According to a test by Cook’s Illustrated in 2011, different ovens set to the same temperature can vary by as much as 90 degrees.
Yes….90 degrees.
If you are an avid baker or cook (or even just an occasional one), this news should be a bit concerning. Or maybe this news is relief; you now have a valid excuse for why your sweet potato fries always burn! Or at least I do…
When we moved in, one of the first things I did was check the oven’s true temperature. It’s an older oven (edited to add: I don’t mean super old by the way. The oven in our last house was 30 yrs old and I doubt this one is more than 10 yrs, so technically, it’s newer to me) and I was concerned about switching to a new-to-me oven without checking things out first. It’s especially important to me because I post my recipes for all of you and I have to be as accurate as possible.
For some reason, I had a bad feeling about this oven, even though it’s quite nice on the eyes.
I set my oven to 350F and placed my oven thermometer (from Kitchen Stuff Plus) in the center of the oven on the middle rack. This would be the first of several tests I would end up doing.
[But it’s called a “TRUE TEMP”…what could possibly go wrong???]
The oven beeps when it has supposedly finished preheating, so I eagerly walked over to the oven when it alerted me. I didn’t want to impact the temperature by opening the door, so I quickly turned on the oven light and bent down to look at the temperature.
The oven temperature read about 290F or so. I can’t quite remember it exactly, but it wasn’t even close! I gave the oven the benefit of the doubt, assuming that it just took longer to preheat.
And I waited some more. The temperature climbed slowly and after a good 15 minutes, I decided it wasn’t moving anymore. I waited an extra 30 minutes just to be sure.
I squinted my eyes really hard (am I getting old or are those things just really tiny?)
To me, it looks about 315-320F:
This is about a 30-35 degree difference. I also tested various places in the oven (on the side and in the back), but they were all around that temperature give or take 5 degrees. I even left it in for a full hour just to be sure. Nada.
Every good researcher knows that it’s to never advisable to rely on a single study, right? So, I headed out and bought another brand of oven thermometer (this time from Canadian Tire) and tested it once again.
Replicate.
Wouldn’t you know it, the temperature was the exact same. Approximately 320 degrees Fahrenheit when it should have been 350. At least the thermometers are accurate. ;)
I Googled if there was any way to fix my wonky oven temperature and it turns out that it’s fairly easy to calibrate many kinds of ovens, depending on the severity.
Always start with the manual first. I looked for the owner’s manual, but wasn’t able to locate one (not surprising being in a rental and all). Eric suggested that we find the model number of our oven and see if we could find instructions online. He wasn’t able to find the manual online for this oven.
Eric finally ended up finding directions on Appliance 411- “How do I adjust the oven temperature on my range?”.
Following these directions, he was able to set the oven temperature higher (35F was as high as he could go), however it’s still not a perfect calibration. Now, when I set the oven to 350F, it heats to about 340F, so it’s still about 10 degrees too low. To attain 350F, I have to set the oven to 360F and also wait about 5-10 minutes after the oven tells me it’s preheated. This isn’t a huge deal, as long as I’m careful and I keep my oven thermometer in the oven when using.
The oven thermometer is probably the best solution we have right now, aside from actually paying someone to repair it (or asking the landlord), which I probably wouldn’t bother with unless it got worse.
Our first adventure in oven calibration is now complete.
One thing I love about this oven? The stove top heats up much faster than our old oven back at home. You win some, you lose some! I’ve burned a few veggie burgers so far, but I’ll get used to it eventually.
Have you ever measured your oven’s true temperature or calibrated your oven? I bet you sure are curious now…
Hmm… now I am wondering about my oven! I’m almost certain it’s off… but we live in a rental as well and will hopefully be moving soon so I won’t worry about this one. But, the next place, you can be sure I’ll be checking it out! xx
Hey Angela!
Love your blog! Your recipes inspire me to try and become vegan (umm… at least vegetarian one day)!
About your oven woes – Dorie Greenspan recently posted about it on her blog. Have you read this? http://doriegreenspan.com/2012/03/ive-always-had-an-inkling.html
I hadn’t seen her article but I just read it. Great read, thanks for sharing. I’ve heard similar things about oven temps going up and down. It’s a bit scary to think about how much ovens vary by brand and models.
I also love her reminder about why we give visual cues in recipes…very true.
I had actually read similar when I was trying to find a reason for why my baked goods NEVER came out right…surely it must be the oven’s fault, right?
Now I always let it pre-heat 20-30 min and have to turn it to just under 350 to actually get it there!
Good luck Angela.
it’s always the oven’s fault. Words to live by. ;)
huh. No, but I am currently house hunting and yup! Sounds like a project I will give my boyfriend once we find the right house!
Thanks, very useful info! In our old, dumpy apartment the oven was almost 100 degrees higher than what you set it at. But I invent my own recipes anyways, so I wasn’t even aware of this until we moved to our new house with a new oven. I started UNDERCOOKING everything. It’s kind of ironic because I was actually selling my baking out of my apartment to people I knew and never had any problems…I just figured healthier baked goods bake a lot faster. It was actually more challenging to adapt to our current oven that is the correct temperature.
You are a true researcher Angela! Making sure to perform multiple tests to assure the validity (or is reliability??) of the experiment.
…lol I’m a psycholog student too :p
Never thought of checking this before! Thanks for the tip! This could definitely explain why some people have trouble when making other peoples recipes…the wrong temp could definitely throw everything off!
Um, I better go calibrate the oven now… I hope I didn’t post a recipe with a false temperature!
D:
I know it messes with your mind, right? lol
Thank you so much, this is a great post… I never would have thought of this
That was really fascinating and useful! I have always wanted to test my oven temperature but was never sure how – now I feel comfortable! Thank you! Great post idea btw!
Glad you enjoyed it Fiona!
Wow that is helpful! I remember in my last apartment, the oven seemed to take twice as long to cook things.
Very interesting! I may have to find out what my oven isn’t telling me too!!
Wow, that’s crazy! I usually only use my oven on 3 temps – 350, 375 and 400 and my decision is made based on how hungry I am and how fast I want the food to be ready. Probably explains why I don’t do well when it comes to baking! :P
Ha! Thank you for this post. When we moved into our current house we inherited a beautiful stove with both a conventional and a convection oven. Lucky, right? Well, I found at first that my stuff wasn’t baking as expected even in the conventional oven… a pumpkin bread that I’d been making every year for YEARS was coming out like charcoal on the outside and not fully cooked on the inside. ARRRGH. Anyway, I figured out a bandaid solution – cook things at about 75 degrees less than called for, and for about 15 minutes less. Then they’d come out right. But now that I’ve read this, I’m thinking that maybe we can actually FIX the issue. That’d be fantastic! :)
WOW! I never thought about that! That’s kind of scary. You can bet I’m going to check my oven now! Thanks so much Angela!
A friend who often lives in rentals in foreign countries for months at a time considers her oven thermometer a kitchen must-have when she decides what to pack. She definitely has her priorities straight!
Sigh. Time to buy oven thermometer.
I did this when I become convinced that my oven runs hot. But… the thermometer said it’s spit on! I still think the back left corner is hotter though. I’ve started rotating pans half way through baking when possible to account for the hot spot.
yea I think hot patches in ovens are very common from what I read
OMG!!! If we can’t even trust our oven anymore… ;)
So diligent! I know this is something I should do, but I haven’t. Haven’t really had problems with the oven, but my stove top heats up very quickly, and we sometimes need to adjust. Anyway, thanks for the reminder!
Man, all I could think when reading this was “That oven is OLD?!” I suspect the oven in my house was the one here when it was built.
In the 1950s.
I’ve never tested the temperature, but I’m sure it’s outrageously off. I’m curious now, even though I don’t use it, really.
Old is relative, I guess. :) I didn’t mean super old. The one in our last house was 30 years old and I doubt this one is more than 10.
Love it! Very informative!