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BIAB mash profiles and "Adjust Temp for Equipment"

cmbrougham

Grandmaster Brewer
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Previously, I only did AG mashes in my cooler-based MLT, and the MLT and grain are kept out in my garage, which during the winter puts them both around 35-40dF. In that case, I use the "Adjust Temp for Equipment" checkbox in the Mash tab to account for these temperatures, and to get the strike water at the right temperature for my desired mash temperature. The "Adjust Temp" checkbox seems to utilize both mash tun temperature and grain temperature (both under "Mash Initial Conditions") in calculation of strike temp. So far, so good.

I've done several BIAB batches now, and have consistently been missing (usually by overshooting) my desired mash temp by 1-3dF, depending on how cold the grain was and whether I'm mashing for light, medium or full body. As before, I'm using "Adjust Temp" checkbox along with my grain temp; however, I'm leaving "Mash Tun Temperature" at the default, which I believe is 72dF in the shipping profiles. Really, though, this is incorrect: my mash tun, which is the kettle I'm using to BIAB, is at the same temperature (or near to it) as the water being heated within it.

So, what's the correct way to deal with this? I'd be tempted to call this a bug, since it would seem that the initial MT temperature shouldn't be a factor in calculating strike temp when doing BIAB, but I suppose there are some who do a hybrid-BIAB and use something like a cooler to mash in along with the bag. In my mind, if I've selected the "BIAB Mash with Full Boil" in the Mash Profile designer, the MT temperature should be discounted from the strike temp calculation. I suppose I can fake it by punching in a Mash Tun Temperature that is a few degrees higher than my desired strike temperature, but this seems a bit... dodgy. I actually did this on a BIAB batch I did yesterday, and got much closer to my desired mash temp.

Thoughts are appreciated.
 
For my BIAB profiles, I use a standard single infusion profile.  I click off the adjust temperature for equipment, so that the program figures the temperature for just the water and grains added.  My grains are stored in a refrigerator just prior to addition, so they are also at a temperature of around 45F by the time I bring them in and pour them into the bag. 

I have consistently been within a degree or two of my target, which given the variable temperature of the grain and the timing between reaching strike temperature, loading and stirring, I consider pretty good.

 
What about putting the correct temperature in the tun temperature box. Have you tried that at all yet?
 
I tried that at first and found that it was an iterative process to get the temperatures to come close (equipment temp vs. strike water temp.)  Easier to turn teh adjust equipment for temp off and let the program figure the water temp/grain temp calculation, ignoring the equipment.  Within a degree or two for mash temp, I don't sweat it.  My process and handling can lead to that type of variability in itself.  As long as the error is random, and I do track and record the temperatures, I figure the program is doing it's part well. After all, it doesn't know that I took the grains out of the fridge a few minutes early or that I started before building a fire in the wood stove so the kitchen temp is 60 rather than 70.
 
Thanks guys, for the thoughts.

Oginme: I used your modified BIAB/infusion mash steps for the first couple of BIABs I did, and while I got good results, when I did a straightforward BIAB for comparison, I had pretty much the same efficiencies, with a bit less work. I've stuck with the single-vessel, single-step (though I do raise the kettle temp for a mash out) in the 3-4 batches since then, and have been hitting 80-83%, and I'm satisfied with that. The one thing I've noticed--and maybe this is just some placebo effect--is that the BIAB brews seem lighter in body at a given temperature than when doing a more traditional infusion mash in my cooler-based MLT setup.

Now, admittedly, a few variables have changed, not limited to just the BIAB process vs. infusion mash. I've started using a much more accurate thermometer, used domestic base malts where I more typically use British base malts, adjusted my malt mill grind, and a few other things--so this is not a scientific evaluation whatsoever. It's either that I'm more accurately hitting my mash temps now whereas before I was creating less fermentable worts on either side of the range, or, it might just be that I'm being hypercritical! A few brews I've done BIAB that I thought were too thin, my in-home beer critic (aka my wife) said they were too heavy. So, maybe there's just no accounting for taste!

As it is, I've realized that adjusting the initial grain temp with or without the "Adjust Temp for Equipment" box checked does change the strike temperature. I'm not sure why I thought this was NOT the case before, but it did lead me to realize that with the "Adjust Temp for Equipment" box checked and the mash tun temperature set to your desired mash temp, e.g. 148dF, that I get exactly the same strike temp as if I don't use the "Adjust Temp" box, all other factors being equal. I've always used the "Adjust Temp" box as I've historically always mashed in the cooler MLT--old habits die hard. So for now, I think I'll follow your suggestion and just leave the box unchecked, and input the grain temp shortly before mashing in--I put a probe thermometer into the bucket of malt to get this temperature. With those steps, I think I should be more accurately reaching my desired mash temp with minimal fuss.

Thanks for the insights!
 
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