How Much Oxygen Should Dissolve In The Wort?

How Much Oxygen Should Dissolve In The Wort?

As we all know, plenty yeast is required for beer fermentation. 

While much oxygen is required for yeast propagation. 

So we should provide enough oxygen during yeast propagation. 

Often the oxygen is provided from the sterile compressor air.

The yeast will be propagated much if the oxygen is too much( more than 12PPM). 

That will cause beer taste too light. 

But it will affect the yeast function if the dissolved oxygen too small( smaller than 6PPM). 

So how much oxygen is good for yeast propagation?

8-10mg/l(8-10PPM) is required according to beer brewing technology, 

that is about 3l/hl sterile air in theory. 

As some part air bubble can not be dissolved in wort, 

so we often suggest 5-10 times sterile air in real production. 

For example, 0.03m3 sterile air is required for 1000l wort in theory, 

but often 0.15m3 (even 0.3m3) is required in real brewing.

The compressed air should be broken to small bubble, 

thus they can be dissolved in cool wort completely. 

We also suggest compressed air mixing with wort in reverse to ensure enough contact time.