Oven Calibration

[mattl]

I bought my oven a few years ago, an expensive Electrolux, and while it does an OK job I question the accuracy of the thermometer.  When I fist got it I used a candy thermometer to adjust it, I do have a Taylor Technician thermometer but some how the mercury got divided and I never know what it reads.  The oven always seems a bit slow to me, or at least what I'm used to.  Typically a pumpkin pie that says bake for 50 minutes takes more like 70 minutes.

 

Anyway picked up a VOM the other day that included a temp probe.  At room temp it was correct and as a rudimentary test instrument I'd expect it to be relatively accurate.  So I set my oven at 350 and watched.  initially the temp shot up to 385, the oven turned off, and allowed the temp to drop to 338.  Subsequently the temp swing reduced to 358 up to 386, after half an hour I see the oven heat up when the temp reaches 356.  That's a 30 degree swing which is normal from what I read, I just wonder is I should adjust it down so it swings around the 350 degree mark or leave it a bit hot.

 

Next I'll have to test my old Frigidaire CI and see how a mechanical thermostat responds.

 

BTW, here is an interesting read on the subject.

A Brief History of Oven Temperature—and Why It’s Not as Exact as You Think

“Preheat oven to 350 degrees.” I hate this phrase. First, as George Carlin pointed out, it’s linguistically absurd—you don’t preheat an oven, you heat...

www.slate.com

 

[davey7]

It's my understanding that's how modern ovens work. Vintage ovens like my O&M hold the oven temp pretty well.

The gas in modern ovens cycles on and off while (gas and electric I think), in mine for example, the flame modulates up and down to hold the temperature fairly even.

 

[kb0nes]

Matt, what is the sensor you meter uses, is it a simple thermocouple junction of something with more mass?

The reason I ask is that I have found my bare thermocouple gets affected by the infrared radiation from the broiler causing it to read high. I created a shield by rolling a ~1" dia tube of aluminum foil that I placed the thermocouple inside of. The wide swings in temperature were increased by direct heating of the sensor from the radiation. With the shield in place I saw less variation likely more indicative of the true air temperature.

At the end of the day I'm not sure it really matters too much that you achieve absolute accuracy in the setting. Its more important that it is consistent and that you are familiar with your oven. Interesting that in your case you are seemingly reading higher then expected temperatures but feel the oven is slow.

 

[rinso]

Gas or electric oven? I do know that my gas GE profile has wide temperature swings.

 

[mattl]

Electric.

 

In doing some further reading I came across this on another forum:

 

<blockquote>
I think you are over analyzing this. Here is how you check the temp of oven with a thermocouple probe type thermometer.
Preheat oven to 350 let it cycle 2 times
take temp reading at its high point then take temp reading a low point, do this twice.
average out the results: example oven cycles at high point of 360 low point 345 first reading
second reading 362 high 348 low add them all together for a total of 1415 degress divide by 4 = 353.75 degress. That would be dead on balls accurate. You should be able to recalibrate your electronic control + - 25 degrees. If its over 25 degrees off set temp then ohm out sensor with the measurements I posted before.

</blockquote>

 

[maytagbear]

My Whirlpool

gas oven has a narrow temperature swing, thanks to their "Accu-Bake" system. I get perfect baking from it.

An easy and accurate test was told to me by an oven tech years ago, and it is still valid: Get a Pillsbury (or similar) refrigerated dough product ("Grands" biscuits or a cinnamon roll variety), heat the oven to the temperature on the label, wait 30 minutes after the oven beeps (if new or newer), bake the product for the time on the label. Check at the minimum time, and if the item is burned, thermostat is too high, and if not done after the maximum time, thermostat is too low. If you choose to, you can eat the test material!

Good luck.

Lawrence/Maytagbear

 

[brisnat81]

Also from a time to cook perspective, look at how well the oven seals.

Since I got our new Westinghouse wall oven, I've had terrible trouble trying to get stuff to brown. It has a European A energy rating, which means its sealed that tightly, that none of the moisture can get out unless you open the oven door.

Stuff quite often cooks, but getting it to brown is a challenge and a half.

It maintains the set temp perfectly however.

 

[rockland1]

Oven Operation

From my experience I would say it's operating as it should. As a long time baker, I would always prefer my oven to be on the hot side.