Oxygen effects

Oxygen is required to assure a healthy cell multiplication.

Three different methods are used for oxygenation.

  • Top filling and splashing against fermenter walls
  • Aeration
  • Direct oxygen injection 

It is usually recommended to make the oxygenationation on cooled wort.

At this stage, hygiene is critical since bacteria may develop during aeration.

Oxygen should only be added in the first twelve hours of the fermentation (9 ppm).

Adding oxygen during the late fermentation will increase aldehyde levels and amplify diacetyl formation. High levels of oxygen will suppress ester production. It has been noticed that oxygen can increase SO2 concentrations in some worts.