How whirlfloc (carrageenan) can make fermentation appear. The cold and hot break have coagulated into ‘bits’, so when the yeasties are doing their magic, the bits fly around.

Whirlfloc is a purifed form of high molecular weight carrageenan extracted from red marine algae (Rhodophycae) and manufactured exclusively for use as a wort fining agent. It accelerates the formation of dense and compact hot and cold trub, saving time, boosting wort recovery and resulting in considerably brighter worts. source: Brewing Solutions