Hydrothermal Reservoir Dasher Churn: Warm Water in the Dasher to Churn, Cold to Firm the Butter

"These particles are not spontaneously accumulated in concrete mass, but by the aid of cold water substituted in lieu of the warm water, which is withdrawn from the dasher by detaching the dasher from the churn vessel, the concave gatherers F, F, F, F, and h, h, h, h augmenting the concretion and forming the mass of butter without requiring much, if any, additional agency."

Print the hollow reservoir dasher with its four curved chambers, wings and filling hole (/uploads/blueprints/hydrothermal-reservoir-dasher-churn-reservoir-dasher.stl) standing up with 4 walls so it holds water, three or four hollow gatherers (/uploads/blueprints/hydrothermal-reservoir-dasher-churn-gatherer.stl), the 36-tooth crown wheel (/uploads/blueprints/hydrothermal-reservoir-dasher-churn-crown-wheel.stl), the 12-tooth pinion (/uploads/blueprints/hydrothermal-reservoir-dasher-churn-pinion.stl) and the standard (/uploads/blueprints/hydrothermal-reservoir-dasher-churn-standard.stl). Fill the dasher and gatherers with water and check for leaks before use. Print in PETG at 0.2 mm layers, 30 % infill, 4 walls; wash before first use.

Use a straight-sided round food-grade container about 190 mm across inside and 200 mm deep. Hook the gatherers over its rim, spaced round the side, their double-concave faces inward.

Slide the reservoir dasher onto a 10 mm stainless rod and tighten its set screw, its foot standing in a shallow hole in a scrap of the lid laid in the bottom. Fix half the lid over the vessel with a hole for the rod, the pinion on the rod's top, and the standard with the crown wheel meshing it; screw a dowel handle into the wheel's boss. Fit a cork to the filling hole.

Check the cream's temperature. If it is below about 15 °C, fill the dasher with lukewarm water, cork it and stir slowly until the cream reaches about 15 °C; if it is above, use cold water. Pour in 1.5 litres and turn the winch at a moderately rapid rate; time until the butter comes. Lift out the dasher, empty it, refill it with cold water or ice and water, and turn slowly to gather the butter. 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.

**Robert H. Harrison** of Washington, District of Columbia, assignor to R. H. Harrison and Jno. S. Gallaher, Jr., received US 10,690, dated 28 March 1854. He wrote that turning for "3 to 5 minutes" is all that is required for the separation, that fresh milk can be used, and that the wings act "as coolers or fans" drawing cool air in through a vent round the spindle; these are his claims, not tested here. He claimed the vessel with double concave gatherers or water reservoirs, the reservoir dasher with curved chambers and radial wings combined with them, and the double application of warm and cold water or ice with both; he did not claim the use of hot or cold water alone in butter making, "as the same have been employed separately, or distinctly heretofore." **Honest limits.** A container, printed parts and a crown wheel with a spur pinion stand in for his tin and bevel gearing. PETG softens at about 55–60 °C, so we use lukewarm water rather than hot. The notebook's temperatures are upper bounds with an estimated specific heat. FDM prints hold food in their layer lines, so wash well and replace when worn. Your times and weights are the result.