All-Grain Thermometer Question

[wvbrewed]

I'm a couple of batches into all-grain brewing and while most everything's gone fairly well I have some suspicions about the accuracy of the mash tun's screw-in / twist-in dial thermometer I use versus a digital thermometers or a standard glass thermometer placed in the mash. The dial thermometer only goes about two inches into the mash.

Just wondering what everyone else finds reliable or if most would advise using a digital thermometer in addition to the dial thermometer. Hoping this will help me really fine tune my mashing temps in future batches. Any help or advice is greatly appreciated.

 

[m1k3]

My HLT has a Blichmann Brewmometer and at this point I can hit my mash temp pretty close just by heating my water to the appropriate temperature.

I do check the mash temp using a digital thermometer.

Once a year I calibrate my digital thermometer with a glass of crushed ice water (per the instructions that came with my thermometer) and then ensure the analog thermometers match that.

 

[Izzie1701]

I use my I grill probe and stick it on the middle of the mash. Seems accurate and my phone alarm goes off if it drops low

 

[cannman]

Don't forget to calibrate it. The one in my pot has a little dial to adjust.

Keep in mind that the temp will be different at the bottom of the pot vs where the thermometer is mounted vs the top. So I use this in conjunction with the thermometer:

My best advice is: once calibrated, your temps may still be off. But it is important to know how your equipment behaves. If you want to brew a beer that says to mash at 154f but you know your equipment lags a few degrees then mash when YOUR equipment says 152f etc. but after ice water calibration and the laser thermometer you should be solid.

 

[SGTSparty]

Don't forget to calibrate it. The one in my pot has a little dial to adjust.

Keep in mind that the temp will be different at the bottom of the pot vs where the thermometer is mounted vs the top. So I use this in conjunction with the thermometer:

-Image Removed-

My best advice is: once calibrated, your temps may still be off. But it is important to know how your equipment behaves. If you want to brew a beer that says to mash at 154f but you know your equipment lags a few degrees then mash when YOUR equipment says 152f etc. but after ice water calibration and the laser thermometer you should be solid.

Question on this. Does the laser thermometer measure below the surface?

I have pretty unsophisticated all grain system and I tend to struggle w/ the same worries as the OP and as you said my Mash Kettles thermometer is near the top of my grist and that's only because of the false bottom. I try to combat that by pulling some liquid from the ball valve and measuring that and recirculating it to the top to try and hit an equilibrium but I've been debating a laser thermometer as well but have been wondering if it too would only measure at the top off the liquid/grains.

 

[govner1]

The laser cannot/will not measure grain bed temps or enable you to compensate for the inevitable temperature gradients within your MLT.
I use a long probe thermometer from Cool-Rite. It is very accurate and allows me to measure several areas within my mash. Stirring frequently will help you have more stable temps throughout by helping eliminate cooler areas due to gradients.
Probes through the MLT wall are nice but don't give you an accurate picture of what is really happening. Also, I've found that my Blichmann thermometers are horribly inaccurate. I cannot even rely on the one on my HLT. Once again I use my Cool-Rite when heating strike/sparge water.

 

[JONNYROTTEN]

Every thermometer gave me a different reading,tested at the same time in the same place AFTER calibrating.It drove me nuts.I finally gave up and now I just use my Inkbird off the ferm chamber with the probe in the grain bed..Aint gettin any more accurate than that

 

[ajdelange]

The big problem with getting mash temperature is that it is very hard to mix it uniformly. If you have a thermometer with a probe that you can poke around in the mash try that. You'll be amazed at the temperature gradients you will see. For example, in an uninsulated SS pot the mash near the walls cools much faster than the mash at the center.

With the non contact thermometers the problem is the emissivity. It is much lower for SS than for mash. The better ones allow you you to set emissivity but a simpler approach is to stick a piece of electricians tape on the side of the pot. It has about the same emissivity as mash and temperature readings will be much more accurate.

 

[bonecitybrewco]

Thermapen and don't look back.

 

[ajdelange]

The problem with Thermopen's is that they are Type K thermocouples and subject to the level of accuracy that a Type k thermocouple can deliver. Of course that's about the level of accuracy I would expect from a bimetal dial thermometer. As long as it is repeatable I guess that's what's important.

 

[cannman]

Question on this. Does the laser thermometer measure below the surface?

I have pretty unsophisticated all grain system and I tend to struggle w/ the same worries as the OP and as you said my Mash Kettles thermometer is near the top of my grist and that's only because of the false bottom. I try to combat that by pulling some liquid from the ball valve and measuring that and recirculating it to the top to try and hit an equilibrium but I've been debating a laser thermometer as well but have been wondering if it too would only measure at the top off the liquid/grains.

My understanding of the technology is that the laser will read the infrared output of the surface. Have you ever seen the movie Predator?

So you figure the temp of the dial thermometer and consider the laser temp and call it a happy medium.

For what it's worth, after a lengthy talk with my LHBS owner, we figured that the BEST way to take a temp is to recirc the mash and take a temp from the tube using an inline thermowell and then laser the output spray from the mouth of the recirc return valve. (That's some real insider $hit right there) :rockin:

 

[ajdelange]

My understanding of the technology is that the laser will read the infrared output of the surface.

We do all understand that the laser doesn't do anything except show us where the IR detector is pointed, right? The IR detector measures the intensity of the infra red radiated by whatever it is pointed at and display the temperature of the perfect black body radiator that produces that much as adjusted by the emissivity which is the ratio of the actual body's emission to that of the perfect black body. I'll be bold and say that, given the thermometers emissivity is set correctly, it measures the temperature of a layer that is a couple of wavelengths thick.

For what it's worth, after a lengthy talk with my LHBS owner, we figured that the BEST way to take a temp is to recirc the mash and take a temp from the tube using an inline thermowell and then laser the output spray from the mouth of the recirc return valve. (That's some real insider $hit right there) :rockin:

That will measure the temperature sensed in the tube, not the temperature of the mash which, as I noted earlier, can be astonishingly different depending where in the mash you measure it. IOW the mash does not have A temperature. It has dozens of different temperatures.

 

[0wly055]

I grind my grain so fine my mash is done within 4 minutes, no need to hold stable temps if you ask me.

 

[brandonnys]

I grind my grain so fine my mash is done within 4 minutes, no need to hold stable temps if you ask me.

What? Teach me your secrets. How do you extract all the sugars in four minutes? Quickest I've heard of is 20 minutes.

 

[cannman]

We do all understand that the laser doesn't do anything except show us where the IR detector is pointed, right?

It is IMHO that the laser is more of an attempt to satisfy human consideration to where the tool is pointing and thus reads overall IR radiation based on that point, and you should contact the manufacturer of your laser thermometer for the exact specifics of what it's reading parameters are.

That will measure the temperature sensed in the tube, not the temperature of the mash which, as I noted earlier, can be astonishingly different depending where in the mash you measure it. IOW the mash does not have A temperature. It has dozens of different temperatures.

So, the POINT of the post (forgive me if it was too abstract for you) is to understand that you CAN NOT measure the EXACT temp of the entire mash as a whole due to depth, source of the heating element Etc. Etc. Etc. BUT CAN discern a relatively accurate measure of mash temperature if BOTTOM wort temp is taken and then TOP temp is taken and then averaged to arrive at some arbitrary figure to satisfy the anal homebrewer. An understanding in basic comparative arithmetic, not advanced mathematics, should have your arrive at a similar conclusion.

 

[DurtyChemist]

Thermapen and don't look back.

This. NIST traceable so it's been certified against industry standards. It works great for cooking too. You could also put a glass floating one in the mash and compare that to your probe thermometer.

 

[Horseshoot]

Here are my thought (for what they are worth): Find a thermometer you like, and stick with it. Keep it calibrated (unless you can't calibrate it) and then adjust your temps, over time, based on your results. In other words, dial it in to your system. A number really means nothing. It is consistency we are after, right?
BTW, I calibrate my digital thermometer every brew day.

Mike

 

[blizz81]

The big problem with getting mash temperature is that it is very hard to mix it uniformly. If you have a thermometer with a probe that you can poke around in the mash try that. You'll be amazed at the temperature gradients you will see. For example, in an uninsulated SS pot the mash near the walls cools much faster than the mash at the center.

For me, if you can get this picture (even if you're just borrowing from a friend / another brewer / etc) a couple of times (for example, a 60 min mash with no stirring, and then maybe a mash where you stir a couple times), it is ideal to get a good view of what's going on with your equipment.

 

[Drk93TT]

Thermapen and don't look back.

Yep !

 

[jmill]

Thermapen and don't look back.

3rd'ed. Works great for beer and brisket.

 

[Yesfan]

Love mine. Only regret is not getting the backlit model. I want to get that Trio timer they have out now too.

 

[Saboral]

Don't forget to calibrate it. The one in my pot has a little dial to adjust.

Keep in mind that the temp will be different at the bottom of the pot vs where the thermometer is mounted vs the top. So I use this in conjunction with the thermometer:

My best advice is: once calibrated, your temps may still be off. But it is important to know how your equipment behaves. If you want to brew a beer that says to mash at 154f but you know your equipment lags a few degrees then mash when YOUR equipment says 152f etc. but after ice water calibration and the laser thermometer you should be solid.

Be careful here, many of these temperature "guns" have a resolution of +/-5 F. I have many inspectors using them for asphalt testing.

 

[govner1]

Get one of these: http://www.restaurantsupply.com/cooper-atkins-ttm41-0-8

The long probe will give you the ability to better measure what's going on in your MLT.
Very reliable.

 

[thunderwagn]

I've also got a Cooper Atkins. Great thermometer for the $.
http://www.amazon.com/dp/B000LDE0QQ/?tag=skimlinks_replacement-20

 

[bonecitybrewco]

3rd'ed. Works great for beer and brisket.

Really, is there anything more to life than beer and bbq?