http://en.wikipedia.org/wiki/Wit_beer

.... White beer (Dutch : witbier, French : bière blanche) is a barley/wheat beer brewed mainly in Belgium, although there are also examples in the Netherlands and elsewhere. It is a descendant from those Medieval beers which were not brewed with hops, but instead flavoured and preserved with a blend of spices and other plants referred to as gruut. It therefore still uses gruut, although nowadays the gruut consists mainly of coriander, orange and hops. ...