It is very difficult to make high-quality consommé soup. Usually, only food experts and experienced chefs prepare consommé, as it involves a very meticulous process. Consommé soup is regarded as one of the most appreciated soups in the world, extending well beyond French cuisine, from which it derived.
Consommé is always a clear soup, as it uses as a central ingredient either flavored stock or bouillon. Consommé soup also incorporates egg or egg whites, mirepoix and finely ground meats, normally lean beef or veal. Mirepoix is a French term denoting the combination of onions, carrots and celery. These three ingredients are sometimes called "aromatics." Mirepoix is what gives consommé soup its flavors and aroma.
Simmering is the main process involved in preparing consommé soup, and it is one of the processes that distinguishes consommé from other soups. During simmering, the stock or bouillon is clarified through a tedious process of fining involving an egg or egg whites. The simmering, combined with frequent stirring, causes impurities to rise to the surface of the liquid. The acid in the tomatoes also helps to purify the soup. As the soup simmers, solids begin to conceal at the surface, forming what is called a "raft" due to the proteins in the egg. As soon as solids begin to congeal, the heat is reduced and the soup simmers at a lower heat for another 45 minutes to an hour until it has reached desired flavor.
Simmering removes a lot of impurities, but the consommé still must be purified further. The soup is passed through a filter that removes more impurities. Then, all the fat is skimmed from the surface with a cheesecloth. Sometimes, a final step in the purification of the soup is refrigeration, which draws out remaining fat that can be skimmed off with the cheesecloth. However, refrigeration requires the preparer to reheat the soup before serving.
Consommé soup is very expensive to prepare, which is why it is normally only served in fine dining restaurants. One small bowl (approximately 8 fl. oz.) of consommé requires almost a pound of meat, which is clarified and reduced during simmering and purification. Further, the soup can require an expert or experienced chef to attend to it very carefully for several hours. The cost of ingredients and labor account for the soup's price.