general principles of piercing the protective cover of unfrozen microwave ready meals

Question

The microwave ready meals I tend to eat all say the same thing: pierce the protective plastic cover before heating at %POWER%, usually around 800W for %TIME%, usually 4-5 minutes. Most of them say to use a fork to make around half a dozen holes in them. I've tried using a fork multiple times and it usually just gets stopped by the plastic, sometimes even bending the container around it. My forks might be too blunt...

My usual way now is to stab in a dozen small holes all over with the tip of a cheap paring knife, often even straight through any paper label that's glued onto the plastic, to ensure a proper spread. That does the job, but I wonder if I'm making holes that aren't big enough, or that I'm making too many holes, or that they're the wrong shape. I've also in the past tried to open up a corner of the packaging, but last time I tried it, with a paella, the rice felt noticeably dryer.

I'm probably overthinking this, but the question I have is: are there general guidelines for piercing this cover to improve the heating process?

Answer 1

I assume it is simply to allow some steam to escape during heating, so that you don't have a big mess to clean up when the "balloon" pops, or, as Chris H wisely points out below, a potential burn when you unseal the container after heating. I think your strategy of poking a hole with a knife a couple of times will be sufficient.

Answer 2

2-in-1 Trick: Don't Pierce, Lift a Corner of the Cover.

While piercing the cover to allow steam to escape is the recommended approach -- on the packaging -- it's not the best solution.

The next step, once the meal is heated, is to peel the plastic cover completely, so you can access whatever is inside. Except that now the container is hot, the plastic cover is hot, and you're burning your fingers if you try to peel it by hand. A few knife cuts to get most of the cover out of the way is a possibility, of course, but those leftover bits of plastic get in the way when tipping the container...

Instead, I therefore prefer to pre-lift one of the corners of the plastic cover prior to heating:

1. It lets steam escape, just as piercing the cover would.
2. Once the container's hot, I can relatively easily peel the cover, without burning my fingertips.

You'll want to peel the cover not diagonally, as it tends to tear up, but instead following the edges (where it's "glued") going clock-wise or counter clock-wise.

The technique is especially valuable if you have a "multi-parts" meal. If you make holes everywhere, you won't be able to tip the container afterwards without the content leaking through the holes. By lifting corners, however, you can peel the cover for a single part at a time, and tip the container to your heart content. This makes it much easier to present the meal nicely on a plate.

Note: if you have multiple parts independently sealed, you need to lift at least one corner per part...

Answer 3

It would be difficult to poke too few holes. The purpose is to allow steam to escape, preventing a potentially dangerous buildup of pressure and hot steam. Even a tiny hole should allow pressure to equilibrate, and the slightly elevated transient pressure during cooking won't make much of a difference. At worst, you might need to leave the food in the microwave another couple seconds after the elapsed time to let built-up steam escape. Personally, I have never seen a microwave meal explode even without holes poked in it.

Putting too many holes in the film could cause the food to cook improperly if the steam simply escapes rather than cooking the food.

Answer 4

I suspect that the problem piercing the plastic with the fork is because of the way you are holding the fork.

When you pierce the plastic with your fork, angle the fork so that one prong of the fork hits the plastic first. That way when the full force of the initial impact is concentrated in a small area which will pierce the plastic. If the fork is perpendicular to the plastic then the force is distributed among the typically three or four prongs, so you would need three or four times the force on the fork to have the same effect.

Answer 5

There are two purposes for the holes - first, as others have pointed out, is to allow steam to escape. Second, the heated steam itself assists in cooking the food. So on this second point, I poke my holes near the center of the tray. Since microwaves heat from the outside in, the centre of the tray would heat the least, so directing the steam towards the middle of the tray would help the food heat more evenly.

Answer 6

I used to hold the fork by its handle, but it got messy occasionally, and for that reason used to go for a sharp knife.

One day it dawned on me to hold a fork near the end of the prongs, and slanted at an angle as if the single prong that I use to pierce with is an extension of my index finger and my thumb held together. Basically in this position I can sense/orient my hand, my fingers, the fork and the plastic well, and I get a lot of control with my hand and fingers. This allows me to use just the right amount of force to break open the film, not to mention it's safe compared to using a knife.

There may be other positions to hold the fork that are mechanically more efficient, but may not give you the same degree of control for your motor system to react in real-time to packaging variations.

I usually punch around a dozen holes, but it's more habit than a determination of an optimal number.

Answer 7

Since I live alone I do a lot of stuff in the microwave and have found a sharp knife works best. To appease my slight OCD place 6 evenly spaced. Since most of my food is frozen the solid mass stops the knife going in too far - the slit is normally between 2mm and 4mm long. When doing non-frozen I simply pull back as soon as the blade pierces the film although this does tend to give longer slits. This also works when doing a portion of frozen veg in an old ready meal container covered in micro safe cling film.