We have said the word susceptor roughly 10,000 times in the past year, and finally I am going to explain what it is and why we don't use it. I touched on this in the bag dissection post but it's worth shedding a little more light on this.
This is going to hurt a little, but you need to know a little bit about how microwaves work to get the rest of this. Microwave ovens use a radio frequency that is tuned to heat up water. That's it. It's a radio wave not too different from what is sent out by radio stations. It was actually discovered when a worker noticed that the candy bar in his pant pocket melted when he stood in front of a airport radar dish. Okay, enough history.
Popcorn that is submerged in a pool of hydrogenated oil (or sometimes palm oil), as is the case inside most microwave popcorn bags, doesn't contain all that much water. The microwave only heats water. To remedy this the scientists put a metal coated patch in the bag that basically shorts the radio waves to make a ton of heat and get the kernels to pop more quickly. That's why it's in there.
The issue is that the susceptor is made up of paper coated with aluminum flake (or metalized film, or graphite) and PET (Polyethylene terephthalate - the same plastic use for most soft drink bottles). It gets incredibly hot so the chemicals in the paper, plastic, glues, and metal are more likely to be released. Also, the heat often causes the plastic and metal to burn off or delaminate. You can see that happened in the above photo. So where does all that crap go? Where else can it go? Into your popcorn.
There are other nasty details about the existing microwave popcorn bag, but that's just about enough negative for me for a while. I will eventually write about PFOAs which are substantially worse; so much so that the FDA and EPA both are trying to stop the use of this chemical.
That said, I don't want to come off as an alarmist. The existing microwave popcorn bag is pretty gross and chemical laden for sure, but in the end you need to make the call.As you probably expected, we are not using any of these things in our bag. It's made from paper and only paper. It can mean that sometimes we get a few more dud kernels, but we think it's worth it.