fundamental question regarding stir plates

[william_shakes_beer]

I have been brewing for several years. I have a stir plate and 2L eflask and always do starters from my ranched yeast cells.

Recently I have been toying with the idea of making a stir plate that would receive a 7 gallon brew bucket containing a full 5 gallon batch, as an alternate to shaking the fermenter after pitching the yeast. Run it say for the initial 12 hours of fermentation.

Does the stir plate oxygenate the (starter, beer) by keeping the cells in suspension and circulating them into the surface where they have an oppoetuity to take up o2, or is a vortex that pulls o2 into solution required? i usually get a vortex and successful fermets, so I'm not sure which action is actually oxygenating. In a 5 gallon bucket, acheiving a vortex, even with a massive stir bar, is unlikely.

 

[cbenn22]

A stir plate works by continually mixing the wort and thus increasing the amount of surface area of the wort that is exposed to the air. The yeast cells themselves don't actually take up o2 when they are on the surface, but o2 is dissolves into the wort at the surface where the yeast can then use the o2. The vortex is not necessary, but it does ensure that the wort is continually being circulated so the transfer of gases occurs.

 

[Cyclman]

Something like this: http://www.stir-plate.com/BlackMAXX.htm

It is a cool idea.