Sorry to deep res this thread -- found it on a search

I just did this on paper for my own use...

You can follow the same steps. You're interested in the following measurements:

I assume Beer Smith calculates thermal mass in calories -- I don't have the program installed at work to check.

1. Weight of water (in grams) (Mw)

2. Initial Temperature of Mash Tun (Tt) (temp. units don't matter - they'll cancel)

3. Initial Temperature of Water (Tw)

4. Final Temperature of Water (Tf)

The equation for thermal energy (see Beer Smith documentation)

MwTw + MtCtTt = (Mw + MtCt)Tf

All values are known except MtCt, which is the thermal mass of the tun.

Solving for MtCt:

MtCt = Mw (Tf - Tw) / (Tt - Tf)

All values on the right side of the equation are known.

If Beer Smith requires the tun's weight, you can weigh it and find out the specific heat -- or just use a dummy value. This will work, but it's not actually *correct*.

This has been my problem with this value all along (and is part of why I've gone and figured it out -- also, I'm learning Android programming )... a cooler is an inner wall and an outer wall with insulation between. The thermal mass really consists of only the inner wall and some of the insulation -- insulation likely has low thermal mass, but the *rate* of heat transfer is decreased. This emulates a closed system for a period of time.