Not surprisingly, a Quad is usually stronger in flavor and ABV than its Tripel and Dubbel cousins. Alcohol varies, but is usually at or over 10% ABV.
Generally dark amber to dark brown, the Quad style is known for a strong and complex flavor profile. Flavor is heavily malt influenced, with hints of dark fruit, brown sugar and molasses, as well as fruity and spicy yeast notes. Hop flavors are present to help counteract the malt sweetness, but generally low. Alcohol is almost always noticeable.
Best served warm, at 58-61 degrees, in a beer snifter, stemmed tulip glass, or a chalice.