Continual stirring

[Sorry for posting two threads today, if the moderators find it disagreeable I apologize]

Why is it that I can't find any info on fermentors with some kind of stirring device built in? It would seem sensible to keep the yeast suspended and to keep the mixture homogeneous. It would allow for better temperature control as well. People speak of healthy yeastcakes but yeast is a single celled organism so it sounds sensible that they would compete with eachother when they are too close together.

I got this idea while using a magnetic stirrer in my university's laboratory a few days ago, there are also stirrers that are just rotors that can be lowered into the reaction mixture.

It's not necessary. The yeast know what to do!

During an active fermentation, yeast aren't just sitting around at the bottom of the fermenter, they're getting churned up. Take a look inside a carboy during fermentation. As fermentation finishes, you want them to be able to drop out of suspension. I would imagine that having a stirring mechanism *might* slightly speed up the fermentation process, and maybe help out during a stalled ferment, but those are relatively minor concerns for most of us.

The biggest issue that I see, though, is that you'd be aerating your wort after fermentation has started, which is something you really don't want to do. Many people use magnetic stir plates for making their starters (which work great), but they also have the effect of continually aerating the starter wort. That's no big deal for a starter (actually, it's a good thing), which is going to be pitched into a larger wort and the O2 will get used up - but that's something you absolutely do not want to do once fermentation has started in the main wort.

It's also something else that would likely be a PITA to clean/sanitize.

with an airlock the aeration wouldn't be a problem wouldn't it? and a magnetic stirbar is extremely easy to sanitize! In the lab we put them in caro's acid or aqua regia to remove all traces of organic matter from previous reactions. In case of brewing I suppose sulfite or H2O2 bleach would work just fine. A magnetic stirrer would be a pretty easy thing to build. All it takes is a few magnets and a fan.

I might just do this!