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Microwave Timing Conversion Charts
October 17, 2013 8:20 PM   Subscribe

So the label on your frozen food gives a cook time, but it says it's for a microwave of a wattage other than what it says on yours. How are you supposed to know how long to nuke it for? Well, you could consult one of these handy charts!
posted by Pope Guilty (64 comments total) 43 users marked this as a favorite

 
more from Marie T. Smith, author of Microwave Cooking for One

-Reheating for Dummies
-Totino's® Presents: Pizza Roll Pastas!
-Hey, Put a Pop-Tart on an Otherwise Empty Plate
-God Has Deserted His Children
posted by theodolite at 8:27 PM on October 17, 2013 [29 favorites]


You're still going to burn that popcorn and stink up the entire building.






ಠ_ಠ
posted by louche mustachio at 8:32 PM on October 17, 2013 [6 favorites]


Yeah, it's a very silly book, but I thought the charts were pretty nifty and useful.
posted by Pope Guilty at 8:32 PM on October 17, 2013 [1 favorite]


Shouldn't this be an AskMe?
posted by monospace at 8:33 PM on October 17, 2013 [1 favorite]


I microwave everything but popcorn for three minutes.

With my trusty microwave? It works ever so well.
posted by Samizdata at 8:34 PM on October 17, 2013 [1 favorite]


you could consult one of these handy charts!

I am in your debt, good sir!

If anyone else would like me in their debt, please let me know what my microwave's wattage is!
posted by Alvy Ampersand at 8:36 PM on October 17, 2013 [6 favorites]


OK, she's assuming that the cooking time should be inversely proportional to microwave power, but have the Mythbusters tested this? I think not!
posted by lukemeister at 8:37 PM on October 17, 2013 [1 favorite]


Alvy Ampersand: The NSA said 1275 +- 3 Watts as of last week.
posted by lukemeister at 8:39 PM on October 17, 2013 [8 favorites]


If it's only proportional to power, what's the point? I doubt this is the case either.
posted by wotsac at 8:42 PM on October 17, 2013


People plan it out? My microwave may as well have two buttons: add a minute and popcorn.
posted by 2bucksplus at 8:42 PM on October 17, 2013 [8 favorites]


For me, everything gets five minutes, but I will pull the door open at any stage I feel I want to look at the thing I am microwaving. Then I decide if it gets another unit of five minutes (usually after a nice stir). Remember, I can pull the door open at any stage. This releases healthsome radioflavinoids into my hair and skin, which would otherwise have evaporated as they are drawn out of the food by the microwaving process.
posted by turbid dahlia at 8:55 PM on October 17, 2013 [6 favorites]


Who are the people who know the wattage their microwaves?
posted by dogwalker at 8:57 PM on October 17, 2013 [4 favorites]


Who are the people who know the wattage their microwaves?

It's been printed on the front or just inside of the door of every microwave I've ever owned.
posted by Pope Guilty at 9:00 PM on October 17, 2013 [8 favorites]


Jeez. Just use arithmetic, it's mostly proportional to power.

Now, for particularly small or sensitive items, it can be possible to overcook the outside parts easily or cook it unevenly, so you might really want to turn that 1400 watt monster you've got down to 50% power for some items.

And, from firsthand experience, I will say that the linearity of the power regulation in the Panasonic Inverter microwave ovens is really nice. (The normal microwave ovens just turn the power on and off on a rather macroscopic timescale, which is why it sucks.)
posted by mmagin at 9:07 PM on October 17, 2013 [3 favorites]


Oh, inside the door, that's real useful. That's like not knowing how much petrol is in your car until you've started the engine.
posted by turbid dahlia at 9:07 PM on October 17, 2013 [4 favorites]


Actual useful information: the "power" settings on your microwave are very useful, especially with frozen items. Microwave ovens work by exciting liquid water molecules in food. Since frozen items contain relatively little liquid water, it's much harder for the waves to penetrate, so you end up heating only the outside.

Lowering the power does not actually reduce the wattage, but instead momentarily pauses the heating waves, giving a chance for the heated outer areas to defrost the adjacent inner areas due to proximity. Then when the waves kick back in, they can effectively heat further into the food. The process repeats, and eventually all of the food will be more evenly heated.
posted by ShutterBun at 9:21 PM on October 17, 2013 [10 favorites]


Five minutes on high for a lump of frozen mince is basically the protein-rich equivalent of fried ice cream, which is delicious.
posted by turbid dahlia at 9:29 PM on October 17, 2013


This may be the least controversial Mefi post of all time.

NUMBER TABLES.
posted by GuyZero at 9:32 PM on October 17, 2013 [4 favorites]


Mine is mostly popcorn, reheat coffee and how to tell if the power went out in the middle of the night.
posted by vapidave at 9:32 PM on October 17, 2013 [2 favorites]


Lowering the power does not actually reduce the wattage

Unless someone invents a silent microwave with power a supply that don't make the light dim when the magnetron is on, I think most people figure this out intuitively before they're 18. However…

Actual useful information: the "power" settings on your microwave are very useful, especially with frozen items.

Even more useful for frozen items: the defrost cycle, which adjusts the cycles to be faster over time. This one I actually never figured out until paging through an instruction manual and I think there should be a public service announcement for it. Also, prompted me to start reading the instructions for my appliances. Shameful a big a nerd as me wouldn't be a power user of his non-computer items.
posted by floam at 9:33 PM on October 17, 2013 [1 favorite]


This is a lot more thought than I want to give my microwave. I use "defrost" mode and 2:00-COOK-HI repeatedly and I can report no problems whatsoever.

Ovens, ranges, dishwashers and fridges come with exacting instructions like this too. Somehow we all manage.
posted by Miko at 9:36 PM on October 17, 2013


I've wondered though: Is there any good reason why microwaves shouldn't be able to also adjust the magnetron wattage output, or PWM it quickly? It'd be useful to be able to control both the on-off-on cycling and effective output wattage. Also, I'd pay a couple dollars for: either some kind of database on the Internet my microwave can look shit up on, or a memory for often-cooked items I save manually on it. And there should be a weight sensor under the turntable.

(Wouldn't be surprised if this stuff exists and I don't know about it because I have a $40, 10 year old microwave.)
posted by floam at 9:36 PM on October 17, 2013


This may be the least controversial Mefi post of all time.

*flags, starts MetaTalk thread*
posted by lukemeister at 9:43 PM on October 17, 2013 [9 favorites]


Pope Guilty: "Who are the people who know the wattage their microwaves?

It's been printed on the front or just inside of the door of every microwave I've ever owned.
"

Or, in my case, a label on the back.
posted by Samizdata at 9:56 PM on October 17, 2013 [1 favorite]


OK, she's assuming that the cooking time should be inversely proportional to microwave power, but have the Mythbusters tested this? I think not!


By either shooting one or blowing one up
posted by mattoxic at 10:01 PM on October 17, 2013 [2 favorites]


I got a new microwave last year after 12 years with my old one, and now the only button I know how to use on my microwave is the "+30 seconds" button so everything has to be heated or defrosted at full power in multiples of 30 seconds. I read the manual and everything but after 12 years of doing things one way, I apparently cannot learn a new way. My husband understands how to do things at like 30% power for 6 minutes and 15 seconds but THAT IS DARK WITCHCRAFT.

FYI, Microwave Cooking for One has been mocked on the internet before and the author's daughter dropped in to say (summary quoted from here, can't get direct link to daughter's comment to load) "Marie Smith knew how it could be living alone, and felt that a single, divorced or widowed person deserved to eat as well as someone with a family. She had noticed the increasing numbers of single-person households in the early 1980's, according to her daughter. Marie addressed these concerns by offering free cooking classes for women who were trying to acclimate to such changes. Some were recent widows, others were homemakers entering the workforce after divorce, others were transitioning out of shelters to life on their own. Marie held many such cooking classes in her own home, and free-of-charge."
posted by Eyebrows McGee at 10:29 PM on October 17, 2013 [25 favorites]


Isn't "I don't have a microwave" guy a lot like "I don't have a television" guy?
posted by oceanjesse at 11:34 PM on October 17, 2013 [2 favorites]


Use this conversion chart to convert recipe cooking times from a 700-watt to 2600-watt microwave oven.
They make 2600 watt microwaves? Where do I get one?
posted by TedW at 11:37 PM on October 17, 2013


Found one! Just in time for Xmas!

(I have no idea why I need that much power just to reheat leftovers and defrost stuff, but you never know!)
posted by TedW at 11:41 PM on October 17, 2013


Aren't we at Ark of the Covenant levels at 2600 microwave watts?

(Hmmm, ark, arcing ...)
posted by Chitownfats at 11:49 PM on October 17, 2013 [1 favorite]


That 3000 Watt oven has an interior capacity of: One. Cubic. Foot.

Seriously, for 3000 watts (it takes a thirty amp circuit at "208-240 volts") you'd think that it would be big enough for medium-to-large cooking jobs, like roasting baby elephants.
posted by Joe in Australia at 11:57 PM on October 17, 2013


I've wondered though: Is there any good reason why microwaves shouldn't be able to also adjust the magnetron wattage output

Conventional microwave ovens have a constant output power. They are very simple designs consisting of a large high voltage transformer and rectifying voltage doubler that supplies half wave 4000 VDC and constant current to the magnetron. Constant voltage and current means constant power.

Some newer microwave ovens, called inverter ovens, have a switch mode power supply that inverts the input power to high frequency 25 KHz AC. A small transformer boosts this high frequency low voltage AC to high voltage AC, which is rectified to 4000 VDC before going to the magnetron.

The inverter power supply is more complex, requiring more components, but it has two advantages. The transformer can be much smaller and requires much less expensive copper wire. Second, it is relatively easy to control the current and voltage in the inverter and provide adjustable power output.

When you pick up a conventional microwave oven, than heavy weight you feel on the right side is mostly the big iron and copper transformer. An inverter microwave oven doesn't have that.
posted by JackFlash at 12:17 AM on October 18, 2013 [4 favorites]


Our latest microwave is 2000 watts. I simply cut the time recommended for a 1000 watt oven down to a little less than half. Then I check. If the food is done to the right temperature on an instant thermometer, (or warm enough when I touch it) fine. If not, a few seconds more.
Don't know how to thaw? Tap in a time, say 2 minutes (200). Somewhere there will be a tab called POWER. Tap that then choose what every % of power you think you need. Obviously, 5 would produce the equivalent of half power. The power is at a constant level, but the unit cycles on and off. So simple an adult can do it.
posted by Cranberry at 12:57 AM on October 18, 2013


No matter how many watts my microwave is, I doubt those watts are hitting my food.

My food is the equivalent of running around in the shower hoping to get wet.
posted by surplus at 1:02 AM on October 18, 2013


When you hit the PWR button on my microwave (which is what turns it on), it displays on-screen "900W". Pressing it again switches that to "600W", then another press to "500W" (or something like that). So, yeah, it's really easy to see the wattage.

I realized the value of using the right wattage and the right time thanks to convenience stores. Whenever I get some food at the convenience store, and they heat it up for me, it comes out perfect. Never lukewarm or overheated or unevenly heated. Tastes fresh-cooked. If, instead of having the convenience store clerk heat it, I heat it at home, it never comes out like that. Since the only two factors involved are time and wattage, and fiddling with time never produces the right results, it has to be wattage.

It also makes me think that maybe microwaves, like some other tools, are one of those things that people generally think aren't very good tools, when in reality they're pretty good, but people never actually learn to use them right.
posted by Bugbread at 2:26 AM on October 18, 2013 [1 favorite]


Some times of the year, it's just not safe for me to mess with fire (gas stove), so my boyfriend's 1990 mini microwave (16" wide, 9.5" high, 9.5" deep, exterior) from his college dorm days is the tool used most. It's been five years of learning how to do more than boil water (I recently mastered the 3.2.1 cake in a cup). It doesn't even rotate the food - the glass plate is square.

If I can figure out the wattage from the seemingly random numbers on the sticker inside, these charts will actually help. Thanks for sharing.
posted by _paegan_ at 4:08 AM on October 18, 2013


God but that was boring - reading the labels inside my microwave I'd never noticed before.

On the other hand, fab post.
posted by Jody Tresidder at 4:46 AM on October 18, 2013


My microwave has wear on exactly two buttons: minute + and the open thingy. Why would I ever need anything else? MAKE FOOD HOT and RELEASE FOOD TO MOUTH.
posted by elizardbits at 6:19 AM on October 18, 2013 [2 favorites]


Isn't "I don't have a microwave" guy a lot like "I don't have a television" guy?

Oh good, I get to be twice the jerk I was before, and I didn't even have to try harder!

There is not a single place we could keep a microwave in our itty-bitty Fisher-Price kitchen. And the house is so old, there's only one ancient outlet in there. If only we could have a microwave. Or a kitchen table. Or dignity.
posted by Coatlicue at 6:26 AM on October 18, 2013


Now if only someone could tell me what the hell the "Lunch on the Run" button does.
posted by kiltedtaco at 6:35 AM on October 18, 2013


Five minutes on high for a lump of frozen mince

read as "lump of frozen mice"; nearly vowed to kill all microwaves with fire
posted by jetlagaddict at 6:35 AM on October 18, 2013 [2 favorites]


reheat coffee

you monster
posted by backseatpilot at 7:06 AM on October 18, 2013 [1 favorite]


One Bicky Burger needs exactly 42 seconds no matter what the wattage of the microwave. Two Bicky Burgers need 53 seconds.
Yes, you can buy 10 Bicky Burgers and store them in the freezer until you're hungry. Why?
posted by Akeem at 8:20 AM on October 18, 2013


I was all ready to snark how Marie T. Smith is the loneliest person in the world, but then Eyebrow McGee's comment made me feel like a jerk.
posted by slogger at 8:33 AM on October 18, 2013 [2 favorites]


It doesn't even rotate the food - the glass plate is square.

Reminds me of my parents' old microwave, bought the year before I was born, in 1981. All it did was go for a set amount of time and then stop, and it didn't rotate the food, but it was fucking indestructible! That thing finally gave up the ghost in 2005. They've owned three microwaves since then.
posted by Pope Guilty at 8:40 AM on October 18, 2013 [1 favorite]


My mom used to have an old workhorse of a late 70s/early 80s microwave where you could open the door while it was still running and it would show no sign of actually turning off. She didn't believe me that it was a bad and wrong thing for a microwave to do.

I'm still mad about it.
posted by elizardbits at 9:32 AM on October 18, 2013 [1 favorite]


slogger: "I was all ready to snark how Marie T. Smith is the loneliest person in the world, but then Eyebrow McGee's comment made me feel like a jerk."

It's okay, I participated in mocking it the first time it was going around the internet, and then the interviews with her daughter that came out, and then I felt like a jerk. And now I feel a protective affection for the book that I have never read. :) I found an interview the WaPo did with her daughter here.

I remember another interview with the daughter, which I can't google up, where the daughter talks about these classes her mother gave, to widows and divorcees, but also to women who'd been in shelters (for homelessness or domestic violence) and women in halfway houses who'd come out of prison, many of whom were going to live in low-end apartments and might not have an oven, but would definitely have a microwave. It's sort-of a quixotic crusade at first glance, but then you're like, "Oh, yeah, that's a really good idea," and she obviously had a passionate commitment to women who were rebuilding their lives.
posted by Eyebrows McGee at 10:07 AM on October 18, 2013 [3 favorites]


For years I have proposed to friends over beer that the packaged food industry adopt a standard with something like a QR code on packaging with a reader on the microwave that will automatically set time and power level (even with changes mid-cooking) and give prompts to flip the food or vent the film upon scanning.
posted by sourwookie at 11:46 AM on October 18, 2013 [2 favorites]


-Reheating for Dummies
-Hey, Put a Pop-Tart on an Otherwise Empty Plate


Reminds me of the Brian Regan bit about the instructions for heating a pop-tart.
posted by getawaysticks at 12:25 PM on October 18, 2013


When microwaves first became common, cooking actual food in them was a thing. My parents used to have a microwave cookbook that no one had actually used in ages.
posted by hoyland at 1:00 PM on October 18, 2013


I have a 600 watt oven, but the conversion chart is mostly useless. Most cooking times on frozen foot packages are calibrated to an 1100 watt oven. I usually just double the time. But the longer the cook time, require a higher a conversion factor. A 3 minute dish will usually cook adequately in 6 min. I have one microwave lunch I like, it says cook for 6 minutes but I put it in for 20. I figure it cooks for so long that the heat dissipates before you can pump enough energy in to cook it. It's already cooling off after 12 minutes, so you have to put in even more heat to get it to cook, let alone stay warm.

The high wattage ovens are interesting. I visited a friend in about 1980, she had an industrial Amana oven, it must have been 2500 watts. I put a cup of water in it to boil and make coffee. That takes about 3 minutes in a regular oven. After about 30 seconds, I heard the superheated water explode, the cup was completely empty.
posted by charlie don't surf at 4:16 PM on October 18, 2013


> I will say that the linearity of the power regulation in the Panasonic Inverter microwave ovens is really nice.

Yes! +1. Would buy big-ass oven that's capable of heating food slowly again!

Big enough to hold a dinner plate & cover (you do re-heat with a cover don't you!?!?!11) but you can turn down the power whilst increasing the time so the heat has time to spread to the dryer parts of food.

If inverter ovens weren't available and they sold a 700 Watt 1.6 cubic foot oven I'd buy it. I heat my tea water in kettle like a civilized person.
posted by morganw at 4:52 PM on October 18, 2013


Thank you Pope Guilty for sharing our charts. For those who are wondering how to determine what wattage oven you have, there is a page at the site that explains how to calculate the wattage of your microwave oven if you lost the manual or can't find it indicated on your oven:

What Wattage Is My Microwave Oven?

Thank you, too, to Eyebrows McGee for explaining the reason my mother wrote Microwave Cooking for One. Yes, I showed up here too after the large spike in traffic to the Chart pages.

FYI, the Internet meme about Mom's book began a few years ago with this particular post at Spread the F Word:

Saddest Book Ever

You'll see my explanation when I dropped in there too.

Tracy Grant (the daughter)
posted by Microwave Cooking at 8:00 PM on October 18, 2013 [9 favorites]


OK, now for some actually useful microwaving advice.

If you take a meal in microwavable containers to work, cook for the first half upside down (but break the seal on the lid first!). As long as the meal isn't soupy, in my experience it doesn't seep out the bottom (the bottom stays pretty cold & thick through this part). Flip right-side up and finish.

If you have a two-part meal (rice & topping, for instance), heat the bottom part alone, then add the topping and finish heating.
posted by IAmBroom at 12:21 AM on October 19, 2013


Shouldn't there be an app for that?
posted by Soupisgoodfood at 12:44 AM on October 19, 2013


cook for the first half upside down (but break the seal on the lid first!)

That is utterly ridiculous. Modern microwave ovens have a turntable so the food is suspended about an inch from the metal floor. So microwaves bounce off all the walls and hit the food from all sides. This superstition might have been useful back in the ancient days when there were no turntables, the food sat right on the metal floor, so you had to stop the oven every couple of minutes and rotate your food.

This balderdash is the sort of thing I call "microwave superstitions." Back in the days when my mom got one of the first home ovens during the Amana test marketing, she would always put a jar of water in the oven after using it. She said, "what if it turned on by accident?" Well the concept that you shouldn't run the oven when empty is solid, but this oven could not turn on by accident, you had to push the start button. But even running it for a few seconds isn't going to burn out the magnetron. So all you end up with is a microwave oven that has a grubby jar of stale, bacteria-filled water evaporating in it, that you have to handle every time you want to cook food.
posted by charlie don't surf at 7:28 AM on October 19, 2013


Cute, and sciencey, charlie don't surf, but the fact remains: the top of a 2" deep container of rice gets much hotter than the bottom.

Period.

End of theory.
posted by IAmBroom at 9:24 AM on October 22, 2013


charlie don't surf: "the ancient days when there were no turntables"

Wait, 8 years ago (the age of my microwave, which was upper mid-end when I bought it) is now "the ancient days"? I figured that referred more to microwave ovens from the 1980s, not from the 21st century.
posted by Bugbread at 5:54 PM on October 22, 2013


the top of a 2" deep container of rice gets much hotter than the bottom.

That's ridiculous. Even if what you say is true, you don't want any parts getting hotter than the others. Try stirring it.

And everyone knows rice doesn't heat well in the microwave. Cooking raw rice in a microwave takes just as long as doing it on a stovetop.

Microwaves heat the water molecules directly, the magnetron is tuned to the frequency that resonates with the molecule and changes the electron spin. This is an electromagnetic phenomenon and does not occur on the surface of the food, it happens throughout the entire mass of food.

Bugbread: yes, apparently you purchased an oven designed in the Medieval Period. My previous home (almost 8 years ago) had a built in microwave above the stove. Its turntable had a variable rate motor, so that it rotated at a speed that would return it to the same position at the end of the cook time (if it was over 20 seconds or so). If you set the timer to 1min7sec and put your coffee mug in to reheat, at the end of 1min7sec you could reach in and the cup handle would be in exactly the same place it was when you started.

I remember the Dark Ages of the first Amana field tests, when there were no turntables. They told us to stop the oven and rotate the food by hand, usually once a minute. For larger foods, you might go as long as 5 minutes. Have you ever seen someone cook a Thanksgiving turkey in a microwave? My mom tried that once.
posted by charlie don't surf at 8:24 PM on October 22, 2013


cds, are you claiming that microwaved food being warmer on top and outside is a fictional phenomenon? Because that's my experience of microwaving basically forever.
posted by Pope Guilty at 10:08 PM on October 22, 2013 [1 favorite]


Microwaves do penetrate food, but they they couldn't heat the food if they weren't absorbed some distance within it. This is why the outside of a piece of food can be very hot while the inside is still cold, and it's not unique to microwaves: there are popular dishes that rely on this. Baked Alaska, for example, is a a dish of meringue-covered icecream that is cooked and served before the interior has melted.

A similar but distinct issue is that older ovens had distinct "hot spots" where the intensity of the radiation peaked. This is ameliorated by placing the food on a rotating turntable, but (a) different heights within the microwave may still be exposed to more or less radiation; and (b) that does nothing to help the problem of the radiation failing to penetrate a thick piece of food. The only ways of avoiding this are stirring the food or waiting for conduction and convection to equalise the temperatures inside the food.
posted by Joe in Australia at 11:00 PM on October 22, 2013


Charlie don't surf: Ah, wait, mystery solved. Pretty much any microwave oven sold here in Japan, except for the very, very, very low end ones, are microwave oven/convection ovens (since Japanese houses don't have regular ovens). Because they're convection ovens, they don't have turntables, because they would melt whenever you used the convection oven function.
posted by Bugbread at 12:45 AM on October 23, 2013


Pope Guilty: "cds, are you claiming that microwaved food being warmer on top and outside is a fictional phenomenon?"

No, I understand him to be saying the "warmer on top" part is fictional (or, rather, "once true, but no longer true"), because the turntable allows exposure on all sides, so the outside will be warm and the inside cold, as opposed to the old days when the top and sides would be warm, but the insides and bottom would be cold.
posted by Bugbread at 12:48 AM on October 23, 2013


charlie don't surf: "the top of a 2" deep container of rice gets much hotter than the bottom.

That's ridiculous. Even if what you say is true, you don't want any parts getting hotter than the others. Try stirring it.


Gaach... OF COURSE I don't want any parts getting hotter than the others. And I'm presenting a method that's simpler, and less messy, than stirring it. But thanks for that tip - are you some kind of cooking genius? Stir it.. Gotta remember that one.


charlie don't surf: And everyone knows rice doesn't heat well in the microwave. Cooking raw rice in a microwave takes just as long as doing it on a stovetop.

1. I'm not cooking raw rice in a microwave. Try to follow the discussion you're in.

2. My company won't install a stovetop just for me to heat rice-based meals. I suppose you could ask them...

And there are plenty of microwaves out there sold without turntables, to offices. Turntables present several extra parts to clean and break, along with moving parts. Honestly, you must imagine yourself some sort of microwave savant. Not all microwaves look like the one in your textbook.
posted by IAmBroom at 2:31 PM on October 23, 2013


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