Trouble Getting a Stable Mash Temp Reading

[mcgster]

Hey everyone, I’m hoping to get some help on an issue I have been having with my mash temps… well at least with getting my mash temps.

I was playing around with setting up a basic HERMS setup using my pump to recirculate water through a coil in my MLT and I was having a very hard time getting a stable mash temp. I was using the probe from my STC-1000, which I placed in the bottom portion of the mash and a handheld temperature probe (KM14 High Temp Pocket Digital Thermometer) to periodically take readings from the top of the mash.

I noticed that they were reading differently by a few degrees so I would stir the mash vigorously and take new readings. The temperature reading on the handheld probe would bounce around by several degrees 150, 153, 151, 156… etc..

I’m wondering two things 1) how do people ensure they are getting an accurate mash temp to drive their HERMS setup and 2) is it common for the readings to bounce around like this on the handheld meters?

Thanks!

[RubberToe]

First of all, did you calibrate both of those probes, or are you sure they will give the same reading on the same sample? There's an offset setting in the STC-1000 to adjust the reading. Also, the STC's probe may be watertight but I'm not so sure I'd want it in my mash. There may be alternatives there (ie: other j-type probe or whatever it is).

Sorry, I can't give much input on your handheld meter but mine seems pretty stable. I don't do HERMS either so can't be any help there.

Good luck.
-Rob

[mcgster]

Thanks Rob, I had calibrated them before and used the offset on the STC to adjust. I didn't calibrate last night so that could be part of the issue.

I forgot to mention that i also have a blichmann analog thermometer installed on the tun which reads stable but is very slow to change.

[RubberToe]

Do you know anyone with a thermapen? I was thikning about bribing someone with homebrew to bring it over so I can calibrate my 7+ thermometers / probes.

[mcgster]

Sadly no (i had to google thermapen lol) i was thinking about calibrating in boiling water / freezing water but i'm not sure how well that would work in practice (In theory it should work quite easily!)

[JohnnyMac]

Do you know anyone with a thermapen? I was thikning about bribing someone with homebrew to bring it over so I can calibrate my 7+ thermometers / probes.

I can swing by/spot you my Thermapen whenever you want it Rob.

[gm-]

Sadly no (i had to google thermapen lol) i was thinking about calibrating in boiling water / freezing water but i'm not sure how well that would work in practice (In theory it should work quite easily!)

Hey Mark, I have one of their cheaper thermalite models that you are welcome to borrow (Accuracy: ±0.9°F between -38.2 to 257°F), and I am pretty sure some folks in the Fundy Area Brewers have a thermapen.

Cheers,
Jon

[farmerwib]

Here's how Thermoworks recommends calibrating a Thermapen using an ice bath.
http://thermoworks.com/pdf/user_manuals ... ration.pdf" onclick="window.open(this.href);return false;

Obviously you'd use whatever mechanism is built into your thermometer to adjust it, but if Thermoworks recommends the ice bath, that's what I'd use.

[mcgster]

Hey Mark, I have one of their cheaper thermalite models that you are welcome to borrow (Accuracy: ±0.9°F between -38.2 to 257°F), and I am pretty sure some folks in the Fundy Area Brewers have a thermapen.

Cheers,
Jon

Awesome I was just looking at those models they seem much more reasonable.

When you use it to check your mash temp does it fluctuate or stays very close to a reading?

I'm wondering if my handheld probe is just a dud the way it bounces around.

[mr x]

Fwiw, I compared the cheap model to the Cadillac, and they read identical. Only difference was the speed.

Sent from my Nexus 4 using Tapatalk 4

[LeafMan66_67]

Fwiw, I compared the cheap model to the Cadillac, and they read identical. Only difference was the speed.

Sent from my Nexus 4 using Tapatalk 4

Same results here. Thermapen is quicker but temperature readings are the same. The advantage of the cheaper one is that it is waterproof - it has been accidentally IN the mash tun a number of times with no adverse effects.

[gm-]

Awesome I was just looking at those models they seem much more reasonable.

When you use it to check your mash temp does it fluctuate or stays very close to a reading?

I'm wondering if my handheld probe is just a dud the way it bounces around.

It stays very close, usually very stable after the 2-3 second it takes to get a reading, and like Leafman said, those cheaper ones are great and waterproof. I even dropped mine into the boil kettle once without harming it.

[mcgster]

Thanks! Sounds like my wish list just got a little bit longer.. Although this one may be moved to the top.

[bluenose]

I made a wrist strap for my thermopen in case I dropped it into the boiling wort