Measuring Your Thermal Mass with ProMash, contributed by the_stain Options

[cj in j]

Calculating Your Thermal Mass with ProMash
contributed by the_stain

Q: What is the Thermal Mass of my mash tun, and how can I calculate it?
A: Thermal mass is the amount of heat your mash tun will absorb when you add the water. This can affect your calculations a bit when attempting to calculate your strike temperatures.

The default or "average" thermal mass of 0.30 will get you pretty close most of the time, but you can measure it yourself with the following procedure:

1. Go into ProMash and go into the Strike Temp calculator.
2. For Mash Tun Thermal Mass, Enter 0.
3. For Total Grain enter 0.00001 pounds. (It won't let you go any smaller - entering 0 will give you a division error.) This should make your water:grain ratio 120000:1.
4. For Total Water, enter 16.00 quarts.
5. For Desired Strike Temp, enter 170. (You can use any temperature but this will more accurately reflect actual mash temperatures.)
6. For Grain Temp, enter the current room temperature.
7. Heat 16 quarts (4 gallons) of water to 170 degrees and pour it quickly into the mash tun. Close the lid and seal it up, and let it sit for about 5 minutes.
8. Measure the temperature of the water in the mash tun.
9. Enter the temperature of the water in the mash tun in the "Desired Strike Temp" field in ProMash.
10. Now look at the "Initial Strike Water Temp Should Be" window. You will note that, with Thermal Mass set to 0, this number will be the same as the "Desired Strike Temp" field.
11. Now, in small (say 0.1 or smaller) increments, increase the Thermal Mass field until the "Initial Strike Water" field reads 170 (or whatever temperature you started with, if you didn't use 170 for some reason.).
12. Ta-da! Whatever the Thermal Mass field says is your mash tun's thermal mass!