The improved modern method, now in practice by the best butter makers
generally, is to stop the churn as soon as the butter is collected in
particles the size of wheat kernels. Just before this, when the first
signs of the separation of the butter is seen, the sides of the churn
are washed down with cold water--usually below 60 degrees, or about 55
degrees--to not only prevent waste, but to harden the butter and make
it easier to handle. When the granules are the size of wheat kernels,
the butter is drawn off or the butter taken out of the buttermilk, as
the case may be. If the butter is left in the churn, water is poured
in to float the butter, which is then gently agitated a moment and
the water drawn off. This operation is repeated until the water runs
clear. Sometimes one of the washings is in brine, which coagulates the
caseine into a soluble form and prepares it to be washed out afterward.
In this way, it is believed that purer, longer-keeping butter can be
made. In some cases, however, butter makers have customers who want a
buttermilk flavor in their butter. They, therefore, do not wash the
butter, or wash it very little. Such butter must be consumed at once,
as it will not keep.