A roux is a combination of fat and flour, which are cooked together. There are three degrees to which a roux may be cooked(White, blond and brown) and one approach known as ‘continental’ roux style. A boiling liquid should never be added to a hot roux as the result may be lumpy and the person making the sauce may be scalded by the steam produced. If allowed to stand for a time over moderate heat, a sauce made with a roux may become thin due to a chemical change (dextrinisation) in the flour.
This is used for white (béchamel) sauce and soups. Equal quantities of butter and flour are cooked together without colouring for a few minutes, to be a sandy texture. Alternatively, use polyunsaturated vegetable margarine or make a roux with vegetable oil, using equal quantities of oil to flour. This does give a slack roux but enables the liquid to be incorporated easily.
This is used for veloutés, tomato sauce and soups. Equal quantities of butter or vegetable oil and flour are cooked for a little longer than a white roux, but without colouring, to a sandy texture.
This was traditionally used for brown (Espagnole) sauce and soups and is slightly browned at the roux-making stage.
This is a very easy and straightforward thickening agent that can be frozen and used as a quick thickener during service or à la minute. Mix equal quantities of flour and vegetable oil together to paste and place in the oven at 140° C. Cook the mixture, mixing it in on itself periodically until a sandy texture is achieved. Remove and allow to cool to room temperature. When it is cool enough to handle, form into a sausage shape using a double layer of filing film. Chill, then freeze.
To use, remove from the freezer and shave a little off the end of the log. Whisk it into the boiling sauce(as the flour is already cooked it is not necessary to add it slowly to prevent lumping as this will not occur). Once the desired thickness has been achieved, pass and serve.