Milk churns through a physical process of agitation that breaks down fat globules and allows them to bind together, ultimately forming butter.
Here's a more detailed breakdown:
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The Cream's Composition: Milk contains fat globules suspended in a water-based solution. These fat globules are surrounded by a thin membrane. When milk separates, the lighter cream rises to the top, containing a higher concentration of these fat globules.
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Agitation Breaks the Membranes: Churning involves vigorously agitating the cream. This agitation provides the mechanical energy needed to rupture the delicate membranes surrounding the fat globules.
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Fat Globules Clump Together: Once the membranes are broken, the fat molecules are exposed and start to stick together. The more you churn, the more these fat molecules collide and coalesce.
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Butter Formation: As the churning continues, the clumps of fat grow larger and larger, eventually forming a solid mass: butter. The remaining liquid, known as buttermilk, is separated from the butter.
In essence, churning physically disrupts the structure of the cream, allowing fat to bind together and separate from the liquid.
