Gravy Browning is a colouring agent that enhances the appearance of brown sauces and gravies. Gravy browning is usually just colours - caramel, salt and water. Sometimes flavours are added, e.g. hydrolized vegetable protein and MSG. The mixture is boiled, filtered and bottled.
Use with caution, adding only enough to get the right colour as it can have a metallic taste.
Dowell, P., Bailey, A. (1980) The Book of Ingredients, Dorling Kindersley. ISBN 0718119150.