My Steam was brewed Sunday. At first a thin layer of foam appeared on Tuesday and it started to bubble away. Today, when I got home, there was all sorts of the particulate from the bottom that floated up and attached itself to the krausen. Then, as I watched, the particles broke away from the krausen and sunk to the bottom. In the meantime, the beer looks like it has "currents" in it, with all of the yeast balls going in circles, sinking (mostly) and swirling. Airlock is bubbling every 2 to 3 seconds. I haven't seen this on my other brews (this is my 3rd). Does this have anything to do with the fact it is lager yeast (even though the fermentation temp is 58 - 65 degrees)?