The case of the illiterate thermometer...

[sboyajian]

About 4 weeks ago I brewed three 1 gallon test batches of three different beers.

Saison, IPA and Oatmeal Stout. The Oatmeal Stout was my attempt at converting my PM recipe to AG.

I did hit my gravities on the Saison and the Oatmeal Stout, however attempted to hit the 1.080 of the IPA twice and both times landed at 1.056. I was baffled. I hit my temps, took my time, everything seemed right (didn't have any iodine to test). The Stout came out super thin and boozy and finished 12 points lower than expected. The IPA Finished 6 points lower than expected. The saving grace is the Saison finished at 1.002 (I'm ok with this).

Last night I used my thermometer for something and it just seemed... wrong. It was at this moment that I realized my thermometer was illiterate!

Took a measuring cup and filled it with tap water. Put my thermometer in and it read 80°F. Put my wifes cheese thermometer in and it read 73°F. Put an old school mercury thermometer in and it was at 72°F. Digital meat thermometer, 72.6°F.

Now knowing that at such a low temp I was nearly 8° off, I can't imagine how much it could be off while I'm trying to get 168°. Quite possibly when I thought I was mashing at 154, I was really at 144-146.

Moral of the story: Check your equipment on a regular basis.

 

[ImNoExpert]

Ouch! Can I ask what brand so that I may stay away from it?

 

[edroberts]

I have had the same type of horrible luck with thermometers. Even a traditional alcohol thermometer I had was reading 7-8 degrees too high. I had gotten to the point of using 3 different thermometers to get and "idea" where temps were (alcohol thermo, meat thermo, turkey fryer thermo).

I finally grabbed one of the Thermoworks thermometers (not thermopen) that be calibrated. Not as quick reading as a Thermopen, but is supposed to have the same stability through all temperature ranges as one.

 

[Onkel_Udo]

I have had the same type of horrible luck with thermometers. Even a traditional alcohol thermometer I had was reading 7-8 degrees too high. I had gotten to the point of using 3 different thermometers to get and "idea" where temps were (alcohol thermo, meat thermo, turkey fryer thermo).

I finally grabbed one of the Thermoworks thermometers (not thermopen) that be calibrated. Not as quick reading as a Thermopen, but is supposed to have the same stability through all temperature ranges as one.

Most Dial thermometers can, and should be, calibrated just by turning the nut on the back.

The most accurate way to do this unless you have a lab calibrated alcohol thermometer that you trust is to test it in boiling water (record the reading) and the in a cup of half-melted ice (record the reading) assuming the scale covers freezing to boiling. If both reading are "off" you have to interpolate and pick what you want for accuracy. For a mash thermometer , the higher end of the scale is more critical so err to getting the boil temp close at the expense of the 100 f and under.

 

[1977Brewer]

I found out on my last batch that the meat thermometer I was using for my first reads about 10 degrees high. Explains how that batch got to 1.006. It's a SMaSh IPA, so it can be dry, I just wish it was a little less so. So, yes, triple check your thermometer.

 

[GilaMinumBeer]

Show it the website by Austin Kerr. That'll teach it temperance.

 

[sboyajian]

Ouch! Can I ask what brand so that I may stay away from it?

No idea... but......

Most Dial thermometers can, and should be, calibrated just by turning the nut on the back.

This Guy!!! This guy is like some kind of morphed together version of Mr. Wizard and MacGyver. Checked the back of my thermo, found the nut, gave it the ol' reach around. Tested at hot and cold and it's in line with the others now.

Good looking out!

 

[Onkel_Udo]

This Guy!!! This guy is like some kind of morphed together version of Mr. Wizard and MacGyver. Checked the back of my thermo, found the nut, gave it the ol' reach around. Tested at hot and cold and it's in line with the others now.

Good looking out!

Nope...11 years in the restaurant biz.

Glad I could help.

 

[sboyajian]

Well, my wallet, my future mashes and my taste buds thank you.