The double wrap, once in plastic and then again in foil probably makes it work. Same as you can boil water in a plastic cup over an open fire. As long and the r

The double wrap, once in plastic and then again in foil probably makes it work. Same as you can boil water in a plastic cup over an open fire. As long and the ribs are sufficiently moist, the steam will keep the plastic below melting temps and foil will reflect a lot of infrared. They make microwave steamer bags out of plastic, and even pre-made pork chop oven bags. Modern plastic wrap is also supposedly free of all the leachable nasty phthalates and stuff of yesteryear. I can see it working out. That said, I don’t understand why double wrapping ribs would be any more effective than well crimped foil wrapping.