Should I use my microwave's 'popcorn' button? My microwave oven has a "POPCORN" button. Its manual reads:


  Touch this pad when popping popcorn in your microwave oven. The oven's sensor will tell the oven how long to cook depending on the amount of humidity it detects from the popcorn. See page 31 for more information.


Page 31 clarifies:


  POPCORN lets you pop commercially packaged microwave popcorn.


(As opposed, I suppose, to popping kernels in a paper bag, which I also do.) Fine. Other microwave ovens have a similar button (though I must admit I haven't checked their manuals).

The problem is that my "commercially packaged microwave popcorn" bag reads:


  Do not use popcorn button.


I've seen it on other microwaveable popcorn bags, too.

So... which of the two manufacturers is correct, and why? And why does the incorrect one claim what it does?
A better instruction would be "do not rely entirely on the functionality of the popcorn button on your microwave, since microwaves vary widely as do bags of popcorn." But that's longer, and kind of complicated, so they abbreviate it "do not use popcorn button".

There's no problem with the power setting of the popcorn button, only with the timing. You should hang around near the microwave, and when you hear the pops slowing, stop it, no matter what your popcorn button thinks. And if you get a lot of unpopped kernels, and the popping didn't slow before the button said the microwave was done, consider doing it yourself next time and letting it pop for a little longer.

The problem with leaving it in too long is that the corn scorches (usually from the centre out) and the whole bag is inedible. If the energy is no longer going into popping kernels, it's going in to scorching what you already have. Get it out before that happens.