Stick on Thermometers

[nicklawmusic]

How accurate are stick on thermometers? I seem to get two readings simultaneously!

For example, my wort is currently showing 20c but 22c and 18c are both showing slightly too.

 

[Jim_Holmes]

some of them ive had dont work at all and others were spot on best way to tell how yours are is to put some water in the fermenter your using the thermometer on and wait a couple hours to see what its reading then use a digital thermometer and see what you get with it. that way you can see the difference then just mark the fermenter with plus or minus however many degrees difference

 

[bajaedition]

When I used Glass carboys I had one on each carboy, they all seem to read the same.

 

[Hello]

Mine seem to reflect the temp within a couple degrees. I've checked the liquid crystal strips and then took the temp of the sample to check. Sometimes the ones that are written vertically read as you're saying.

 

[raouliii]

How accurate are stick on thermometers?....

Not very. They seem to be influenced by the ambient exterior temperature, especially if there is a large differential.

 

[doornumber3]

Not very. They seem to be influenced by the ambient exterior temperature, especially if there is a large differential.

Do a test with them. They are a whole lot more accurate than you think. I find within .5 degrees.

 

[Grannyknot]

I've always felt they were accurate enough to gauge safe pitching temps & generally accepted ale fermentation ranges.
But if you're looking to ferment at a specific temperature, best to go with a chamber & controller.

 

[NTXBrauer]

I would keep in mind the +/- 2 degrees mentioned above. The only exact way to measure the wort temp is drop a thermometer in it. Of course this could introduce exposure of contaminants to the wort, so the majority of us rely on the stick ons.

The only way I can see to calibrate a stick on thermometer, for your brewing environment, is to fill an empty FV with water. Let it set until you have a reading on the stick on, then drop a thermometer in the water to determine the delta (if any). This will be as close as you can get, taking into account all the stick ons you use are exactly the same.

 

[Grannyknot]

A friend of mine recently bought one of the glass wide mouth fermenters from NB.
He stuck one of these on the inside of it:

Its in a brown ale, and is close enough to the glass that he can read the temperature.
Said its been in there a week and a half, so it survived the worst of the violent fermentation without coming un-stuck.

Seemed like a good idea.

 

[RM-MN]

How accurate are stick on thermometers? I seem to get two readings simultaneously!

For example, my wort is currently showing 20c but 22c and 18c are both showing slightly too.

Why do you care? Ales ferment at a wide range of temperatures and while we will tell you to ferment them cool, a couple degrees won't make much difference in the finished beer.

 

[Hello]

Why do you care? Ales ferment at a wide range of temperatures and while we will tell you to ferment them cool, a couple degrees won't make much difference in the finished beer.

Why wouldn't he care about knowing if his ale is fermenting at a less than desirable temperature?

 

[texcan2000]

They are accurate. Go with the middle number.

 

[Clonefan94]

I've always felt they were accurate enough to gauge safe pitching temps & generally accepted ale fermentation ranges.
But if you're looking to ferment at a specific temperature, best to go with a chamber & controller.

This seems to be my experience as well. Heck, the gradations on mine are in 2 degree increments anyways, so it can only be so accurate anyways. I usually brew basic ales, so as long as it's reading in the mid 60s, I know I'm good to go. That's all I'm really concerned about anyways.

 

[RM-MN]

Why wouldn't he care about knowing if his ale is fermenting at a less than desirable temperature?

He should care but a couple degrees won't make much difference unless he's fermenting right at the edge.

 

[nicklawmusic]

I do care about the temperature. It makes the difference between a good and bad beer.

 

[petrolSpice]

The one's I've used are surprisingly accurate. The number that is solid green is the temperature. The number below will be blueish and the number above will be brownish. This is for the Fermometer. I know there are some other ones out there that might work differently.

They are also heavily influenced by ambient temp. So as long as the fermenter temp is relatively close to ambient then it should read fairly accurately.

 

[coolharry]

If there's two numbers "lit up" its between those, if there's three numbers "lit up" go with the middle. Mine usually always have multiple cells with a bit of color.