Mash Temperature Reading

[BigPerm]

Within the last year, I got back into brewing after after a 4+ year hiatus and upgraded my system at the same time.

When I moved from a 5 gallon cooler to a 10 gallon, I noticed that taking an accurate mash temp reading is unreliable, at best. I use 2-3 thermometers to try to get an accurate reading, usually a floating thermometer (alcohol) and an instant read probe). The temp differs between 3-6 degrees between the two. Last weekend, I made a saison where I'm reading 154 with the floater and 147 with the probe (which is a little higher). This is sensical because I mash in by underletting hot water from the HLT/kettle to the tun, but when I used to use a 5-gal mash tun I never had this issue. It makes getting an accurate reading quite difficult.

I usually split the difference and, if its in the ballpark, stop messing with it. The beer always ends up in the general ballpark of my expected FG, so my method is working, but theres got to be a better way to control and equalize my mash temp. (Plus, I'm a biochemist, and the microenvironments that could be caused by different temps drives me a little crazy...)

I'm just curious what others do. Is there an obvious better way that I'm missing? I lose less heat by underletting, but I'm not sure its the best way (at least with my system.)

Thanks.

 

[acidrain]

Stir.

 

[day_trippr]

Gotta love it

I use the 24" long version of this through a hole in the lid of my 10g Rubbermaid MLT. It's no "long stemmed Thermapen" (I wish!) but it's fast enough to find differentials - which may lead to that stirring thing...

Cheers!

 

[Roundhouse]

Get a pump and slowly recirculate for the entire mash.

 

[zachattack]

First I'd check both thermometers (in a proper ice bath as well as boiling water) and see if one is off, which is likely. Then stir

 

[blizz81]

How long is your insta-read probe? If it's not long / penetrating too much into your mash, if you really want to lose sleep at night with these minor thermal worries, get a longer probe and measure all around in your mash tun. Before I went RIMS, in both our $250 made-for-homebrewing gott-style-but-not-gott-cooler mashtun and in a wrapped sanke, the mash had pretty notable differences top to bottom and middle to side.

 

[william_shakes_beer]

As others have said, stir. The temps tend to stratify as the mash rests. That means initally the upper part of the mash will get warmer. I was going mad trying to figure out why my dough in temp of 157 was rising after 20 minutes to 160. Then I stirred and found the temp was right where I put it. Now I just dough in, set the timer and watch TV for an hour.

 

[BigPerm]

As others have said, stir.

Ok, ok. I set myself up for that...

The temps tend to stratify as the mash rests. That means initally the upper part of the mash will get warmer. I was going mad trying to figure out why my dough in temp of 157 was rising after 20 minutes to 160. Then I stirred and found the temp was right where I put it. Now I just dough in, set the timer and watch TV for an hour.

So, to provide more information, I mash in, stir the hell out of it, set my thermometers in and close up for 5 minutes to equilibrate. Then I stir again. And sometimes again. I have a long wooden paddle that gets all the way to the bottom. I get different readings throughout the entire mash, and both thermometers read the same (32-33F) in an ice bath.

 

[poptarts]

50$ ghetto herms solves all issues.

 

[Wynne-R]

I figure if the strike temp is right, the mash temp will be right.

The mash is chunky, and the sensor in the temp probe is tiny. I use an analog lab thermometer and it works pretty well. The bigger mass in the tip averages the temperatures.

Ideally you would attach the thermometer to the mash paddle. I wish somebody would market something like that.

 

[william_shakes_beer]

Ideally you would attach the thermometer to the mash paddle. I wish somebody would market something like that.

Or build the thermometer into the mash paddle. Digital readout in the handle, a series of 40 probes up and down both edges of the paddle, weighted averaging of the readings and a write to a 40 page spreadsheet that updates real time. Where's Tim Taylor when you need him!!!