🔄 Homogenization

Homogenization means breaking up fat globules so that the cream does not separate. In fresh milk, fat floats as tiny globules about 3.5 micrometres in size. They are lighter than water and over time rise to the top, forming a layer of cream. A homogenizer pushes hot milk through a narrow gap at a pressure of 100–250 bar. The globules break down to less than 1 micrometre and no longer float up.

After homogenization, milk looks whiter, tastes fuller, and its fat oxidises less. Yogurts and other fermented milk products come out smoother. There are downsides too. Such milk is more sensitive to light and can pick up a “sunlight” off-taste. It is awkward for hard cheeses: the curd is soft and releases whey less well.

Homogenization was invented by the Frenchman Auguste Gaulin at the end of the 19th century. He showed his machine at the World's Fair in Paris in 1900. The first country where almost all milk was homogenized was the USA. Milk is usually homogenized right before pasteurization or together with it. The heat switches off enzymes that would otherwise quickly make the broken-up fat go rancid.