The following terms are used in connection with the making of soups.
Boiling: the cooking of ingredients in a liquid at 100°C. The liquid is visibly moving thus giving rapid cooking.
Clarification: the removal of all impurities from a stock with the object of improving its flavor and clarity as, for example, in consommés.
Gratinated: prepared soup served in an earthenware soup bowl (marmite), the surface of which is layered with dried or toasted slices of bread known as croûtes, sprinkled with Parmesan and Gruyère cheeses and placed under a salamander grill until a golden skin is formed with the cheese (e.g. French Onion Soup).
Infusion: the flavouring of some soups by the addition of various herbs and spices in a muslin bag which is immersed in a little of the hot soup and allowed to give off flavor and aroma but without cooking. The infusion is then added to the bulk of the soup so that it permeates throughout with a little more gentle cooking (e.g. Turtle Soup).
Poaching: almost the same as simmering – the liquid is brought to the boil, then the heat is reduced to stop it boiling but cooking still takes place but at a slower rate.
Puréeing: the pulping of vegetables after cooking to a smooth paste by either passing through a sieve-type soup machine or by means of an electric liquidizer (e.g. Purée of Split Pea Soup).
Reduction: an essence of meat or fish diluted with a liquid so as to produce a soup. The word cullis indicates a strong concentrated essence which can be used to make a soup. Nowadays a purée of shellfish soup (bisque) is made this way.
Simmering: the cooking of an item in a liquid which is just below boiling point so as to give it a gentle boiling action. The temperature would be about 95 °C. Consommés are cooked at this temperature to keep them crystal clear.
Staggered commodity cookery: the identification of those items used in the production of a soup that take the longest to cook and those that take the least time, the aim being to add them in the correct order so that they all become cooked at the same time (e.g. Petite Marmite).
Sweating: the cooking of vegetables in melted butter in a saucepan with a lid on but without coloration, the aim being to extract the flavour from the vegetables and to soften them as in Potage Paysanne.
Thickenings: there are three ways of using thickenings:
(a) using a second or third stage roux with the addition of stock;
(b) the addition of diluted arrowroot or cornflour to boiling liquid;
(c) the addition of rice;
(d) the addition of cream and butter to a completed soup to thicken and enrich it as in a cream type soup (e.g. Cream of Chicken) or the addition of a combination of egg yolks, cream and butter to a completed soup as in a velouté type soup (e.g. Velouté Dame Blanche). This type of thickening is called a liaison.