Shake well is an instruction commonly included on food products with liquid ingredients that easily separate into distinct layers based on ingredient density. Consuming the product without shaking is usually not harmful but will result in dispensing only one part of the total ingredient mix, which may result in unusual flavors or food texture.
- Natural juices such as orange juice tend to contain pulp that separates from the liquid-only components, and must be shaken to distribute the pulp throughout the liquid.
- Oil and water products such as salad dressings tend to separate into two layers containing the water-soluble and oil-soluble components.
Raw milk is one of the few natural food products which would normally separate into layers, but most milk is now homogenized, so the fats have been broken up into smaller sizes that form an emulsion that will not separate, and there is no need to shake it.