Temp Probe in Thermowell Off

[lagavulin]

Hey guys,

I have a single tier HERMS setup with Keg vessels (photos below)

I have a 3'' thermowell in my mash tun and learned today that temps read by my probes are massively inaccurately.

I learned this by boiling my mash (I used direct fire to help bring my temps up following dough in) as the temp probe read 145 F on Dwyer love controller (TS-13010).

I've scrapped the brew as it took me awhile to figure out what was happening.

Anyway. I took the same temp probe and inserted it into my HLT thermowell (5'' long) and the reading was accurate.

So, what's the deal? Is a 3'' thermowell too short for an accurate reading? Are thermowells less accurate when inserted into the mash?

I plan to do a more thorough assessment of the probes tomorrow (after I calm down -- I read the method to calibrate is to use the P1 parameter adjustment. Is the most accurate way to calibrate ice water?

 

[Rapt0rBrown]

I am having the exact same problem. Mine even relays the correct temp around 100, but as i go higher, it becomes less accurate. Anyone have any suggestions?

 

[lagavulin]

I'm pretty sure mine was accurate until I added the grain as the MLT and HLT differed by a degree (HLT being hotter).

 

[l3asturd]

From what I've read the best way to calibrate is in the temperature range that you'll most often be using. I guess this would mean purchasing a lab thermometer and calibrating based on that at about 160F. I haven't done it yet but I want to.

Currently my temp probe is way off. My BK boils at 195F. My issue is length, it's reading stagnant water temps near the edge of the pot, so I'm ordering a longer probe. I also recirc. during all stages.

 

[lagavulin]

Well, I tested my thermowell and probe against my "instant read' (no name brand) and they were within 3 degrees of each other @ 100 F --- though it did take the probe 10 mins to get to the correct temp.

Then I tested the probe in ice water. Both the probe and the instant read, read 32.5 F

Maybe I need to thin my mash. Next brew I'll throw in an extra gallon of water or use 2 quarts per lb of grain.

I have to say it's a bummer to have an automated brewery that's not automated.

 

[coldrice]

Arrgghh! Alas, i am having the same problem. I'm using a thermowell in the ball valve ov my MT, recirculating the mash through a coil in the HLT back to the lid of the MT. The temp control reads 18 degrees lower than true temp using a 2.5" thermowell and about 6 degrees below true temp using a 6" thermowell (and i can't even close the ball valve). I've thought about insulating it, but it seems kinda desperate. Considering drilling a new hole and inserting the theremowell between the ball valve and the thermometer, but I don't really want to, as i know it will make my pump kick off sooner, which would be undesirable. Right now I am just figuring out the variable between the read out on the ETC and the thermometer. Pretty annoying!

 

[lagavulin]

Just an update I thinned my mash to 1.8 quarts per lb grain and my temp readings were more accurate and stable. The temp sensor in the thermowell was about 3 degrees off - but that's easily compensated.

I will be closely monitoring the temps over the next few brews to see if they are consistently off by 3 degrees -- hopefully so, and I'll adjust the target temp accordly.

 

[BargainFittings]

Curious if any of you use thermal grease in your thermowells?

 

[coldrice]

I am going to pick up some grease (I guess at Radio Shack?). I'm considering abrading the probe of the thermowell and dipping it in molten copper, also.

 

[aquenne]

off topic, but what is that gizmo with the red hose? some kind of oxygen machine? looks pretty hardcore..

 

[lagavulin]

It's a medical oxygen concentrator - it concentrates room air to pure O2

 

[coldrice]

off topic, but what is that gizmo with the red hose? some kind of oxygen machine? looks pretty hardcore..

pretty sure it's an old pace maker from the 1960s...