An emulsion is a mixture of two immiscible liquids (like oil and water), where small droplets of one liquid are dispersed throughout the second liquid. Emulsions can be classified as follows:
- Oil in water emulsion – where oil droplets are dispersed in the water phase e.g. homogenized milk or a “creamy” style salad dressing.
- Water in oil emulsion – where water droplets are dispersed in an oil phase e.g. margarine.
Let’s Start with Milk
The purpose of homogenization in milk is to break down the fat molecules so that they remain suspended throughout the milk and resist separation. Without homogenization, fat molecules will rise to the top and form a layer of cream, with the watery liquid or skim milk at the bottom.
Homogenization of commercial milk is widespread and expected by consumers in the USA. So much so, that the federal classification of milk IS homogenized milk, and the law does not require homogenized milk to be labelled as such. Homogenization is a purely mechanical process and doesn’t involve any additives.
A dairy processing facility will typically separate the milk into skim milk and cream. They then go on to recombine (homogenize) these to make products of the desired fat content, like whole milk (3.5% fat), reduced-fat milk (1% or 2% fat), and skim milk (0% fat). Yogurt, cheeses, and ice creams of varying fat content are made the same way, by recombining the components.
Homogenized Food Products
Homogenization is widely used throughout the food industry. It is common in the manufacture of any milk-based products to prevent a cream line or sedimentation, e.g. in chocolate milk or iced coffee drinks. Homogenization is used to improve the viscosity, taste and texture of cream or juice-based drinks, to improve the mouthfeel of soy beverages, and to prevent the separation of the whey in yoghurt. Some cheeses are produced using homogenized milk, especially when manufacturers want to control the fat content, texture and color.
Many other food products benefit from homogenization:
- cream cheese
- ice cream, cream products and dessert toppings
- salad dressings
- flavor emulsions for beverages, yoghurts, candy and countless other products
Pion's BEE brand Homogenizers: High Pressure Homogenizers for the Food Industry
At, we understand food processing. Our equipment is designed for sanitary applications, and our unique, modular technology supports a wide variety of process configurations including a high pressure pasteurization option. Stringent FDA requirements are met with options such as automated control, in-line process design, data gathering, SCADA and validation documentation.