Mash temp with BIAB

[SPav]

I have a 10 gallon Bayou Classic which included a dial thermometer about 5 inches from bottom. I also have a Javelin Pro digital. While heating to my strike temp (158F) both thermos were within a degree of each other. But once I added my grains, I was reading 150F with Javelin but the BC thermo was reading 158F, even after a good stir. Which temp should I be using for mash, top of kettle with Javelin or bottom of kettle with BC dial?

 

[wilserbrewer]

I would use the digital. I don't prefer kettle mounted dial thermometers for BIAB, seems people forget they are there, snag the bag and keep yanking...

 

[Chris_Primavera]

Have you calibrated either?
(Ice water at 32°F and boiling at 212°F ± altitude adjustment)

I would trust the digital as the bulkhead thermo may be influenced by the kettle mass.

 

[BowAholic]

My digital (thermoworks) has a 12" probe... I also use a 10.5 gallon kettle for BIAB... I have noticed quite a temperature difference from top to bottom when doing a full volume, 7.5 gallon, mash. Seems like if I drop the thermometer thru a small hole in the lid and allow it to sit near the bottom until I get my 152* temp, if I raise it until it's only about 4" into the mash the temp is 3-5* warmer, which is not what I want. I hope someone chimes in that knows, but I have decided to just let it rest in the lid hole and only let it get maybe 148 towards the bottom, so that I have my 152* towards the top. ... and yes, I stir frequently.

 

[dmtaylor]

When in doubt, take the average. Also calibrate your thermometers and find out which is more accurate.

 

[wilserbrewer]

I take the temp while stirring and swirling the mash from the bottom up and assume that to be the average temp.

I only take temp immediately after or during a stir. Also, you should be stirring long enough that the temp is consistent throughout.

 

[Rhaop]

Best thing i've found to do with full volume mashing is to try and pull as much grain up from the bottom of your kettle/mash tun while you stir, I hope i can explain this right but when i first started biab my first couple beers were kinda low on efficiency and highly attenuated, during the third batch while i was stirring the mash about 15min in i was kinda stirring back and forth well I decided to try and bring some grains from the bottom up to the top "just to see" and i noticed that even after stirring a lot after 15 min that the bottom of the mash had an inch or two of grain that kinda compacted and i was almost just stirring above it without realizing

Not saying you aren't stirring good enough but just my ideal that you could try to stir upward if that makes sense because my guess is that my first couple bacthes i missed some grain at the bottom and it had cooled off 5-6* from the rest of the mash

I usually take my measurements from the top 4-5" cover my kettle with an old sleeping bag and stir every 15min, i do mash higher now then I did with a three vessel batch sparge set up


Edit: wilserbrewer beat me to it and said it best lol, stir from bottom up

 

[SPav]

I did stir multiple times during the mash and I was stirring from the bottom as best I could, knowing that it seemed to be holding more heat. The temps matched between the two thermometers up until the time I added the grains. Once I got to boil the temps matched again, so I do not think it is a calibration issue.

If I have a 8 degree difference between top/bottom of kettle, how in the world do I manage my mash temps? For the record, I had 8 gallons of water and 12.75 lbs of grains.

 

[Murphys_Law]

I have the same problem with a kettle mounted BC therm. Drives me nuts. I stir well and can't get them in sync with the grain in the kettle. I use my digital for checking temps now.