Milk skin

Milk skin ( regionally known as smut, Flähme ( altböhmisch ) Flott, Pelle or fleet ) is a film which occurs when heating milk. The skin formation in the milk after the cooking process is a complex process. It depends on various factors such as the heating and cooling conditions. Fat content and homogenization are other important factors. By the evaporation of water is formed on the surface of heat-treated milk, a skin milk, which consists of approximately 70% fat and about 20-25 % protein. Of the proteins involved is probably the majority of denatured lactoglobulin, but also the somewhat less heat-sensitive albumin is likely to be present in the skin to a range of smaller proportion. According to recent findings, however, casein probably plays a minor role. But now there are no extensive studies.

If milk is heated to about 75 degrees Celsius, the bundle of molecules disentangle ( denaturing ) and glue ( aggregation) then another. Thus, a thin net-like structure, the milk skin forms. This is due to the thermal coagulation of albumin and globulin, which already uses if heated above 70 ° C. Since the skin is lighter than water, they always drives at the surface. A full-fat, non-homogenized raw milk forms for example when cooking a vollmundigere and thicker skin than a homogenized milk drink. When ascending water vapor accumulates under this milk skin and this raises it comes to the typical effect of boil the milk.

Milk skin is perceived by some people as distasteful or even disgusting. Avoid it can be. By careful not to strong heating and simultaneous whipping or foaming of the milk, for example, with a whisk, which prevents the formation layer underlying In addition, the stirring of the milk to prevent this process, as this air enters the milk, which is enclosed by the clotting proteins. Thus is formed instead of the milk skin milk foam.

In the molecular gastronomy milk skin is also used as an ingredient. Ferran Adrià prepares it to, for example, pancake or ravioli.