Maybe you like German food and dont know what is German Zwieback? Rusk is a bread-like pastry that is cut and roasted conserving sliced until it is dry and crumbly. Where you can buy the German Zwieback is i.e. a German food store like GermanBuy.net. The German Zwieback tea toast manufactured by Brandt, also known as Rusk bread are dry, airy biscuits. Often eaten with coffee, tea or softened with milk to make porridge.