Stupid Question of the Day!

[RonRock]

OK sorry I have to ask, but here goes.

What temperature should a digital thermometer read in boiling water? 212* seems right but not sure if that is the temp the thermometer will show.

I ask because I just picked up a new one and it reads 210 in a pot of boiling water. I have several thermometers and they all read different. Hoping to have one I can trust.

 

[Darwin18]

The boiling point of water can differ slightly depending on what is dissolved in it as well as your elevation.

 

[XXguy]

Yep, 212 F is boiling at Sea Level. Higher elevations = lower boiling point. Pull a low enough vacuum, you can get water to boil at room temperature.

 

[bladefist]

Everything said here is correct, but also don't forget cheap digi therms are going to have an error of +- 1 or 2 degrees

 

[RonRock]

Thanks guys, I knew that. Just need a little hand hold now and then.

Now, anybody have a way to test a thermometer?

 

[jds]

The boiling point of water can differ slightly depending on what is dissolved in it as well as your elevation.

Yep. Up here in Denver, boiling is more like 202F, not 212. Brewers at altitude have to keep this in mind when doing infusions with boiling water or decoctions.

 

[the_bird]

Thanks guys, I knew that. Just need a little hand hold now and then.

Now, anybody have a way to test a thermometer?

Get yourself a lab thermometer (one of the old-school ones), which you should be able to count on as being accurate. If you've got a discrepancy, you at least know that ONE of the thermometers is bad (in all liklihood, the digital one).

 

[SpanishCastleAle]

Now, anybody have a way to test a thermometer?

What do you mean by 'test'? You can just put it in boiling water (and look for 212o F or whatever based on your elevation) and then fill an insulated cup with ice and just enough water to cover and measure that (obv looking for 32o F). Then, depending on the design, you can often turn that nut on the back to calibrate it.

I just did mine and it measured +2 on the low end and -4 on the high end...but I never use the low end of the scale so you can imagine how I set it.

 

[XXguy]

Google is your friend - I found this link for barometric pressure vs. boiling point.

Boiling Point of Water Calculator

The website makes the point that elevation calculations can vary depending on the currrent barometric pressure......so better consider the current weather before calculating a hard "fixed" temperature for boiling at your location.