It seems she's demonstrating the experiment with different temperatures and different ginger juices. There are two temperature ranges and two ginger juice types (one filtered and one unfiltered old ginger). The only success case is the one with unfiltered ginger juice at certain temperature. I'm guessing the unfiltered juice has ginger starch/fiber in it which helps the milk to crystallize at the right temperature. Crystallization requires "seeds" to serve as the nucleus to start the process.
I'm guessing two essential factors are temperature and some fiber material like ginger root. Other fruits with the right kind of fiber might work too.