Butter has been made for thousands of years, and although the machines and equipment used to carry out the process have become more advanced, the functions they serve have mostly remained the same. Whether it is a farmer making butter on a small scale level or a milk plant processing it for distribution, the equipment is similar.
No matter where the butter ends up being made, it must be first milked from the cow. A milker is attached to the teats, where pulsation from a vacuum creates a squeezing sensation that drains the udder of milk. Milking generally occurs twice a day, although some farms milk three times a day. In most cases, the milk travels to a bulk tank, where the farmer collects it to make butter. However, the farmer may choose to separate that cow's milk out specifically to use by having it flow into a stainless steel bucket attached to the milker.
The first step in making butter is to segregate the skim milk from the cream using a machine called the separator. The separator uses centrifugal force to cause the cream to rise to the top. The skim milk is drained from a spout at the bottom. The cream is then chilled. The thickness of the cream can be manipulated by an adjustment on the separator. As in every process of making butter, the equipment must be sterilized before and after use.
Wooden churns were used for hundreds of years while housewives made butter at home. They had to mix the cream by hand until the fat globules began to solidify. Today, the process is the same, but butter no longer has to be churned manually. In small scale operations, a stainless steel vat is filled three quarters full with cream that has been warmed to about 65 degrees F. The arm moves mechanically, but slowly, to avoid "whipping" the butter instead of churning it.
Before it can be weighed, salted and distributed, the butter must be washed of buttermilk. At the milk plant, this step is part of a process carried out by a large butter-making machine that runs cold water over the coagulated butter. On the farm, however, this step is typically done by hand. The butter is placed in a shallow pan under a tap while someone kneads the butter, working until the wash water runs clear. The wash water must be squeezed out of it before the butter is ready to be packaged.