Thoughts of stirplate for primary?

I was thinking if a stirplate will help starters ferment efficiently, what about using one for primary and secondary also?

I still use buckets to ferment in, so I don't think that I could just drop a stirbar in the bucket, but I thought about putting a glass plate in the bottom of the bucket with the stirbar on that.

dumb idea?
-J

No, it's not a dumb idea. However, I think you are missing the difference between a starter and the primary fermentation.

You pitch a starter to make more yeast. You don't really care what becomes of the wort, so you ferment at room temperature and try to get things done quickly. As long as you wind up with a bunch of yeast.

You pitch a primary to make beer. You care quite a bit what happens to the wort, so you control temperatures and manipulate the fermentation in other ways. You aren't as concerned with time as you are quality, and you aren't concerned with maximizing yeast production.

If you were to put a stirring plate in the primary, you might get a faster fermentation and a larger yeast cake. However, I don't know what you would get for beer. It seems like the best case scenario would be that you get no better quality. Even when you get a stuck fermentation, a single, simple rouse usually gets it going again.


TL

Hmm... I always thought you had to be careful not to introduce oxygen to the beer once it has started to ferment. I.e. be careful racking, bottling, etc. Stirplates just constantly keep oxygen in the beer...

Oxygen, post fermentation, leads to oxidation, correct? Or am I missing something here?

There has to be a reason noone, including commercial breweries, do this.

Yep, I'd guess you'd end up with horrible oxidation and not a lot of alcohol.

When yeast have oxygen, they use it to multiply. When they don't, that's when the serious fermentation happens. So you want as much oxygen as possible continuously available in the starter to make as much yeast as possible, but that would be a very bad thing in your beer.

The problem here is not O2. There won't be any to be drawn into the wort if you cap the fermenter with an airlock.

The problem is, as TL pointed out, the fermentation charachteristics of the beer. They won't be the same. For one attenuation will be higher since even a highly flocculant yeast remains in suspension longer.

I once came accross a paper that discussed forced circulation in a commercial setting. It was here http://www.asbcnet.org/journal/abstracts/2002/0712-01a.htm. But back then I as able to read it w/o having to pay. They must have fixed this hole.

For the home brewer, forced circulation could work well for high gravity beers where you want to keep the yeast in suspension after the initial strong fermentation until a desired attenuation is reached. It certainly would help me with my Doppelbock right now. It just has a hard time to get me the last 2 *P towards my final gravity.

Kai