[1][2][3][4][5][6][7][8]
A quadrupel is intended to be stronger than a Tripel, so the ABV strength will be 10% or more. Beyond that, there is little agreement on the status of Quadrupel as a style.[9] Beer writer Tim Webb notes that similar beers are also called 'Grand Cru' in Belgium and Holland.[10]