Injection Tank
The cooled wort (liquid extract) is delivered to the fermentation cellar where it is stored in the injection tanks. Yeast slurry is added (pitched) into the tanks, initiating the primary fermentation process. The temperature in the tank must be strictly controlled to maximize the fermentation process. Sterile air or oxygen is injected into the bottom of the tank to support the living yeast and ensure that all sugars are consumed by the yeast and converted to alcohol. The primary fermentation process takes between 3 to 5 days to complete.
Figures
(Source: http://www.snyderindustriestanks.com/Products/Chemical-Injection-Tanks)
Videos
Chemical Injection Tanks - 75 Gal Vertical, 130 Gal Protector Tank, & 125 Gal Horizontal