Where To Measure Dissolved Oxygen In The Brewery

Once in the brew kettle, boiling removes dissolved gases. This de-aerated wort is then normally cooled to around 10°C to 15°C before transfer to the fermenter. Yeast is then added together with oxygen to allow yeast growth.

Air contains roughly 4/5th nitrogen and 1/5th oxygen. If air is injected into the wort in an unpressurised fermenter, the wort will at most contain 8-12 ppm oxygen, depending on the temperature.