Learn the most important elements of any sauce the ability to smother and cling to whatever it gets drizzled, dolloped, or poured on. That means making the sauce thick and stable, which is accomplished with three techniques: a roux an emulsifier, and a reduction (liquid that's slowly cooked down until thick). Three out of the five mother sauces start with a roux. Roux is a fancy name for flour mixed with hot butter. Equal parts butter and flour get cooked over medium heat, then a liquid gets added. This mixture then boils, thickens (reduces), and becomes the base of your sauce. Just note, if you’re making a white sauce — like Béchamel or Velouté — do not brown the butter, as it will darken the finished product. The tomato sauce could be thickened by just reducing it or adding beurre manie (French "kneaded butter") is a   consisting of equal parts of soft butter and flour, used to thicken soups and sauces at the end. The last mother sauce is a product of emulsification All techniques are shown and explained in my videos.