Churn, a vessel in which cream is agitated to separate the butter from the other portions. It has various forms, the simplest and most generally preferred being the common dash churn, which is either a cylindrical or barrel-shaped vessel, standing upon one end and having a cover fitted to the other, with a hole in its centre for the passage of the handle of the dasher. This is the instrument for producing the agitation of the cream, and consists of a wooden rod a little more than an inch in diameter and from three to four feet long, having two boards attached crosswise at the lower end, of a length somewhat less than the diameter of the churn. The form and size of these cross pieces are important, as upon them depends the proper agitation of the cream. The motion which has been found to give the best results in churning is that which produces a thud or shock, such as would be given if a keg or small slender barrel, partly filled with a liquid and suspended in a horizontal position by both ends, were swung in one direction, endways, and then suddenly stopped; and, indeed, this form of churn has been used in Holland, England, and the United States, and for making small quantities of butter is probably the best. It is called a swing churn.

An ingenious contrivance for imparting a similar motion to the contents of the churn has been invented in England. It consists in revolving a barrel-shaped vessel upon a diagonal axis, by means of which each end is alternately raised and lowered, thereby throwing the cream from one end to the other. Wheel churns of an almost endless variety have been invented, and some of the simpler forms answer the purpose intended very well; but they are all inferior to the dash and swing churns. Some combine aeration with agitation, by forcing streams of air through the cream; but such contrivances are now regarded by all good butter makers as worse than useless, because, although they may quickly effect the rupture of the butter globules, they incorporate the sacs and other portions with the butter, rendering it liable to become rancid by fermentation. The design in many of the inventions has been to hasten the operation of churning; but it has been found that when cream is in the best condition for making butter, the time occupied should be from 40 minutes to one hour. (See Butter.)