German Mustard or Senf is similar to the French Bordeaux mustard. German mustard if traditionally dark in colour, although some are lighter in colour, sweet-sour to taste and flavoured with herbs and spices. The main centre for making German mustard is Düsseldorf. German mustard is mild, so is best eaten with cold meats and spicy German sausages. There are sweeter mustards for eating white sausages, Weißwurst.
Dowell, P., Bailey, A. (1980) The Book of Ingredients, Dorling Kindersley. ISBN 0718119150.