thermometer accuracy

[thaefathan]

Hi, with my last brew I used 2 floating thermometers and a new long stem thermometer from the LHBS. During the mash the 3 of them gave me 3 different readings with a 20F spread, so I have no idea which one is correct.

Today I brewed, and I used an IR thermometer from amazon (Etekcity Lasergrip 774). During the mash the stem thermometer read 152F, and the IR read 140. During the boil, the stem thermometer is maxed out above 220F, and the IR reads 197ish.

I'm looking to hit the right temps of course and I was assuming the IR thermometer would be the most accurate across a large temp spread, since it's not dependent on a piece of metal bending.

Has anyone else had the same problems? Solutions? Any advice? thank you

 

[Gavin C]

Get a Thermapen.

Sign up for their emails and sales info and wait for a clearance of open box or unwanted colors

$79 +tax and shipping.

Great thermometer. Excellent temperature control of the mash and other things will benefit your beer in all likelihood.

I got mine during a Paddy's Day sale on green ones.

I've seen browns and purples on sale for $79 also before I unsubscribed from the emails. Regular price is $99

Edit: That stem and IR both sound like garbage. Too far off. Boil is 212 or extremely close (-1F) to it unless you're brewing at altitude.

 

[SanPancho]

only way i've ever been taught to calibrate /check thermometers is to pack a cup with as much ice as you can, top off with cold water and wait a minute for temp to equalize. the thermometer closest to 32F is your winner.


how that translates to temps up at 100, 150, 200F, etc i have no idea.

 

[flars]

The TheroWorks site has good instructions on testing the accuracy of thermometers at the freezing point.
http://www.thermoworks.com/learning/thermapen101_creating_an_icebath.html
Your thermometer will read 1°F under 212°F, in boiling water, for each 500 feet above sea level when checking the thermometer for boiling point accuracy.

Site also has good information on the limitations of IR thermometry.
http://www.thermoworks.com/learning/

I had several dial thermometers that were so far off they were tossed, even with using the calibration screw one had.

 

[flars]

ThermoWorks has an open box sale going. The Dot has a long probe for liquid environments.
http://www.thermoworks.com/specials...x&utm_campaign=July2015-Primitive-Grilling-cs

 

[doug293cz]

Hi, with my last brew I used 2 floating thermometers and a new long stem thermometer from the LHBS. During the mash the 3 of them gave me 3 different readings with a 20F spread, so I have no idea which one is correct.

Today I brewed, and I used an IR thermometer from amazon (Etekcity Lasergrip 774). During the mash the stem thermometer read 152F, and the IR read 140. During the boil, the stem thermometer is maxed out above 220F, and the IR reads 197ish.

I'm looking to hit the right temps of course and I was assuming the IR thermometer would be the most accurate across a large temp spread, since it's not dependent on a piece of metal bending.

Has anyone else had the same problems? Solutions? Any advice? thank you

IR thermometers don't work well on boiling liquids. The steam cloud blocks their view of the surface, so you don't really know what they are reading.

Brew on

 

[Gavin C]

The dial thermometer on my pot is only useful for relaying a stable temperature.

Thermoworks goes into great detail about calibration.

With my Thermapen I have been able to tackle multi step mashes with my direct fired mash-tun (BIAB). Each step hit on the nose to within 0.5F

Not feasible with a slower reading thermometer I had before. The control just wasn't there.

One of the best purchases I have made for brewing. Great for cooking too.

I probably use it too much. Love my Thermapen

Verifying Mash out step at 168F

Hydrometer sample at correct calibration temperature.

 

[thaefathan]

Well thanks for all the replies. I ended up ordering :http://www.amazon.com/gp/product/B0021AEAG2/?tag=skimlinks_replacement-20

They claim it has a +/- 2F accuracy, which is good enough for me.

 

[Stealthcruiser]

IR thermometers don't work well on boiling liquids. The steam cloud blocks their view of the surface, so you don't really know what they are reading.

Brew on

What he said, and they don't work well on most shiny surfaces, ( re: standing water).

 

[normonster]

Bah. Calibrate with spirits based thermometer and you're set.