Hello,
Three different/distinct electronic thermometers read 205°-207°F in water at a full boil this morning. This was on the gas range and in an electric moka pot boiler. Since I just rehabbed the two LaPeppinas, I really don't wish to wipe out the washers quickly.
This is a new and disconcerting (to me) phenomenon. I do use soft water that has been run through a "Brita." Altitude 930'ASL.>30.19"Hg (1022.4 mb) at trial time. Not 3000Ft ASL.
What am I missing? Any theories?
richard

EDIT-There are some really good temperature measuring suggestions to follow. The answer I needed is: "The water must be at a full boil over a period of time for the total mass of the water to be at boiling temperature." That doesn't suit my use of LaPeppina and I found a way to work around the difficulty.EDIT.

The chances of your stove top defying the laws of physics are pretty low.

Where you are, water boils at 210. What's the plus/minus on those thermometers?

There's a chance that your brita filter is leaving things in the water that may affect the boiling point.

When was the last time you changed your filter?

http://www.dailycal.org/sharticle.php?id=4152

What readings do you get for distilled boiling water? Or better yet, a distilled water / ice slurry?

Thanks folks, I shall check all of the above. Brita=three months.

espressme wrote:Hello,
Three different/distinct electronic thermometers read 205°-207°F in water at a full boil this morning. This was on the gas range and in an electric moka pot boiler. Since I just rehabbed the two LaPeppinas, I really don't wish to wipe out the washers quickly.
This is a new and disconcerting (to me) phenomenon. I do use soft water that has been run through a "Brita." Altitude 930'ASL.>30.19"Hg (1022.4 mb) at trial time. Not 3000Ft ASL.
What am I missing? Any theories?
richard

What type of thermometer? Self contained, or reading off of a thermocouple?

If a TC, is the thermometer and TC matched types K-K? T-T? Mix them up and you can get a good difference.

Two are like this one and the other is a chef's pocket style. All are self contained. I don't have a separate PID type at this time.

Same temps recorded with distilled water at the boil. The sample time is about one second and the accuracy +-1°
I'm freezing some water at the moment.
richard
Plan "B" is to dis-assemble one and set it properly in ice water if the cold slush test proves out.
EDIT
in slush of distilled water all read 0°-32°-32.2°
Plan C. Use as is and offset in my mind ( assuming )
I may take one apart and throw ( solder ) on a TYPE "K" with the bolt end that I have and try again. Or I shall be stuck with the assembly of the NIB PID and parts I haven't yet gotten to.
Thanks to all that responded.
One of those days, I began it with pouring milk into my boiler and it went down hill from there! I do now have a real clean machine though! Three full times with the cleaning shtick yet!
Best brews to you all!
richard

espressme wrote:I may take one apart and throw ( solder ) on a TYPE "K" with the bolt end that I have and try again. Or I shall be stuck with the assembly of the NIB PID and parts I haven't yet gotten to.

I don't think soldering on the K-probe would have the desired effect. That picture doesn't look like a thermocouple thermometer. Probably a thermistor type instead?

Unfortunately, to be sure of getting good (1F) accuracy with a digital thermometer you will have to send somebody many dollars.

Most PID's need a small calibration offset, BTW. I have found that it doesn't matter too much whether you use distilled water for your ice point. It seems to be within 0.2F regardless. But for the boiling point, you must use distilled to get reliable results. My TC's measure BP within 0.2F of theoretical almost all the time now using distilled.

Jim

Richard -

As Jim said, the devices you have are all thermistor-based digital thermometers and, more than likely, are equipped with 100,00 ohm negative temperature coefficient (NTC) thermistors in their tips. These thermistors are NTC because as the temperature goes up, their resistance goes down, following a specific curve as described here:

http://www.ussensor.com/ussensor/index.html

Soldering in a thermocouple won't work - sorta like apples and oranges.

When you measure the temp in boiling water, it is usually best to lay a 1x2 across the top of the pot with some drilled holes to fit the diameter of the probes. Immerse the probe 1/4" to 3/8" below the water surface and let it stabilize for about a minute. The fact that they read 32.0 to 32.2 in the ice slurpy is a good sign but don't count on boiling temps being as accurate - I typically see ± 1.0 degree F, with 1.5 F being rare but possible.

possible the air bubbles are throwing things off?

erics wrote:Richard - Soldering in a thermocouple won't work - sorta like apples and oranges.
snip
When you measure the temp in boiling water, it is usually best to lay a 1x2 across the top of the pot with some drilled holes to fit the diameter of the probes. Immerse the probe 1/4" to 3/8" below the water surface and let it stabilize for about a minute. The fact that they read 32.0 to 32.2 in the ice slurpy is a good sign but don't count on boiling temps being as accurate - I typically see ± 1.0 degree F, with 1.5 F being rare but possible.

I do understand the reference. I am kinda sorta hoping there is a pot adjust in there somewhere. If not, I believe I can offset mentally to get within one degree of the target temps, 190°F-210°F. More than enough for my beginning skills. La Peppina is the one, and with care she does wonders.
Any one have some "mood ring" tape for the top of the group?.
Thanks all.
Richard