Most soups do not require any artificial color adjustments. A guiding rule is that where possible allow the natural colors of the vegetables used in the production to determine the final color of the soup.
There are a few types of soups that may need some color adjustment, namely consommés, creams, veloutés and those with a brown roux base.
(a) Consommés. Generally the problem is that the consommé is too pale in color in which case gravy browning may be added very carefully, a little at a time. The addition of too much coloring agent is very difficult to rectify and is not always possible. It is far better to serve a very pale consommé type soup than one that has been ruined by adding too much color.
(b) Creams and veloutés. Generally the problem is that these soups are too dark in color but this may be rectified by adding additional liaison. If these soups are too light in color then additional egg yolks may be added to the velouté type soup and additional basic béchamel to the cream type soups.
(c) Brown roux-based soups. Generally the problem is that these soups are too pale in color. This can be rectified by the addition of tomato purée and gravy browning. Where the soup is too dark in color the color adjustment is most difficult, costly and time consuming as it will need to be added to a lighter colored base soup.