To create an oil and water emulsion, it is necessary to put in a great deal of energy and to add an emulsifier to the mixture. Creating an unstable emulsion only requires stirring the mixture fast. To make a stable version, add egg yolks.
- Combine oil and water
Put equal parts oil and water in a bowl. The two ingredients stay separated because water molecules are polar, but oil molecules are not polar. The water binds with other water molecules, while the oil binds with oil molecules.
- Mix the oil and water together
Stir the two ingredients vigorously with a cooking whisk until the oil and water begin to mix together. This mixture is unstable, so do not let the ingredients sit in the bowl undisturbed for more than a few seconds.
- Separate the egg
In a separate bowl, crack open one egg, and separate the yolk from the egg white. If the oil and water mixture separates while you do this, stir the mixture again before adding the yolk.
- Add the yolk
Drop the yolk into the mixture, and quickly stir the ingredients. Whisk the water, oil and egg together until they combine evenly throughout the bowl. Let the emulsion sit undisturbed for a few minutes to check on its quality. If the ingredients continue to separate, add another egg yolk, and then stir again.