Mash tun performance

For all who mash in converted coolers, how many degrees does your guys mash drop during an hour rest? In a test run with just water, mine dropped about 2.5 degrees over an hour, which seems kinda sucky.

That is really good! When you have grain in there, you will see a little less, the grist will hold heat better than water will.

It all depends on your cooler, too. What kind of cooler do you have? With some coolers the lid is not insulated....it's just a hollow lid. If this is what you have, go to Home Depot or any other hoe store and buy a can of "Great Stuff". It is an expanding insulating foam. Drill a few holes in the top of the lid, spray a bunch in there and TADA!!!.....insulated lid.

talleymonster said:

It all depends on your cooler, too. What kind of cooler do you have? With some coolers the lid is not insulated....it's just a hollow lid. If this is what you have, go to Home Depot or any other hoe store and buy a can of "Great Stuff". It is an expanding insulating foam. Drill a few holes in the top of the lid, spray a bunch in there and TADA!!!.....insulated lid.

Click to expand...

I did that earlier this week actually. Great minds.....

Just wondered what the average performance of the converted cooler is. Mine is a 5 gal. cylindrical. And man, does "Great Stuff" make a mess. That stuff does NOT come off your hands. I had to raid my GF's nail polish remover to get rid of it. She's gonna be pissed.

and hoe store is funny.

I'm a terrible typist. I hunt and peck all day. I never learned the "home row" as a kid.

I used to loose 6-7 degrees with my blue square igloo but now that I used a can of "Great Stuff" in the lid, I only loose 1 degree.

A loss of 2.5 degrees over an hour is damn good using just water! As others have indicated, the grist will hold heat much better and you'll hold temps pretty closely. I expect a degree of loss over the hour.

Insulating the lid with GS works extremely well, but I've started using a piece of two-inch thick foam insulation cut to size and laid on top of the grainbill- didn't lose nary a degree.

0 (with grain)

When you did your test run, did you pre-heat the cooler?

Yes I did, dumped in 185 degree water and let it chill for half on hour, then opened it and let it come to mash temp. I only used 3.75 gal, so I guess it works better than I thought.

Do you guys ever compensate for the temp drop? Say if it drops 2 degrees, mash in a degree higher than your goal so the average temp is at your rest temp?

smizak said:

Yes I did, dumped in 185 degree water and let it chill for half on hour, then opened it and let it come to mash temp. I only used 3.75 gal, so I guess it works better than I thought.

Do you guys ever compensate for the temp drop? Say if it drops 2 degrees, mash in a degree higher than your goal so the average temp is at your rest temp?

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No I don't but once I hit my target temp it doesn't drop. If it did I would try wrappng it in towels or keeping it in a warmer spot or something. 2 degrees isn't a heck of a lot though really. With grain you probably won't see any drop worth noting.