Food Safety

Will a Baked Potato Really Explode If You Don't Prick It?

To prick, or not to prick?

September 27, 2018
Explosions just waiting to happen? Photo by Rocky Luten

A few weeks back, we came across a hotline question that rocked our worlds:

“I am wondering: Is it really necessary to prick potatoes and sweet potatoes before baking them? In what context? Or is this just a cooking myth from days of yore?”

Our team Slack channel lit up like a Christmas tree. Between two recipe developers and three food editors with more than 100 years of collective cooking experience/obsession, we had zero hard answers—and zero incidents of potato explosion among us. So we turned to science.


A Half-Baked Experiment

Finding potatoes of roughly equal sizes was more than half the battle. Photo by Ella Quittner

Initially, we thought that an experiment could provide the answer. We scoured the produce bins for two white potatoes and two sweet potatoes of equal sizes. Into the oven they went, at 425° F, one of each variety pricked all around with the tines of a fork about an inch and a half deep. The sweet potatoes took about 45 minutes to fully cook through, while the Russets (aka Idaho potatoes) took a little over an hour.

Photo by Ella Quittner

The results of this "experiment" were largely underwhelming—no explosions occurred, and all four potatoes had a very similar internal texture. (The only real difference was the darkening of the flesh of the Russet I'd pricked, due to an oxidizing reaction that occurred when I let it sit out for a half hour before baking.) If anything, the pricked Russet potato had a slightly less soft center, which I think would've been mitigated by another five minutes in the oven.

With a sample size of four, we're not surprised that we didn't get conclusive information. But greater experiments, like the one Cook's Illustrated ran in its journey to the perfect baked potato, have yielded equally blurry answers:

Everyone knows that you have to prick potatoes before baking them so steam doesn’t build up inside and cause them to explode. Well, we baked 40 potatoes without doing this, and not one exploded. But since it takes so little effort, here’s one time we’ll err on the side of caution. It could be the 41st one that explodes.
Cook's Illustrated

Unsatisfied with the results of our great potato bake-off, we called in the big guns, straight from potato country.


Expert Advice

"Yes, it’s good to prick them," says Brennan Smith, a faculty member of the School of Food Science at University of Idaho. "It pokes holes in the skin, which allows steam to escape. Otherwise, they could explode—it doesn’t happen all the time, but it happens every once in a while. The potato is full of water it’s trying to turn to steam, or water vapor. The skin acts like a pressure vessel. If you don’t let the steam escape, it builds up pressure—if it gets to a certain point of pressure from the water trying to become water vapor, it can pop the skin."

According to Smith, this is more likely to happen in a microwave than in an oven, because the rate of heating is faster, and there's less time for the pressure to escape naturally.

There's no material difference, he says, when it comes to the type of potato—sweet, or one of the white- or yellow-fleshed varieties. Both should get pricked.

And the tiny ones, like fingerlings or new potatoes?

"They have more surface area—more than likely, they’ll be less prone to explode," Smith tells me.

So, will a baked potato explode if you don't prick it? The answer's a firm "maybe." Or more accurately, "sometimes." If you don't want to risk it, just prick it.


Got potatoes on the brain?

Which kitchen theories would you like to see debunked? Let us know in the comments!

24 Comments

Marit G. October 19, 2018
I think most potatoes don't explode because we pierce the skin while scrubbing them! Thicker skinned ones do explode. I once had the inside of the oven covered in mashed potatoes as I forgot to prick them, 6 spuds said bang, bang etc. awful cleaning up job
 
kitchenyoda October 10, 2018
YES! Potatoes can explode in the oven. Even WHEN you prick them. I have been baking potatoes in the oven for over forty years. I always give them a quick couple of pricks with a fork before putting them into a 450 degree oven. Last year, for the first time, I had a potato bomb go off in my oven -- potato confetti everywhere. All of the other potatoes in that batch were fine. Now, I make sure I prick them a little more deeply, and on all sides, before putting into the oven. Take the precaution! Cleaning baked potato confetti out of the oven was not fun.
 
Stephanie W. September 30, 2018
We heard a loud pop in the kitchen but I didn't figure out what it was until I checked the potatoes, later. Mashed, burning potatoes all over the oven!
 
A.S. September 28, 2018
Yes, I had a russet explode potato fluff all over my toaster oven a couple months ago. I had even pricked it but just not enough I guess.
 
Author Comment
Ella Q. September 28, 2018
A cautionary tale! I'll be pricking from here on out.
 
Kay T. September 28, 2018
Exploding potatoes...yikes. I've baked sweet, and russet potatoes for 60 years in the oven..mainly because the microwaved potatoes loose their appeal and taste to me. I do pierce potatoes that go in the microwave. When cooked in oven, no piercing, I butter the skins, wrap in foil, and cook at 500degrees for at least an hour. Maybe I've just been extremely fortunate, but none of them had a cracked skin or a blowout! Thank goodness!!!
 
Author Comment
Ella Q. September 28, 2018
I feel so lucky, too! I’ll be pricking from now on...
 
Carol S. September 28, 2018
Just a week or two ago, roasted a pan of little new potatoes from my garden. I forgot to prick them, and 2-3 burst! There were bits of potato all over the oven. :(
 
Author Comment
Ella Q. September 28, 2018
Good to know! I never prick tiny potatoes, but will now (when I don’t halve them).
 
Lisa S. September 27, 2018
I had a russet explode when it hit the cold plate from the hot oven. The result was second degree burns to my thighs. Yes they will explode on occasion! Better to be safe than sorry.
 
Author Comment
Ella Q. September 28, 2018
I’m so sorry, Lisa! Agree, better safe than sorry.
 
Mary C. September 27, 2018
Yep i had one explode all over the oven.
 
Rosemary September 27, 2018
The last time I put small potatoes into the microwave without pricking was, indeed, the last time I'll do that. At least, purple potato flesh is easy to track down in the white oven interior. I have also seen (fortunately not my oven) russets explode in the oven.
 
Liam F. September 27, 2018
Conduct this experiment again using a microwave instead of an oven. They will explode!
 
Frodis September 27, 2018
Yeah, I've seen it once over the years. Left shredded potato over the inside of the oven. There has got to be a better way to make hash browns!
 
Author Comment
Ella Q. September 28, 2018
Ha! Agreed.
 
Paul D. September 27, 2018
Busy steakhouses cook several thousand baked potatoes and sweet potatoes every week, and pricking isn’t in the procedure. In 20 years in the business though, I’ve seen hundreds pop on their own or with just a slight bump upon removal from the oven. A pricked skin may be a safer route, but I doubt it would allow for the ultra-fluffy texture we all want from our spud!
 
Smaug September 27, 2018
I find it hard to believe that anyone has baked any significant number of potatoes (or sweet potatoes) without exploding one. It's usually not spectacular- just a little pop opening a crack in the skin and some of the flesh oozing out, but not what you want.
 
Paul W. September 27, 2018
I never heard of exploding potato's until it happend to me. I heard a loud thump in the kitchen, did'nt think much of it till i opened the oven, the site was horrific and it took over an hour to clean up the carnage.
 
Eric K. September 27, 2018
Scary! And good to know...
 
Kathy G. September 27, 2018
I forgot to prick a potato one time and it exploded all over the oven. Will always poke it with a fork a few times from now on.<br />
 
Author Comment
Ella Q. September 27, 2018
Same here, I'm not going to risk it!
 
DCT September 27, 2018
I have baked many a potato in my life without incident, but I will not forget the time one exploded in my oven. It happened when I poked it to check on its doneness. In an instant there was potato all over my oven. I was lucky it didn't hit me. So, better be safe than sorry; I now stab them several times. With vigor.
 
Author Comment
Ella Q. September 27, 2018
That sounds alarming, to say the least! A good lesson for all of us :)