Thickening Agents

 THICKENING AGENTS

Thickening agents give body, consistency, and palatability when used. They also improve the nutritive value of the sauce. Flavored liquids are thickened and converted into soups, sauces, gravies, and curries etc. In other words binding agents are used to transform the stocks into sauces.

There are various types of thickening agents, which are used in modern day cookery. They are as follows:

·                  Starches

·                  Flour

·                  Roux

·                  Beurre Manie

·                  Fruit and Vegetable Puree

·                  Egg yolk

·                  Cream

·                  Butter

·                  Blood

 A… Starches:

Starches derived from roots and vegetables are among the oldest and the most versatile thickener for sauces. They are efficient and inexpensive and that they can be used without imparting flavour of their own.

 Starches should be combined with liquid and heated to almost boiling temperature to be effective. Some starches are purer than others. Cornstarch, arrowroot starch, and potato starch are almost pure starches and produces shiny sauces, whereas flour contains protein, which gives a mat appearance to the sauces.

Cornstarch:

Of the purified starches, cornstarch is the most familiar. They should be used at the last minute for the thickening of the sauces and the cooking liquid that are being served. When it is cooked for long time then it looses its thickening power. Cornstarch is first mixed in water and then used to thicken the sauces and soups.

Arrowroot:

Arrowroot is the best of the purified starches because it remains stable even after prolonged cooking. It is used the same way as cornstarch. 

Potato starch:

 Although potato starch is one of the first starches to be used in French cooking, it has never been popular as a sauce thickener. It is used the same way as the cornstarch and like cornstarch it tends to break down after prolonged exposure to heat.

B…Flour:

In western cooking, flour has long been the most popular thickener for the sauces. It can be used in several ways. Although flour has largely been replaced in recent years by other thickeners. It is still the appropriate choice for many country style and regional dishes. Liquid in which flour is to be added must be degreased before the flour is incorporated. Flour binds with lamb and holds it in suspension throughout the liquid, making it difficult to skim. Result is a greasy, indigestible sauce with a muddy texture and flavour.

C…Roux:

The most common method of thickening liquids with flour is to prepare a roux, by cooking the flour with an equal weight of butter. This enhances the flavour of the flour and eliminates the lumps. Because flour contains proteins and other compounds that imparts flavor, sauces thickened with roux are usually skimmed for thirty minutes once they have been brought to simmer to eliminate the impurities. Although the stock is skimmed before the roux is added, further the sauce is skimmed to eliminate the butter, impurities in the flour.

There are three types of roux:

·       White roux

·       Blonde roux

·       Brown roux

White roux: it is prepared by cooking flour and clarified butter for approx. 5 minutes over slow heat and stirring constantly with a wooden spoon. It is used for Béchamel sauce and thick soups.

Blond roux  :Is made from fresh butter and flour. The preparation of butter and flour are the same as for white roux. It is made more rapidly and should be made at the last before using. Its color should be pale gold. It is used for volute sauce and for some soups.

Brown roux: cooking flour in bouillon fat in the oven, gently and for a long time, removing from time to time to stir, makes it. This roux should be of light brown color. It is used for brown sauce and demiglace.

HOW TO COMBINE ROUX AND LIQUID:

1.                 When you have a hot roux, combining it with a liquid is a two-step process. In step 1, you add part of your liquid, cold to the hot roux, blending it in with a whisk. In step 2 you blend in the rest of the liquid hot.

2.                 When you have cold roux, you can combine it with hot liquid, over heat, by blending it in with a whisk a little at a time.

Do not try to combine hot roux with hot liquid and cold roux with cold roux.

  

D…BEURRE MANIE: 

Like roux, beurre manie contains equal part by weight of butter and flour. It differs from roux because it is not cooked and is usually added at the end of the sauce’s cooking rather than at the beginning. It is most often used to thicken stews at the end of the cooking when the braising liquid is too thin.

The beurre manie should be added little by little in boiling stock whisking continuously so that lumps do not form.  Unlike roux the beurre manie should not be cooked once the sauce is thickened otherwise the sauce will a floury taste. One of the peculiarities of flour is that develops a strong floury taste after two minutes of coking that begins to disappear as the cooking progresses. 

E …FRUIT AND VEGETABLE PUREE

Some times fruit and vegetable puree are used in thickening sauces and soups. The puree soups are the best example of the same 

 F…Egg Yolk

Because they thicken sauces in several ways, egg yolks are versatile liason. They provide base for emulsified sauces, such as mayonnaise and hollandaise, and are used in conjunction with cream to finish the cooking liquid of poached meats and fish.  Not only form emulsion of fat and liquid but also combines with air so that they be used for sabayon sauce.

Sauces containing should not be boiled unless they contain flour, which stabilizes them. When combining egg yolk with liquids, be sure to combine some of the liquid separately before returning the mixture to the saucepan. If the egg yolks are added directly into the hot liquid then they are liable to coagulate as soon as they get in contact with the heat.

 G… Cream

In recent years thickened cream has replaced roux as the thickener, becoming base for white sauces. 

Precaution should be taken in reducing cream. Quick whisk should be given to the cream otherwise they become granular and may break. Always use large saucepan, three times the volume of the cream otherwise flames from the sides can discolor the cream.

Whenever cream is used, as a thickener in a wine based sauce, are sure to reduce the wine otherwise they giving an unpleasant flavour.   Cream used in conjunction with egg yolk, butter, and flour gives a better result.

H…Butter

 When butter is whisked into a hot liquid, it forms an emulsion, similar to the action of egg yolk. The milk solids and proteins contained in the butter acts as emulsifier and give butter sauce their sheen and consistency. Because the milk solids in the butter are what maintain the emulsion, sauces and cooking liquids cannot be thickened with clarified butter. In fact cold butter is proffered to hot butter in thickening of the sauces.

I… Blood

Blood has long been used in cooking to finish sauces for braised or roasted game, poultry, or rabbit. Blood not only deepens the sauces flavour but also acts as a thickener. The blood must be mixed with a little amount of vinegar to avoid coagulation.