What Your Oven Isn’t Telling You

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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.

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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.

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[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.

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I squinted my eyes really hard (am I getting old or are those things just really tiny?)

To me, it looks about 315-320F:

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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.

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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.

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Have you ever measured your oven’s true temperature or calibrated your oven? I bet you sure are curious now…

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{ 117 comments… read them below or add one }

Earthy Nicole April 5, 2012

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

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Madhuja April 5, 2012

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

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Angela (Oh She Glows) April 5, 2012

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.

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Kait April 5, 2012

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.

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Angela (Oh She Glows) April 6, 2012

it’s always the oven’s fault. Words to live by. ;)

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Misty April 5, 2012

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!

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Erica April 5, 2012

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.

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Carolina April 5, 2012

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

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kaila @ healthyhelper April 5, 2012

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!

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Jessica @ Chockohlawtay April 5, 2012

Um, I better go calibrate the oven now… I hope I didn’t post a recipe with a false temperature!

D:

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Angela (Oh She Glows) April 5, 2012

I know it messes with your mind, right? lol

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Jessica @ Chockohlawtay April 5, 2012

Thank you so much, this is a great post… I never would have thought of this

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Fiona April 5, 2012

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!

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Angela (Oh She Glows) April 5, 2012

Glad you enjoyed it Fiona!

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Shannon April 5, 2012

Wow that is helpful! I remember in my last apartment, the oven seemed to take twice as long to cook things.

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Brittany April 5, 2012

Very interesting! I may have to find out what my oven isn’t telling me too!!

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Angela @ Eat Spin Run Repeat April 5, 2012

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

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Christine (The Brighter Side of Life) April 5, 2012

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! :)

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The Mrs @ Success Along the Weigh April 5, 2012

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!

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Kale Crusaders April 5, 2012

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.

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Laura @ Sprint 2 the Table April 5, 2012

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.

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Angela (Oh She Glows) April 5, 2012

yea I think hot patches in ovens are very common from what I read

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Vicki April 5, 2012

OMG!!! If we can’t even trust our oven anymore… ;)

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Ileana April 5, 2012

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!

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Alex April 5, 2012

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.

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Angela (Oh She Glows) April 5, 2012

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.

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Adriane April 5, 2012

Love it! Very informative!

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Jesse (OutToLunchCreations) April 5, 2012

I have never measured my oven’s true temperature because its brand new…. but now I’m curious!

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Amber K April 5, 2012

I never even thought about this before. I had no idea they could be so far off!

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Kathryn April 5, 2012

I notice the new apartment oven seems much hotter. I’m also going from gas to electric. I miss my gas burners, but I like the electric oven. I’ve got to get myself a new thermometer (or 2) so see what is going on in there though!

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Averie @ Averie Cooks April 5, 2012

Wow this is SO informative. I need to test my oven like this. I’ve done tests to see where there are hot patches: lay white bread on a cookie sheet, like 8 slices and put it in at like 350F. My oven toasts the left half of the bread on the cookie sheet far more quickly and more intensity than on the right hand side. I could literally burn a pan of brownies on one side of the pan and keep them raw on the other, if I don’t rotate halfway thru. SUCH a pain….and this is a “nice” oven, that’s about 3 year old. Renting, don’t own, so I’m at the mercy.

I love this experiment you did and I will be doing my own now, too! Because if my 350F isn’t everyone else’s and vice versa, that is a huuuuuuge variable. Far more so than I’d say mis-measuring flour by 1/2 cup so to speak.

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Angela (Oh She Glows) April 5, 2012

That is another great test (about the bread slices) I will have to try that one out sometime.

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Destini April 5, 2012

I never even thought about this! I have actually gotten some emails from readers that have done a recipe of mine…and it was over cooked. I will be doing this asap!

Thanks for the great reminder!

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Stephanie @ Legally Blinde April 5, 2012

I’ve wondered about my oven temperature, but haven’t checked it myself. I have a gas stove so I’m not sure if I would be able to calibrate it, but I definitely want to get a thermometer so I can check it out! Thanks for the info!

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Joelle April 5, 2012

Yes, after way too long using it and wondering why it took SO long for things to cook in it! It’s about 10degrees too cool. It’s gas and I don’t have the manual so I just set it ten degrees warmer and wait a few more minutes after it tells me it’s come to temp. It seems to take a 3-5 more minutes to actually get there. It’s amazing what a difference just those 10degrees has made!

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Cath April 5, 2012

So funny! I did this recently. Ever since we moved into our rental, I knew that the oven was hotter than it says it was. I burned tray after tray of cookies, leaving the insides raw. I estimated that it was about 50 degrees hotter than indicated. Finally, after getting so frustrated when trying to bake, I went out an bought an oven thermometer. Turns out my oven is approximately 75-80 degrees hotter than it says!!! I was appalled, but relieved to know that it wasn’t my cooking skills. Wish I could say I went the extra step to try to fix the oven, but I’m lazy and just turn the oven to about 260 now when I need to bake.

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Angela (Oh She Glows) April 5, 2012

hah well that works too!

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Vegyogini April 5, 2012

My oven is only about 4 1/2 years old and I use an oven thermometer every time. The only frustration I have is that my oven thermometer seems incredibly slow and my oven beeps about 15 minutes before my thermometer measures the desired temp. That could either mean that the oven is beeping prematurely or that the thermometer is slow to register.

I had the gas company come out to calibrate the oven a couple years ago and he said it was right on, but really it runs about 5* cool.

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Angela (Oh She Glows) April 5, 2012

That’s a great point about the thermometer maybe being slow…it’s something we thought might be possible too!

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Jennifer April 5, 2012

Our first oven in this apartment was really, really old. It had a metal handle that got about as hot as the inside of the oven and a knob to set the temperature. Of course, all of the markings were rubbed off of the knob, so I had to get an oven thermometer and spend a LOT of time figuring out the oven temperature and where to mark the knob. Of course, the oven door didn’t have glass so I had do keep opening the oven door, thus giving poor readings. Our new oven is much nicer, but it didn’t take too many batches of dry muffins and burnt sweet potato fries to find that its fancy digital thermometer was a dirty dirty liar. I didn’t do quite as impressive or well-designed of a research project as you though – I just set the oven 15 degrees lower and it hasn’t failed me yet.

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Angela (Oh She Glows) April 5, 2012

lol @ dirty dirty liar.

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Carrie @shrinkingcarrie April 5, 2012

That is so funny that you posted this today! We just moved about a week ago and so I am getting use to a new oven at higher altitude. I made a new to me dairy/egg free french toast this morning and had my burner in between medium and low and it totally burned! I have to cook everything on low now! Blargh!
I better try your test out on my oven before I make your pizza recipe tonight!

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Angela (Oh She Glows) April 5, 2012

I’ve had vegan french toast burn on me too

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Meg April 5, 2012

Ah that is so annoying! I remember having serious oven troubles when we had an electric stove and convection oven. We recently switched over to a gas stove and convection over and luckily the newer version is working much better!

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Meredith @ DareYouTo April 5, 2012

I’m so impressed that you took the time and effort to do this (and made it look easy!). I’ve suspected for some time that my oven–very old, not even digital!–lies to me. It never crossed my mind to take a thermometer and verify, but now i’ll definitely be checking into the situation…

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Cait's Plate April 5, 2012

Oooh interesting. I never knew that was the case!

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Ashley April 5, 2012

Lol I LOVE that you replicated your experiment by going out to buy another thermometer. I’ve never checked my oven before but I know I should. I think mine gets too hot.

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anne April 5, 2012

Great experiment! I need to test my oven now.

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Grace @ Healthy Dreaming April 5, 2012

You did the test so scientifically even with TWO thermometers! Now I’m wondering how my oven reads..

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Lena April 5, 2012

My oven actually IS super-old. The oven thermometer is my only way of knowing what temperature I have set it to. The dial doesn’t even have marks! It may have at some point, but as far as we can tell, the kitchen was built in the 1920s, and the oven came in maybe as late as the 1950s, probably earlier. So any marks that may have once existed have been rubbed into oblivion. It’s adorable, but it took some getting used to.

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Angela (Oh She Glows) April 5, 2012

I bet it did! It must have a ton of character though..would be cool to look at if anything.

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Erika April 5, 2012

After moving into our rental from a house with a brand new oven to a house that is far more dated, I bought an oven thermometer to see what the temperature was reading since this oven has a dial and is hard to tell what you are really setting it at. Ends up I have to wait an extra 10 minutes after it says the oven is preheated to get the correct temp…no big deal, just helpful to know :) Smart to do from time to time. I actually keep my thermometer in the oven and always place it at the same level of whatever it is I’m baking to ensure that it is at the right temp….

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Angela (Oh She Glows) April 5, 2012

yea that’s exactly what I’ve been doing too. Peace of mind :)

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Nicole April 5, 2012

Wow – that is some serious kitchen commitment! I’d never thought to test the oven!
I do feel like my b-f’s gas oven is much better for baking than my electric oven. I love cooking with gas!

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