What is Tempering and how do you do it?

"Tempering refers to the blending of ingredients of different temperatures.  There are two common uses of the term, to temper eggs or to temper chocolate, although the way tempering works differs between the two.

In tempering eggs, you add a small amount of a hot liquid into relatively cooler eggs in order to warm them up without scrambling them.  This method is used in making custards, egg-based sauces, and other foods where eggs are used to thicken a hot liquid.  If you simply dumped the eggs into the hot liquid, the heat would transfer immediately to the eggs causing them to scramble.  To avoid this, the liquid is removed from the heat and a small amount is poured slowly into the beaten eggs while they are whisked."

See entire explanation @ Kitchen Savvy

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