Oh the bubbles kinda look like fat, but it was just your standard simmer scum mostly. In my experience, fat doesn't evaporate, but sometimes it kinda emulsifies into the simmer. I think that could help though, trying to skim off some fat in the beginning and reserve it for the final frying leg. But I also used pork from Whole Foods, and I've been finding that it's just kinda too lean for some of the old pork recipes I'm used to. I think this recipe may be geared for a fattier meat.