6 replies to this topic

[DanOLeary]

I recently switched from a plastic picnic cooler mash tun to a converted stainless steel keg. I've brewed 3 times with the new mash tun and I keep coming up low on my desired temperature at mash-in. With the plastic cooler I was using a thermal mass of 2.2 and my strike temperatures for mash-in worked very well, usually hitting within a degree or two. I've been increasing the thermal mass as a guess, but after three brew days I'm still coming up low. What number do you use for thermal mass of your stainless steel mash tun?

[CaptRon]

Promash I assume??You can figure out your tun's thermal mass by doing the followingI found this information via a google search, so I'm not the smart guy that figured this out. 1. Go into ProMash and open 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!

[Sidney Porter]

if you are heating the strike water in the keg the thermal mass should be 0. You are not going to lose any additional temp to the keg once you reach you strike temp.No idea if you are dumping hot water into the keg. If you are doing this I would use a cooler.

[DanOLeary]

Hey Thanks! I guess I could have Googled it myself but I thought someone would already have a good number. I'll go through the steps and see what I come up with.I'm actually using a program called Beer Alchemy.https://www.kentplac...eerAlchemy.htmlIt's a Macintosh only application which I have been using for about 3 years and I love it. Thanks again for the instructions.

[MtnBrewer]

I found this information via a google search, so I'm not the smart guy that figured this out.

You're working too hard! Coulda just looked in the FAQ.

[CaptRon]

You're working too hard! Coulda just looked in the FAQ.

[3rd party JKor]

Hopefully you are insulating that keg. The type of insulation will have an effect on the thermal mass, as well.