[Carson B]

(1: Preheat) I recently purchased an Infussion Mash Tun and have brewed one batch with it. I lost far more heat than expected in the mash (about 5 degrees), despite also using the MTSs (which I now think was a huge waste of money), which makes me think I preheated it incorrectly. I filled it up about halfway with 150 degree water and let it sit for about 10 minutes. My target mash-in was 155, which I hit, and it was 150 after 60 minutes.

I'm wondering how anyone else who owns this mash tun preheats it.

(2: Temperature Readings) Where do you measure your temperature from? I've always used a Thermapen in the top of the mash. I checked the Thermapen against the temp probe (MTSs), and found the temp probe to be spot on surprisingly. However, when I mashed in and over the course of the mash, the probe in the middle of the mash read about 5 degrees hotter than the Thermapen at the top.

Is this just a matter of hot and cold pockets, and which measurement should I be relying on? Going with the Thermapen makes me feel a bit more comfortable since I know how accurate it is, but then this makes the MTSs system irrelevant. Like I said before, the MTSs just might be shaping up to be a waste of money...

Thanks!

[ynotbrusum]

I have the 20 gallon tun.  I preheat with the strike water volume at 170F by filling the tun, drain, reheat as needed and underlet my mash.  However, I typically recirculate my mash, so temperature is not a huge issue if it is low, because it stabilizes at my set point within a few minutes.  Also the probe is in a thermowell, so it isn’t instantly stabilized - I give it ten to fifteen minutes and double check with a Thermapen.  Stirring well is important, especially when I don’t recirc, so I make sure not to open the lid during the mash, so as to avoid heat loss.  There can be cold spots, but underletting and good stirs usually even it out well enough and no unnecessary opening of the lid (just like cooking - leave the lid on or you lose heat!).

After a few uses you will get it down.  Cheers.

[BrewBama]

... (just like cooking - leave the lid on or you lose heat!).

...

+1

if you’re lookin, you ain’t cookin.


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[Visor]

   I doubt that a 10 minute preheat made much difference. I use a 10 gallon cooler mash tun, and although that is quite different from your system there are some similarities, what you're needing to heat isn't so much the mass of the metal or plastic which happens rather quickly, but rather the insulation and that takes time. I batch sparge & the sparge water volume is usually about 80% of the mash, I bring the sparge water to a boil, transfer to the MT and leave it for an hour or more while I do my morning routine, then transfer back to the sparge kettle just before dough in. Temperature drop over a 60 minute mash runs from ~ 2 to 4 degrees with smaller batches to 1* or none at all with maximum batches. Last Saturdays max batch only had ~ 3/4" freeboard and no measurable temp drop in 90 minutes. The reduced temp drop with larger batches results from a larger volume of preheat water heating the tun more, and the larger mass of mash retaining heat better than a smaller mash mass - just try saying that 3 times.
  I know that others have said that preheating is more trouble than it's worth, and it's easier to adjust your strike temp to account for temp drop. I prefer to keep my mash as close to my target temp as I can without having to decoct or rob from my sparge water by doing additional infusions. My methods my seem silly to some, but they work pretty well for me and at this point my recipes are all based on this process.
   

[ynotbrusum]

Definitely go toward setting a routine or a few routines that work for you.  Having boiling sparge water on hand can be a real lifesaver to adjust mash temp upward and frozen sparge water to reduce mash temp before enzyme mash out occurs.  I even used to use frozen water bottles to stir in the mash when I would overshoot on occasion (way back in the day).  Now with the ability to recirc, I undershoot more than overshoot, knowing that I can readily adjust upward.

Best of luck in your mashing! 

[Carson B]

Thank you for all the replies. Forgot to put notifications on so I did not see them till now!

   I doubt that a 10 minute preheat made much difference. I use a 10 gallon cooler mash tun, and although that is quite different from your system there are some similarities, what you're needing to heat isn't so much the mass of the metal or plastic which happens rather quickly, but rather the insulation and that takes time. I batch sparge & the sparge water volume is usually about 80% of the mash, I bring the sparge water to a boil, transfer to the MT and leave it for an hour or more while I do my morning routine, then transfer back to the sparge kettle just before dough in. Temperature drop over a 60 minute mash runs from ~ 2 to 4 degrees with smaller batches to 1* or none at all with maximum batches.

I can assure you the 10 minute preheat made no difference at all haha, yet this is exactly what SS Brewtech says to do to preheat it. I came from a 5-gallon Igloo to this. For the Igloo, I'd throw in 150 degree water for 15 minutes or so, then empty, then throw in the strike water and grain. Never lost more than two degrees doing it that way, so we're similar in that regard. It's been very frustrating going from a cheap system that works to an expensive that seems not to.

[Carson B]

I have the 20 gallon tun.  I preheat with the strike water volume at 170F by filling the tun, drain, reheat as needed and underlet my mash.  However, I typically recirculate my mash, so temperature is not a huge issue if it is low, because it stabilizes at my set point within a few minutes.  Also the probe is in a thermowell, so it isn’t instantly stabilized - I give it ten to fifteen minutes and double check with a Thermapen.  Stirring well is important, especially when I don’t recirc, so I make sure not to open the lid during the mash, so as to avoid heat loss.  There can be cold spots, but underletting and good stirs usually even it out well enough and no unnecessary opening of the lid (just like cooking - leave the lid on or you lose heat!).

After a few uses you will get it down.  Cheers.

So I ran an experiment last night similar to the routine you've described. I heated up five gallons (half of mash tun volume) to 175 degrees and put in cold tun. I let it sit for an hour. After that hour, the water was 164. I drained, heated the water back to 175, and filled again to let sit for an additional hour in the preheated tun. After this hour, the temperature was 167. I left the water in and put in a heat stick, heated the same water up to boiling, let it cool to 152, and waited a third hour. After that hour, the temp was 147. Granted, this was just with water and no grain, but still, at half-full capacity after two preheat steps + a boiling step inside the mash tun, I'd expect better heat retention.

I'll be brewing a batch tomorrow and am going to try heating my strike water slowly inside the mash tun with a heat stick as to preheat the tun as the strike water heats as I did in the experiment last night. Interested to see if this holds temp any better than just the water.

[ynotbrusum]

I have the 20 gallon tun.  I preheat with the strike water volume at 170F by filling the tun, drain, reheat as needed and underlet my mash.  However, I typically recirculate my mash, so temperature is not a huge issue if it is low, because it stabilizes at my set point within a few minutes.  Also the probe is in a thermowell, so it isn’t instantly stabilized - I give it ten to fifteen minutes and double check with a Thermapen.  Stirring well is important, especially when I don’t recirc, so I make sure not to open the lid during the mash, so as to avoid heat loss.  There can be cold spots, but underletting and good stirs usually even it out well enough and no unnecessary opening of the lid (just like cooking - leave the lid on or you lose heat!).

After a few uses you will get it down.  Cheers.

So I ran an experiment last night similar to the routine you've described. I heated up five gallons (half of mash tun volume) to 175 degrees and put in cold tun. I let it sit for an hour. After that hour, the water was 164. I drained, heated the water back to 175, and filled again to let sit for an additional hour in the preheated tun. After this hour, the temperature was 167. I left the water in and put in a heat stick, heated the same water up to boiling, let it cool to 152, and waited a third hour. After that hour, the temp was 147. Granted, this was just with water and no grain, but still, at half-full capacity after two preheat steps + a boiling step inside the mash tun, I'd expect better heat retention.

I'll be brewing a batch tomorrow and am going to try heating my strike water slowly inside the mash tun with a heat stick as to preheat the tun as the strike water heats as I did in the experiment last night. Interested to see if this holds temp any better than just the water.

Interesting to hear, but heat loss of water in the tun isn’t terribly meaningful to me - the thermal mass of a mash is more important to note in terms of temperature holding.  With the mash, I don’t see much loss over the typical one hour mash time on those occasions when I haven’t recirculated with HERMS.  Some loss, but only a degree or two, so it is sufficiently stable for me.  Cheers!