Water-Jacketed Churn: Hot or Cold Water Under a Metal Plate Tempers the Cream

"For using the churn herein described, the dash being placed in the churn, and the spindle screwed in, put in the milk or cream to be churned; if not in the right degree of heat apply the hot or cold water in the chamber or space, under the milk or cream until it becomes the right degree of heat required, being about sixty degrees."

Print two end pieces flat, grooved face up (/uploads/blueprints/water-jacketed-churn-end.stl), two dash crosses (/uploads/blueprints/water-jacketed-churn-cross.stl), the crank arm (/uploads/blueprints/water-jacketed-churn-crank-arm.stl) and the drain plug (/uploads/blueprints/water-jacketed-churn-drain-plug.stl). Print in PLA at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Cut a 0.5 mm stainless sheet 160 mm wide and long enough for a 70 mm radius half circle with 60 mm straight sides, about 340 mm. Deburr it and bend it round a 140 mm form into a U. Stainless will not oxidise in the cream, as the patent required.

Seat the U in the curved grooves of both end pieces, and plywood sides and a bottom in their grooves, all bedded in silicone, leaving a closed chamber 25 mm deep under the U and 12 mm beside it. Let it cure, then fill the chamber with water and check for leaks. Glue the crosses on a 12 mm hardwood dowel spindle, glue eight 6 mm dowel slats into their holes, pass the spindle through the end pieces and glue the crank arm on. Press the plug into the drain.

Pour in 500 ml of heavy cream and measure its temperature. Pour water into the chamber at the temperature the notebook gives, and wait until the cream reads about 15.6 °C. Turn the crank thirty to fifty times a minute, as they did, and time until the butter comes. To gather it, turn the dash half around and back a few times. Pour off the buttermilk, add cold water, churn a little and pour off again until it runs clear; work in a pinch of salt and weigh the butter.

**William A. Crowell and Allen Crowell** of Salisbury, Litchfield County, Connecticut, received US 1,648, dated 20 June 1840. Their chamber was two inches wide; a tube at the top let the water in and one at the bottom drew it off; a thermometer could be fitted through the end piece with its card outside. The division plate was "to be made of tin or other metals which will not become oxidized by the action of the acid contained in the milk or cream." They claimed the combination of tin and wood, or other metal and wood, or all metal, in forming a chamber in the lower part of the churn with a metal division plate. **Honest limits.** Stainless sheet, plywood and printed end pieces stand in for their tin and boards. The notebook ignores heat lost to the air and the box. FDM prints hold food in their layer lines, so wash well and replace when worn. Your temperatures, times and weights are the result.