jbock220
Well-Known Member
Does anyone stir plate a primary?
Does anyone stir plate a primary?
- Thread starter jbock220
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I believe that has been discussed quite a bit. You're making beer, not producing yeast, so continually introducing o2 into your wort isn't a good idea.
microbusbrewery
Senior Member
Check out the Black Maxx thread, https://www.homebrewtalk.com/f11/5-gallon-stir-plate-274067/
Just so I understand what you're asking - stirplate your brew while it's fermenting in the primary?
Have you ever tasted the beer that's made when doing a starter on a stirplate? If you want really nasty tasting, heavily oxygenated beer, go for it (or just go buy some Natural Lite).
Have you ever tasted the beer that's made when doing a starter on a stirplate? If you want really nasty tasting, heavily oxygenated beer, go for it (or just go buy some Natural Lite).
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jbock220
Well-Known Member
So definitely separate your starter yeast from the rest of the liquid before pitching? Otherwise we'd be introducing the oxygenated beer from the starter.
Hogarthe
Well-Known Member
Papazian claims agitating the fermenter will cause fusels and other problems. this wasn't in "The complete joy of homebrewing" but his other book. I've never tried it, and never saw a reason to.
It all depends on the style of beer you're making; higher gravity, better to have more 02. But in general you can't even get the beer to absorb more than 4-5 ppm of O2, if you're just shaking in normal air. For ideal yeast viability you want 8-10 ppm of O2, so I'd imagine stirring in primary with an airlock might get you closer to ideal from any O2 left in head space. Even then it would be pretty much impossible to over oxygenate much less oxidize the beer as long as your airlock is in place. Remember it's all about O2 balance; under oxygenating stresses yeast too!
TheZymurgist
Well-Known Member
Starters are small in comparison to the overall volume of beer. If you're making something light, like a pilsner, then you would want to decant. If you're making an IPA or a stout, then there's no need as the flavor of the beer itself would cover up any off flavors from the starter.
Having sufficient O2 early in the process is very important to yeast growth, production of various amino acids and the formation of cell walls in the new "daughter cells". Once anaerobic fermentation begins, however, the introduction of additional O2 into the fermentation has a detrimental effect.
I dont see how can you introduce more O2 by stirring wort/beer in close (airlock) carboy. There is O2 at the beginning of fermentation (dissolved in wort and in the headspace) but rather quickly this O2 is used by yeast in aerobic phase, and co2 is produced. With constant CO2 production there is no fresh O2 getting in to the carboy, i bet even when fermentation is done and agitation is moderate there will be very small chance of dissolving some co2 back in to the wort and creating negative pressure in the headspace and suction of air through the airlock. So i dont believe oxygenation would be a problem, agitation may speed up fermentation by keeping more yeast in suspension but i have no idea how this would change the metabolism of yeast thus change flavor profile.
starters can be almost 10% of the beer volume (2 liter starter in a 23 liter batch, AKA 5.5 gallons). you're probably safe pitching the whole starter, but definitely better to cold-crash it and decant. it's not hard and it eliminates the risk that the nasty oxidized starter beer brings with it.
I never pitch more than a 1 L starter directly into the wort (~5% total volume). I otherwise would always decant. 5% of the total volume is way different from aggressively aerating the entire batch throughout fermentation.
