Brewed by the family-owned Brewery Bosteels in Buggenhout, Belgium, Kwak is named after an 18th century innkeeper and brewer, Pauwel Kwak.

As with other Belgian beers, Kwak has a branded glass with its own distinctive shape, yet the Kwak glass has attracted great attention because it is a round-bottomed, hour-glass shaped glass that resembles a stirrup cup or 'yard of ale', which is held upright in a wooden stand―rather like a piece of old scientific apparatus.

Kwak is a dark, warming beer with liquorice-like flavours and a slightly spicy character. The bitterness always remains in the background but in the end emerges delicately.