Churning is the mechanical agitation of cream used in butter making. The churning action ruptures milk fat globule membranes, letting fat globules collide and coalesce into butter grains that separate from the buttermilk. Continued working expels more buttermilk and forms a continuous fat phase that becomes butter. Control of cream temperature, fat content, and churning time determines butter texture, moisture content, and keeping quality. Too warm and the butter turns greasy; too cold and churning drags on, so dairies fine-tune conditions for each batch.