Egg Yolk

Egg yolk adds a silky finish to a sauce and is used in white and blond sauces. The egg yolks are usually mixed with cream, and then tempered by adding some of the hot liquid (stock) before being incorporated into the sauce to be thickened. Because egg yolks will begin to coagulate over 85°C (185°F), they are incorporated off the heat and never put back on the heat. Sauces thickened with egg yolk need to be served immediately and are difficult to reheat for later use. However, they can be prudently heated in a hot, but not boiling, bain marie.