The words used in ingredients may be common, but their meanings can be tricky. That's why it's important to understand the language of cooking. Browse through my Glossary, or read a big cookbook so you understand cooking and baking terms. It's hard to make a pie crust, for example, if you don't know what "cut in" means, and it's impossible to make mayonnaise if you don't know what "emulsify" means.
Béarnaise sauce, hollandaise, mayonnaise, salad dressing, and other sauces are examples of emulsified foods.
Emulsify means to combine two ingredients together which do not ordinarily mix easily. The ingredients are usually oil or a fat like olive oil or egg yolks, and another liquid like water or broth. The force of beating is used to combine these ingredients. Add-ins such as mustard or an acidic ingredient can also help the mixture cohere.
The liquids are combined very slowly, usually drop by drop, while beating vigorously, which suspends drops of liquid throughout each other. A food processor or blender is an excellent tool for this task. You can also use
Acidic liquids like lemon juice help the process by changing the pH of the mixture. That's why you'll often find lemon juice or vinegar in recipes where you emulsify liquids.
These mixtures can sometimes split, or separate, if you combine them too quickly.
If that happens, add a teaspoon of water and whisk the mixture, or blend it in a blender until it becomes smooth again. Sauces made with egg can be re-emulsified if you slowly whisk or blend them into another egg. (Please use pasteurized eggs, not raw eggs, when you make these recipes, for food safety reasons.)
Here's how it's used in a recipe: To make a bearnaise sauce, egg yolks and water must be emulsified so the mixture is creamy, thick and smooth.
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