Friday, October 14, 2011

Culinary IQ: Friday, October 14, 2011; Egg Coagulation

Right in the Middle of Things

Eggs are frequently used in baked goods to assist in the structure of the item by binding it together. How does this happen? As the mixture with egg in it is heated the proteins in the egg seize and become firm. The higher the heat the firmer the structure. Coagulation is the term used for the seizing of the proteins. Egg whites coagulate somewhere between 140°-150°F and egg yolks coagulate somewhere between 150°-160°F with a whole egg coagulating somewhere in the middle.

The basic egg custard consists of eggs, milk or cream, sugar, and flavoring. The mixture is thickened or gelled through the heat coagulation of egg proteins. Example of egg custards include crème caramel, crème brûlée, and crème anglaise--vanilla custard sauce. Many other products have a custard base. For example, pumpkin pie filling, cream pie filling, bread pudding, rice pudding, pastry cream, quiches, even cheesecakes are variations on the basic egg custard.
A properly cooked custard-based product is a moist, tender gel or a smooth, creamy sauce. The thickening and gelling occurs over time as the temperature of the mixture increases and the eggs coagulate.
Helpful tip: Water baths are good for baking egg custard, bread pudding and cheesecake. Water baths rarely exceed simmering (180°-190°F), even when the oven is set to 325°F or more. This slows the process and evens out baking so that the outside of the custard does not become tough, rubbery, and curdled before the inside bakes.
To use a water bath, place filled containers to be baked in a pan. Place the pan in the oven and fill with hot water at least halfway up the sides of the containers. Do not fill so high that water sloshes into your product.*
One of the most versatile egg custards is Pastry Cream. It can be used in fruit tarts, eclairs and cream puffs, as well as flavored for cream pies. Please follow this link to an easy delicious recipe for pastry cream.

Next week I will cover chocolate, probably the most loved food in the world.
*Adapted from How Baking Works: Exploring the Fundamentals of Baking Science

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