85 Degrees

Last week, a 3 hour test of the vat resulted in a 16 degree rise in vat temperature, and I learned we had it hooked up wrong and needed more water flow.

This past week, I corrected the plumbing and installed a faster pump.  Yesterday, I learned that our tankless hot water heater is the choke point. It’s rated at 4.2 gallons per minute– enough for an entire home, but not enough to pasteurize a hundred gallons of milk.

In a moment of inspiration (or an attack of insanity) I installed a valve to allow water to bypass the tankless heater, thereby giving me the option to increase the flow, though at a lower temperature. I used the tankless to heat up the 320 gallon water reservoir, since it’s snowing and there’s no help from the sun this weekend. Then I used the already-heated water, in combination with the tankless heater, to heat the vat.

The result: it took 1 hour and 15 minutes to heat from 58 degrees to 85 degrees, an increase of 27 degrees. That’s hot enough to make cheese– I call that a successful test.

It’s not enough heat transfer to pasteurize, which requires heating to 145 degrees. For that, I’ll need additional water heating, either from the sun or from a second tankless heater, which will take a couple of weeks to arrive and hook up.  But at least we can now make aged cheeses!