Stir Plate Under Full Batch

Anyone know if this would be beneficial? I know it's typically used on starters but was wondering if anyone does this to keep yeast in suspension or if it improves the overall beer. Just a thought I'd never seen posted or posed before...

 

You don't want to use a stir plate for fermenting beer for 2 major reasons.

1 - adding oxygen (via stir plate) will facilitate oxidation. Keeping oxygen in the wort will also force the yeast into the reproductive stage, so you will likely have an under attenuated beer.

2 - the yeast are designed to do what they do with no (or very little) agitation. If you are having attenuation problems, try a higher attenuating yeast, or a lower floccuating yeast. It would be pointless to use a stir plate on a yeast like Ringwood or other English strains designed to ferment and drop clear very quickly.

A stirplate is designed to grow a lot of healthy yeast, not make tasty beer. For certain strains, there are benefits of rousing the fermenter when the yeast begin to drop out.

 

In addition to what Ed said, you are also likely to end up with a massive overpitch that way, which will create a totally different flavor profile. Stirplates are propagation devices.

Finally, you'd need a barbell stirbar to even have a chance of getting this to work with a carboy/Better Bottle.

 

might be an interesting experiment using two one-gallon batches side by side, one with a stir plate, the other without. Hmmm....

 

Thinking about this some more, this might actually be a good idea for super high gravity batches during the first day or so, to get maximum propagation and oxygen saturation before fermentation gets started.

 

Interesting. Glad I asked! Thanks guys.

 

I was thinking about this a while back. I figured I wouldn't use mine during the primary, even though I don't have a possibility of over-oxygenating due to using a closed system, for the reason that yeast flavor characteristics could be changed from too fast a fermentation. Starters taste nasty due to oxidation and fast fermentation! However, as earlier mentioned, rousing is good for cleaning fermentation byproducts and getting the last bits of attenuation your yeast is capable of.

I was going to use the bar for this aspect. After all, a lot of breweries use a instant maturation method of running green beer through a yeast chamber (vessel or inline mechanism containing a huge yeast population vs. beer volume to clean/mature the beer fast, filtering the yeast out after accomplished) instead of rousing for speedy packaging. I would like to use it to have all that yeast in suspension for maturation over a couple of days during my D-rest (thinking specifically for lagers but ales of course would work too). Heck, I'm about to start using gelatin. I guess it would work well for stirring that up before the settling rest prior to transfer. I say go for it, I am/will.

My only caution would be do it after the growth stage is done at the beginning of primary. Let those yeast do what they need/want to do at the beginning, then help them do what you want them to with the stir-bar. Remember, the longer you haven't let gravity do its job, the longer you have to wait for it to do its job after rousing.

 

I have thought about the same thing. I toured the Columbia Brewery in BC this summer and although the tour guide could not answer my specific questions it was obvious that they were slowly stirring the wort in their primary fermenters somehow. A stir plate large enough for my 6 gallon primaries might be hard to find and my BB's don't have a flat bottom so the idea appears a little difficult for me to accomplish.

The tour guide did mention a CO2 recovery operation at the brewery so maybe they were injecting CO2 into the primaries. Aereating with CO2 would do the job, but would take a lot of CO2.