Cheap, unreliable dial thermometers

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Elrond

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I have two brewing dial thermometers that I have equally calibrated with ice water. When I reach mash temp they show different numbers ± 4°F . So I try to keep one thermometer at 148 and one at 152. So at ~150, I stir, turn off the flame, and put the lid on. 20 minutes later I stir it and measure it again, and it's almost 160 °F. Then my beers end up with a high FG and a residual sweetness.
 

matt_m

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The Blichmann ones seem to be of good quality. I use one on the output of my chiller and it seems to agree closely with the temps shown on controllers on my fermenters.
 
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Elrond

Elrond

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The Blichmann ones seem to be of good quality. I use one on the output of my chiller and it seems to agree closely with the temps shown on controllers on my fermenters.
The Blichmann screws in... How do I screw that into my stock pot.
 
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Elrond

Elrond

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The Blichmann ones seem to be of good quality. I use one on the output of my chiller and it seems to agree closely with the temps shown on controllers on my fermenters.
This hobby really does require investment...
 

matt_m

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Ah, I was picturing the typical kettle thermometer. If you are talking handheld, digital is the way to go. There's the Thermapen and then there's everything else. This Inkbird is a good budget buy.

The temperature increase is probably a different issue.
 

eric19312

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I have had great luck with these

Probably bought 4 over last 7 years they don't last forever but they are fast and accurate.
 

eric19312

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Let me add...if you can find a decent accurate thermometer use it to calibrate your cheapos to read 150F correctly. You will probably be within a degree or so at mash temps that way and thats all that really matters in this application.
 

CascadesBrewer

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I have a $20-$30 long stem brewing thermometer that I like (Fermentap brand), but it can drift out of being accurate (and one day it was off 10F during a mash!). I picked up a cheap digital thermometer that just did not handle the damp conditions of brew day (even after the manufacture sent me a replacement which died as well...I would definitely at least get one that says it is waterproof/resistant).

So...I have an inexpensive glass lab thermometer that I use on brew day to verify that my long stem thermometer is accurate before the mash. I got it at my local brew store, but I see plenty on Amazon for $10 to $12. I suspect there is a chance one of these is off, but mine has been accurate when tested with ice water and boiling water. It is slow to read and fragile, so it does not make the best general purpose thermometer.
 
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Elrond

Elrond

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Thanks for the suggestions.
I've decided to go with CascadesBrewer's advice and get a glass lab thermometer to use for calibration at mash temp.
 

IslandLizard

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I have had great luck with these

Probably bought 4 over last 7 years they don't last forever but they are fast and accurate.
For $20 this is a great thermometer, used one for many years! ^
Amazon has them too.

There's the Thermapen and then there's everything else.
Agreed, I bought one 10 years too late.
Eventually I succumbed to the temptation, and bought a Thermapen Mk4. There's simply no comparison in speed and accuracy.
It was an "open box" sale. You need to sign up for their emails to get the special deal alerts.
 

IslandLizard

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So at ~150, I stir, turn off the flame, and put the lid on. 20 minutes later I stir it and measure it again, and it's almost 160 °F.
You didn't stir thoroughly enough. You need to turn the mash over, bringing the bottom of the mash up.

When your strike water is at the right volume and temp, there's no need to apply heat after (thoroughly) mixing, you'll hit your intended mash temp right on the nose. It may take a brew or 3 to adjust for your equipment and environment.

Now if you're outside, the weather plays a big role too. Sunny summer brewing is very different from being in a winter blizzard.
Insulate!
 

InspectorJon

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ThermoPop is a less expensive option to the ThermaPen. $34 vs. $99, made by the same company. It’s takes a couple extra seconds to read temperature and is moisture resistant rather than waterproof. I’ve had one for several years now and it works great.
 

Birrofilo

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I have two brewing dial thermometers that I have equally calibrated with ice water. When I reach mash temp they show different numbers ± 4°F .
If you can calibrate your thermometer then you should calibrate them at the temperature which is most important to you, in the range that we care most, which is from 55°C which is a possible mashing step when using moderately modified malts to 78°C which is the usual mash-out temp.

That means borrowing a trusted and precise thermometer only once.

Your calibration temperature should either be 63 °C - 145 °F which is a typical monostep mashing tempearture or a bit higher, 66,5°C, halfway in the abovementioned range. That should guarantee a high accuracy even with a cheap thermometer.

That said, I use this cheap thermometer:


€16, gives a correct answer within a few seconds, decently splashproof, auto on auto off, very useful for all sorts of measurements such as water for hydrating dry yeast which I warm up with the microwave oven, or to check mash temperature at different points of the kettle (which gives quite discouraging results... don't do that, ignorance can be a bliss ;) ).

Generally speaking I am surprised by how coherent the various thermometers I have are, and how variable is the mash temperature in various spots of the mash. Mash uniformity is IMHO a much greater problem than thermometer accuracy.
 

Jim R

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Mash uniformity is IMHO a much greater problem than thermometer accuracy.
Completely agree with this. I don't depend on any temperature reading (mash, water and boil kettles, etc.) unless I have stirred well and checked with a handheld thermometer in a representative part of the vessel.
 

Bobby_M

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Bimetal dial thermometers are just about all equally slow and inaccurate no matter what you pay for them. No, I'm not saying there is no quality difference between $20 and $100 brands, as build quality does vary abut that's more about the case and lens. It's the physical method of a bimetal strip expanding and contracting that makes them +/- 2% of the temperature range. TLDR:Digital wins
 
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Elrond

Elrond

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Calibrated my dial thermometers using a glass lab thermometer at water temperature 150°F. They were 5-7°F over, which would explain my high FG readings.
 
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