I started doing this recently, and will never look back at the microwave techniques!
Could too high heat be the culprit? I’ve noticed that if I don’t lower the heat after those initial 4 kernels, the popcorn has more of a styrofoam-like texture. Edit: going beyond my speculation, I googled a bit. Excess steam might be the culprit, so make sure there’s enough ventilation in your pans, but I guess not so much that kernels whiz out.
