Pressure in a conical fermenter

The pressure control for conical fermenter

Utilizing conical tank for fermenting, it without pressure at the begining. In order to emission bad taste of volatile substances. When recycle CO2 adopt slight pressure(lower 0.01-0.02MPA). In the later period of fermenting that outsight fermenting level reach 70% close the tanks. Gradually increase the pressure to 0.08MPA and mke CO2 saturate into beer. Early increase pressure result in faster yeast settlement and not good for diacetyl reduction.

Pressurized fermentation always accompany with high temperature fermentation. Though high temperature fermentation (higher 13℃) can speed up fermenting rate. But yeast proliferation strong and will produce excessive metabolic byproducts. It will influence beer quality. High temperature fermentation can avoid it by pressurized measures. To control pressurized time is important when pressurized fermentation. If early, yeast proliferate will inhibit and influence fermenting speed. If late, also will increase byproducts produce. So it is suitable to gradually increase pressure by section. Yeast inoculation without pressure, control temperature at 10-12℃. When fermenting level reach 25%-30%, gradually increase pressure to about 0.03MPA. Then increase fermenting temperature to 16℃，the pressure also increase to 0.16MPA.

What will cause negative pressure in the fermenter?

Many breweries today prefer to cleaning the fermentation tanks with hot water or sterilizing the tanks with steam, actually it is very dangerous.

Under ordinary pressure, the weight of 1M3 steam is 560g, but the weight of 1M3 water is 1ton. If the steam is condensed, its volume will reduce to 1/1786 of origin. Which may cause negative pressure and make the tanks dangerous.

Besides, if the discharge speed is much faster than the air flowing in speed; Or when the fermentation tanks washed by hot caustic liquid, the CO2 absorbed by the caustic liquid and caused volume shrinkage; Or the tanks washed by cold water after it is just showered by hot liquid etc. All these operations will cause negative pressure in the tank. So the temperature for cleaning the fermenters better not exceed 40℃.