Sierra Nevada Brewing Company released a timelapse video of the open tank fermentation process used to make their famous Bigfoot Barleywine. For those of you who have never seen a high gravity beer fermentation this may seem pretty chaotic. The stainless steel vessels are cleaned, sanitized, then filled with cooled wort on which the yeast is pitched. The bubbly foam you see moving around on top/spilling over the side is referred to as the krausen. This is yeast and wort proteins, along with unfermentables and hop resins. It usually sticks to the side of the fermenter, and in this case spills over the sides of the vessel. Pretty amazing to see this process in timelapse! Great video Sierra Nevada!