Advice needed on the Igloo 60 quart...

I have recently converted an Igloo 60 quart to a mash tun and I broke it in with a simple steep of 2 lbs of vienna and 1 lb of rolled oats. I used about 1 gallon of water with the 3 lbs of grain. This of course leaves a TON of headspace in the tun, but it was just a partial mash kind of thing.

I had a TERRIBLE time with the temperature. I preheated the tun with boiling water up to three or four gallons. Emptied that and then put in my strike water at the prescribed temperature for the grain and variables. (I was trying to steep at 154 for 45 minutes.)

First, my temperature was nowhere near 154 after doughing in. I wasn't terribly worried about this, because due to the configuration of the cooler, my thermometer was actually slightly above the "grain line" with 1 gallon of liquor and 3 lbs of grain.

I put an independent thermometer in and sure enough, I was about 25 degrees low. So I added 1/2 gallon of 200 degree water to increase the temperature.

Long story short, I ended up having to add way too much strike water to hit my temperature.

Does anybody have any good suggestions for warming the tun? Clearly I need to experiment with my strike water to see just how hot it "really" needs to be in order to hit my target temperature for that cooler but if anybody has any experience with partials and steeps for that mash tun, please let me know.

Thanks ahead of time.

On a larger grain bill it will be easier for you to hit your temps without all the deadspace. Do you have any software like beersmith? I use a free online calculator called beercalculus at hopville.com. I normally just use my strike water to pre-heat (doing full size batches with around 12lbs of grain). My strike temp is usually about 10 degrees higher than my mash temp with those volumes so I add my strike water in about 20 degrees higher than I want my mash temp to be. I close the cooler and let the temp drop to about1-2 degrees higher than my desired strike temp and then I dough in and stir for about 5 minutes until I am down to my mash temp. Close the lid and let it sit for 60 minutes.

I used a couple of online calculators and they recommended a strike temp of 167 for my grain bill and the the ambient temperatures. (Again, I was going for 154 in the steep.) Like I said, I tried to 'pre-heat' the tun with nearly boiling water but it still seemed to drop temperature like crazy.

Maybe that tun is just too large for these kind of small steeps. I do think it will be fine with an all-grain batch because of the volume. I can always just use a smaller cooler for the low volume stuff.

Edit, not that it matters, but I used 1 lb of 120 Crystal rather than rolled oats. I just noticed I typed in the wrong grain there and wanted to clarify for my own sake.

1 or 2 gallons of hot water in a big space with a larger surface area.. My opinion only, but there is not enough thermal mass in that small amount of mash to maintain decent temperature control.

bosco

I'm going with "bad measurements" for this one. Room temp grains will drop the water temp about 10 degrees, not 35. Even an uninsulated container probably won't lose 25 extra degrees over a 45 minute mash, let alone the couple of minutes of stir in time.

In terms of maintaining temps, the rate of energy loss from a cooler is proportional to the temp difference between inside and outside. The total energy loss is going to be the same for a small volume vs large volume. However, gas holds very little energy compared to liquid, so that energy loss is coming primarily from the liquid. When you take equal amounts of energy away from different volume items, the one with the smaller volume will see a bigger temperature drop. ie the small volume cools faster

Trying to mash 3lbs of grain in a 60 qt cooler is just not a real good idea IMHO due to all the vacant head space. For such a small amount, I would try using a small stock pot, and put it in a warm oven to maintain temperature.

I will agree with the rest, the amount of grain used is way too low to effectively guage the temp control for the cooler. I have a 70 quart Coleman and pour my strike water directly in about 10-12 degrees higher than my mash temp and get within a degree. This is of course using a grain bill of 17-20 lbs.

Ya, that's where I was at with it. I think I'll forego the big tun and just use my small cooler for these partials. I should have done it that way in the first place but I was excited to use the new tun.

I'm doing an all-grain batch in a week or two. I'm sure temp. management will be much easier.

I also might try doing the steep in an oven safe pot and trying to maintain the temp that way. For a 45-60 minute steep that should work really well. Thanks for the input everyone. I do appreciate it.

My MLT is giving me no end of grief. This Igloo 60 quart seems to leak heat like a sieve. The lid is uninsulated so I've been covering the entire cooler with a thick blanket but I'm still dropping from my strike temp of 167 to around 140 over my mash period. (In fact the cooler drops to that temperature within about 20 to 25 minutes after closing the lid.)

I've verified the thermometer is reading correctly and I'm doing 15-17 lb grain bills. There is still a fair amount of headspace in the cooler, but I can't understand why it's dropping so rapidly. Ironically, once it hits around 140, it stays there pretty faithfully. Maybe it's a thermometer placement issue...

Anyway, in order to resolve I'm just going to manually recirculate the wort through my HLT coil with a march pump in order to maintain temperature. It's just irritating that the darn thing doesn't seem to hold temp and I don't see too many other people having the same problem.

Are you thoroughly preheating the cooler? Try adding strike water 15 degrees high, say 180 degrees, and let it sit for 15 minutes, then adjust downward to strike temperature with a little cool water or a few ice cubes, the cooler must be thoroughly preheated! You want to "stabilize" at mash temp...not at like 140 as you are doing.

Granted I think that cooler is a little large for 15-17 lb grain bills, but you should be able to do better than you are. Also do not check mash temp immediately after stirring in the grain, it takes at least several minutes for the heat to distribute, stir well let sit 5 min, stir again and check.

167 strike temp sounds too cold if you are adding to a ambient temp cooler IMHO.

I think it is your technique, rather than the cooler.

honestly, unless you are putting in refrigerated grains, I would get rid of that cooler as a mash tun and get a new one. I have a 48 quart Igloo Marine cooler that I use. It's not exceptionally thick walled and the lid can be a little wonky at high temps. But I mashed last Sunday at 152 for 60 minutes in it with an ambient temperature of 36 degrees. I threw a moving blanket over the top of it, because it will lose heat around the lid handle. None the less, I lost 1 degree over the course of those 60 minutes.

Something seems really wrong with your system, either the grain you are adding is a lot cooler than you thought, or the Mash tun you have isn't insulated at all. What kind of thermometer are you using? Maybe it's not accurate at temps over 150, so you actually aren't getting to the strike temp you need? I've tested a lot of thermometers since I started brewing, very few of them are anywhere close to correct. Seems crazy to me, but for all the issues you are having, I would just go out and get a new cooler and see how that works.