Sauce-a flavored, thickened liquid usually made by adding a thinking agent, seasonings, and flavorings.
Thickening agent-an ingredient such as cornstarch, that adds body to the sauce.
Béchamel- two sauces that aren't made with a thickening agent, a simple French white sauce made with milk and a thickener, and hollandaise sauce.
Hollandaise sauce- sauce made from lemon juice, butter, and eggs.
What makes a good sauce?
A good sauce is always a nice complement to the food, they are not supposed to over power or detract from the food that they are used on or with.
today many restraunts use condensed or powder based sauces then when mixed with water create a commercial sauce that tastes the same every time.