MoodyCopperpot
Active Member
I was thinking of investing in one of those laser or infrared thermometers. Does anyone know how accurate they are? Or a certain brand to get over another one?
Laser/Infrared Thermometers
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ultravista
Well-Known Member
I have a Fluke model 62 MINI, it is very accurate.
If you are interested, I have two simiilar gun-style laser thermometers I'd sell. Both take 9V batteries, both are accurate.
Ray
If you are interested, I have two simiilar gun-style laser thermometers I'd sell. Both take 9V batteries, both are accurate.
Ray
CaptYesterday
Well-Known Member
I have that I bought on Amazon awhile back (think it's the one Alton Brown uses occassionally on Good Eats). I had mixed results with it and stuck with my dial thermometer.
I played around with it during a brew, but when I tried to shoot a temp from my mash tun it read 130-something. I tried again and got the same result. I stuck my dial thermometer in the mash and it read 152.
My guess is that the surface temp of the mash was in the mid 130s (it's cold in Cleveland this time of year) but in order to get the actual temp, I had to go back to my other thermo.
I wouldn't recommend an infared thermometer for mash temp, but I use it frequently to check on the temp of my carboys. And to check the temp of whatever happens to be within 25 ft of me.
I played around with it during a brew, but when I tried to shoot a temp from my mash tun it read 130-something. I tried again and got the same result. I stuck my dial thermometer in the mash and it read 152.
My guess is that the surface temp of the mash was in the mid 130s (it's cold in Cleveland this time of year) but in order to get the actual temp, I had to go back to my other thermo.
I wouldn't recommend an infared thermometer for mash temp, but I use it frequently to check on the temp of my carboys. And to check the temp of whatever happens to be within 25 ft of me.
I've got a laser thermometer but don't consider it to be very reliable/accurate.
I bought the $25 one at Harbor Freight and the thing is spot on.
I just recently bought a combination Infrared and type-k thermocouple from American Science and surplus for $40. It is awesome and it has programmable emissivity for the infrared.
I use mine for work only (shooting bearings, motors, gearboxes and stuff like that) its accurate for situations like that. For liquids it only tells surface temperatures, so for it to accurately work you would have to stir the liquid fairly well to bring the surface temperature up to the same as the internal. So some cases it will work some I would trust it.
Jon, do you typically brew darker beers when you use this?
No, I use it to shoot the temp of anything. I even pointed the thing into my pool and it came up the same temp as my pool equipment was reading. I find it pretty accurate.
I use mine on water that is heating and I find it fairly accurate given that you stir well first. It doesnt just have to be dark beer.
Surface_Tension
Well-Known Member
You have to watch what you are trying to take a reading of as the accuracy of these devices depends on the emissivity of the material. Emissivity is just the opposite of reflectivity, so most polished metal will have a very high reflectivity but low emissivity, making them very difficult to measuring using a thermal gun or camera. To get around this, if possible, you can put some electrical tape on the surface and measure the temp of it. Electrical tape is highly emissive. So is water which is why his pool water measurements were accurate.
I do not have a table that lists the emissivity of a bed of mash, sorry. LOL
I do not have a table that lists the emissivity of a bed of mash, sorry. LOL
pj_rage
Well-Known Member
I have had mixed results with IR guns. They seem to be pretty accurate in general, probably +/- 1F, and you have to remember that it's surface temp, so as mentioned, it's not great for measure mash temp.
The thing that makes me not trust them the most is that they seem to get saturated and then read different temps. This seems to happen when reading something hot, ie a boiling pot of water or anything else pretty hot. You can measure your floor or something stable, get a reading that seems about right, measure the boiling water or something hot for a few seconds, then measure the ground again and it reads a different (higher) reading, depending on how hot the item was and how long you aimed at it, it could be just a few degrees higher or 10+. You can get around it a little bit by only aiming at the hot items for very brief periods of time, but I hate that I can't trust it 100%. It's fine to get a good general idea, but for any kind of reasonably accurate measurements, I want something I can trust. Even though they are pretty consistent around room temp, just the fact that I've seen them be inconsistent by 10+ degrees after taking readings makes me not trust it. They definitely serve a purpose and I love having mine, but you just need to understand the limitations and be careful if you need any kind of actual precision measurements.
One other thing is to pay attention to the spread of the beam. It is usually printed on the side of the device, usually somewhere between 6:1 and 12:1 from the ones I normally see. This will mean that the beam is about 1" diameter for every 6 or 12 inches of standoff. So if you have an 8:1 unit and measure from 2 feet away, you are measuring an average from a 3 inch diameter, not just the little dot from the laser. The further you can stand off, though, I would guess the less the effect of the saturation I mentioned above. I haven't really played with this to be certain, though.
The thing that makes me not trust them the most is that they seem to get saturated and then read different temps. This seems to happen when reading something hot, ie a boiling pot of water or anything else pretty hot. You can measure your floor or something stable, get a reading that seems about right, measure the boiling water or something hot for a few seconds, then measure the ground again and it reads a different (higher) reading, depending on how hot the item was and how long you aimed at it, it could be just a few degrees higher or 10+. You can get around it a little bit by only aiming at the hot items for very brief periods of time, but I hate that I can't trust it 100%. It's fine to get a good general idea, but for any kind of reasonably accurate measurements, I want something I can trust. Even though they are pretty consistent around room temp, just the fact that I've seen them be inconsistent by 10+ degrees after taking readings makes me not trust it. They definitely serve a purpose and I love having mine, but you just need to understand the limitations and be careful if you need any kind of actual precision measurements.
One other thing is to pay attention to the spread of the beam. It is usually printed on the side of the device, usually somewhere between 6:1 and 12:1 from the ones I normally see. This will mean that the beam is about 1" diameter for every 6 or 12 inches of standoff. So if you have an 8:1 unit and measure from 2 feet away, you are measuring an average from a 3 inch diameter, not just the little dot from the laser. The further you can stand off, though, I would guess the less the effect of the saturation I mentioned above. I haven't really played with this to be certain, though.
Hannable1975
Well-Known Member
My Raytech models at work say on the casing "not for clear fluids or polished metallic surfaces." Dunno if it is an accuracy thing, or a danger of reflection of the laser sight thing.
I use mine to take surface temp reading of my grains before using calculator to determine strike temp. Stir hands through grain to even out temp, hit grain directly with laser in a few spots, and you should have a good figure to enter into your strike temp calculator.
As for liquids/ongoing mash temps, I don't see a use for them.
As for liquids/ongoing mash temps, I don't see a use for them.
Something to keep in mind, depending on what you are using it for you can get a temperature gradient in your mash. It will only read the surface temperature which can be different than the temperature 6" into the mash bed.
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