Here is the data table for the performance of this vat. It only has the option of full power on or off so these results should pretty consistent. I used one gallon of water in the water jacket and five gallons of water in the batch pan.
Please note that milk may have different thermal properties than water so it could heat faster or slower than what is depicted here.
This graph will expand if you click on it.
(Please note that the power was cut at 50 minutes)
Here is the data table which is probably more useful beyond just visualizing the relationship between the two temps.
I'm not sure why I can't get this to show up bigger... it will expand slightly if you click on it.Conclusions
#1- For a five gallons, the Batch Temperature should lag predictably by 11 degrees behind the Water Jacket Temperature.
#2- The residual/carry over temperature of the batch from the time the unit cuts off should be about 8 to 10 degrees if the Jacket is leading by the full 11 degrees. This would be most useful when setting the temperature for ripening the milk.
#3- This thing heats much too quickly to cook curd slowly so I would recommend bumping it up a degree or two at a time and letting the temperature equalize. Keeping the Jacket Temp closer to the Batch Temp will slow down the process.
#4- The most important residual temp/carry over number is the Water Jacket. It was only 3 degrees with an 11 degree differential between it and the Batch. The carryover would likely be higher if the Batch was closer to it's temp because the batch wouldn't absorb as much of the heat.
#5- After all of this, I think what Ive realized is that unless you can control the amount of heat the element is producing, you can never "set it and forget it." That being said, this setup should be an easy way to control your temperature in a very precise way without taking your vat in and out of the water. If anyone else ends up using this set up, I be very interested to hear your insights on how to most effectively put this thing to work.Done! WooHoo!