# How do Microwaves know how long to cook Potatoes? **URL:** \ **Category:** Cafe Society\ **Created:** [July 13, 2015, 3:02am UTC](https://boards.straightdope.com/t/how-do-microwaves-know-how-long-to-cook-potatoes/725006 "2015-07-13T03:02:09Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [July 13, 2015, 3:02am UTC](https://boards.straightdope.com/t/how-do-microwaves-know-how-long-to-cook-potatoes/725006/1 "2015-07-13T03:02:09Z")
Inspired by the other _how to bake one_ thread, I always cook mine in a microwave. They come out almost identical to a regular oven, and 5 minutes versus an hour and a half is a tad bit of a deal-breaker! Microwaves now usually have a ‘Potato’ button on them. I’ve never actually checked if the time changes, but when you press it the display just shows **POTATO** for a few minutes before eventually changing to a countdown of like 1:30. I’ve used it for potatoes of somewhat varying sizes and it always seems to work perfectly on each. It seems to do the exact same thing with microwave popcorn, but I had assumed that when you use the POPCORN button microwaves sensed the sound of the popping and when it starts to stop it switches to a countdown of 20 or 30 seconds. Does the POTATO setting sense anything? And if not why doesn’t the display merely show the countdown time after you push it? Is it just faking you into believing it’s a ‘smart’ setting? ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [July 13, 2015, 3:23am UTC](https://boards.straightdope.com/t/how-do-microwaves-know-how-long-to-cook-potatoes/725006/2 "2015-07-13T03:23:42Z")
5 minutes? Mine jumps to 10. 10 minutes is just right for two potatoes in a 2-cup Pyrex measuring cup. Maybe part of the secret is that potatoes are okay if you overcook 'em some. ---
**Author:** ![BundleOfStix](https://avatars.discourse-cdn.com/v4/letter/b/ed8c4c/32.png) [@BundleOfStix](https://boards.straightdope.com/u/BundleOfStix)\ **Post date:** [July 13, 2015, 3:59am UTC](https://boards.straightdope.com/t/how-do-microwaves-know-how-long-to-cook-potatoes/725006/3 "2015-07-13T03:59:28Z")
I cook mine in a cloth “tater baker” for 2:22, because I can’t be bothered to enter in a round number . They come out great for frying that way (sliced or shredded into hash browns), but they’d need a couple more minutes to eat as “baked”. I loves me some taters! ---
**Author:** ![Missy2U](https://avatars.discourse-cdn.com/v4/letter/m/3bc359/32.png) [@Missy2U](https://boards.straightdope.com/u/Missy2U)\ **Post date:** [July 13, 2015, 4:30am UTC](https://boards.straightdope.com/t/how-do-microwaves-know-how-long-to-cook-potatoes/725006/4 "2015-07-13T04:30:29Z")
I must have a really cheap microwave because I always figured the preset conveniences were there because the manufacturer already knows how long a potato or popcorn (or other very frequently microwaved foods) will on average take to cook in that model, thereby saving my lazy consumer ass from having to punch a few more buttons. I guess mine doesn’t come with special sensing type microwaves. 😉 And the reason mine doesn’t count down is because it isn’t how they made it. ---
**Author:** ![Shoeless](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/shoeless/32/7099_2.png) [@Shoeless](https://boards.straightdope.com/u/Shoeless)\ **Post date:** [July 13, 2015, 1:35pm UTC](https://boards.straightdope.com/t/how-do-microwaves-know-how-long-to-cook-potatoes/725006/5 "2015-07-13T13:35:27Z")
I can’t answer for all microwaves but ours senses the amount of steam in the oven and uses that to determine when a potato, or popcorn, or reheated plate of leftovers is done. And yes it does adjust the time as it is cooking. ---
**Author:** ![Missy2U](https://avatars.discourse-cdn.com/v4/letter/m/3bc359/32.png) [@Missy2U](https://boards.straightdope.com/u/Missy2U)\ **Post date:** [July 13, 2015, 2:18pm UTC](https://boards.straightdope.com/t/how-do-microwaves-know-how-long-to-cook-potatoes/725006/6 "2015-07-13T14:18:08Z")
> [@Shoeless](#): > > I can’t answer for all microwaves but ours senses the amount of steam in the oven and uses that to determine when a potato, or popcorn, or reheated plate of leftovers is done. And yes it does adjust the time as it is cooking. So I checked with my husband who knows of such things. He confirmed a couple of things - he said that yes, what you said sounds absolutely correct, and that yes, we have a really cheap ass microwave. 😃 I never knew that - thanks! 🙂