Measuring temperature of mash - problems?

[SatanPrinceOfDarkness]

I have a thermometer I use for all my brewing purposes. It's made by ThermoWorks. Unfortunately I can't find this model online, but I bought it at the LHBS. It's a simple pen type yellow/black thermometer with an on/off button, C/F button, and 6" metal probe.

I'm doing BIAB, and this is only the 3rd I've done. That said, I've also steeped grains before in extracts and of course I use the thermometer for measuring rehydration water, cooling wort, etc.

In all these scenarios, I see minimal variation as I move the probe around in the water, especially after I've stirred. When steeping grains I notices that the center of a tightish grain-bag would be a little cooler than the surrounding water, but that's it.

All that went out the window last night with my mash. After the infusion and stirring, it kept varying by a few degrees as I moved it around. OK. Then, when I went to mash out to 170, it just was going crazy. It seemed not to be moving at all, and then suddenly I was getting temperatures varying from 160 up to 195. This whole time I had been stirring. I noticed that when I was moving the thermometer around a lot it seemed to jump up in temp, but I haven't been able to reproduce that in any way since, not even when boiling the sweet wort.

All my other temperature measurements seemed to work fine after that.

Anyone have an issue like this? Any steps to solve it? I've got to be able to measure the temperature of the mash.

 

[gotbags-10]

If you tested your thermo in boiling water and its stable then try using s bigger bag for the grains. You don't want a tight grain bag.

 

[SatanPrinceOfDarkness]

If you tested your thermo in boiling water and its stable then try using s bigger bag for the grains. You don't want a tight grain bag.

Yup, tested at 212 and stable.

My bag wasn't tight at all. I mentioned tight bags from when I would steep grains for extract brewing and to demonstrate my experience measuring varying temperatures. My current bag is big enough to fit the 10 gallon pot inside. I had its edge clipped to the top of the kettle, and it filled the kettle fully.

 

[Frilock]

how did you raise temp for mashout?

 

[SatanPrinceOfDarkness]

how did you raise temp for mashout?

I turned the burner on, about medium because I didn't want it to raise too high by accident. I thought about adding hotter water, but I was aiming for single vessel brewing this time.

 

[Frilock]

temp strat. gets me every time. really gotta make sure you stir.

 

[madscientist451]

Adding hot water to raise the temp is much more reliable and easier to avoid temperature swings.
Use the rest calculator at the greenbay rackers website.
Maybe get another thermometer if you are suspicious of the one you have. I have a simple dial thermometer with a 9" probe, think it cost $10 at the LHBS. Hasn't given me any trouble.

 

[RM-MN]

I have a thermometer I use for all my brewing purposes. It's made by ThermoWorks. Unfortunately I can't find this model online, but I bought it at the LHBS. It's a simple pen type yellow/black thermometer with an on/off button, C/F button, and 6" metal probe.

I'm doing BIAB, and this is only the 3rd I've done. That said, I've also steeped grains before in extracts and of course I use the thermometer for measuring rehydration water, cooling wort, etc.

In all these scenarios, I see minimal variation as I move the probe around in the water, especially after I've stirred. When steeping grains I notices that the center of a tightish grain-bag would be a little cooler than the surrounding water, but that's it.

All that went out the window last night with my mash. After the infusion and stirring, it kept varying by a few degrees as I moved it around. OK. Then, when I went to mash out to 170, it just was going crazy. It seemed not to be moving at all, and then suddenly I was getting temperatures varying from 160 up to 195. This whole time I had been stirring. I noticed that when I was moving the thermometer around a lot it seemed to jump up in temp, but I haven't been able to reproduce that in any way since, not even when boiling the sweet wort.

All my other temperature measurements seemed to work fine after that.

Anyone have an issue like this? Any steps to solve it? I've got to be able to measure the temperature of the mash.

Yes, your mash temp will vary a bit as you move the thermometer around in the mash. Even if you stirred it very well, the temperature in the center of the mash will be lower than at the outside. I'm not sure why, I just noticed it like you did. Iif it bothers you too much, stir the mash. Otherwise just ignore it. If your grains are milled fine for BIAB, the conversion will be over before you even notice the temperature change.

You can avoid the big temperature swings during mash out very easily. Don't do a mash out. Yep, that simple. Mash out only applies to a conventional mash tun, not BIAB and then it only applies when you are doing a fly sparge in the conventional mash tun. The reason you do a mash out when fly sparging is to denature the enzymes before you start the fly sparge so that the time spent sparging doesn't let the enzymes continue to convert sugars. Since you aren't using a conventional tun and not fly sparging, you don't mash out. You pull the bag of grains out, turn on the heat to bring the wort to a boil while the bag is draining and that heats the wort to the point that the enzymes are quickly denatured.