This evening I attempted to make gjetost. I started with a gallon of milk and made mozzarella, then added a little dry milk, and made ricotta. Finally I was going to reduce the whey down into gjetost.
Once I got the whey reduced down to about 10% of its original volume, the simmering became incredibly... weird? Basically the bubbling became very erratic, and at least twice there was a sudden "BLUB" which sent showers of 230+ degree whey showering across the stovetop, also making a noticable SLAM when the pot physically jumped on the stovetop. After narrowly avoiding a bunch of burns twice, I moved the pot off the heat and walked away. I want to make the recipe but I'm not risking a trip to the hospital.
So, has anyone ever seen this happen? Why does it simmer so erratically and then have one big GLUB/bubble explosion in the center that is so violent? I've heard of things getting super heated, but that doesn't seem like it would apply here because it's not a completely pure liquid (there are some curds of albumin protein which would seem to be good origination sites).