White sauce using roux method (Flour (Flour thickens the sauce and is a…
White sauce using roux method
Like flour, milk is a bulk ingredient. It is the main liquid used- gives the sauce it's liquid texture. Without it, the mixture would be solid. Also provides protein and calcium.
Liquids add flavour, moisture, and visual appeal to a dish.
Starches during cooking
However, simply stirring starch and liquid together isn't quite enough to get the liquid to thicken. The catalyst is actually heat. Without it, the starch grains simply sink to the bottom without taking on enough liquid to thicken.
As the liquid heats, its molecules begin to move around very rapidly. These molecules bump into the grains of starch, disrupting their structure enough to cause the granules to take in water. At a certain point during heating, the solution reaches a balance where the starch grains are still mostly intact but have absorbed as much liquid as they can.
All starches work by absorbing water (or other cooking liquid) into individual starch grains. The amount of liquid the particular starch is able to absorb and how concentrated the starch grains are in the liquid affect the thickness of the final dish. At the most extreme, starches can completely set a liquid into a solid, jello-like block!
If you continue heating, the starch will become too disrupted and the grains will actually lose their ability to hold water and thicken a sauce. This is what happens over long cooking or if you forget to turn down the heat on your dish after it comes to a boil. Luckily, you can re-thicken your soup or sauce by adding starch at the end of cooking with a beurre manie or by tempering in more starch.
You may also have noticed that dishes thickened with starch will thicken even more once they're off the heat and have cooled down. This happens because without the constant disruption from the all moving molecules, the starch will set into a stable structure with water trapped in between. Gentle re-heating will return the sauce to its original thickness.
All starches begin to thicken at around 60°C. But to achieve full thickening power, flour and cornstarch, which have a high percentage of a starch molecule called amylose, must come all the way to a boil and be held just below the boiling point for several minutes to cook off the raw starch flavour.
Flour thickens the sauce and is a bulk ingredient, also carbohydrate.)
If wholemeal, provides colour and texture
If Self-Raising, makes mixtures rise
Gluten in flour produces a stretchy dough
Provides fibre (especially if wholemeal)
Provides carbohydrate, Vitamin B, calcium and iron
Wheat flour is used in a white sauce
Keep products moist and extend shelf-life
Add colour to foods
Provide energy and Vitamins A and D
Types of a roux sauce
Blond – used for a Veloute sauce –this is a mixture of flour, fat and stock.
Brown – used for an Espagnole sauce- this is a mixture flour, fat and veal stock.
There are three types of roux:
White – used for Bechamel sauce, this is a mixture of flour, fat and milk
A gelatinised sauce making method that makes use of these processes is the Roux sauce. Roux is a thickening agent for liquids, and it's a fancy name for flour mixed with fat. Equal parts of butter and flour get cooked over a medium heat, before liquid gets added gradually, stirring after each addition.
A process that occurs when starch is mixed with a liquid and heated; the starch thickens the liquid.