Can you have too much head............................space?

[Bad Goat Brewing]

Is it possible to have too much head space? I think I remember hearing the pros shoot for 25-30%. what about if you fermented 11.5 gallons in a 27 gallon conical? That would be 68% head space, could that be too much?

[Ozwald]

I wouldn't recommend it, but provided your cleaning/sanitizing practices are solid you shouldn't run into any fatal issues. I don't because my conicals don't seal & it takes too long to fill up that much headspace with CO2. I aim for no less than 2/3's.

[Kbar]

How about making sure to purge with CO2. Of course after you completely oxygenate the wort first.

[Bad Goat Brewing]

How about making sure to purge with CO2. Of course after you completely oxygenate the wort first.

You mean just purging the fermenter every so often after fermentation is complete?

[Kbar]

No, should only take one purge. After that, the yeast will create the necessary CO2 and further purge the head space in the fermentor. I am assuming that the issues people are afraid of are wild yeast/bacteria carried in so much head space full of the stuff we breathe. Use your C)2 tank, assuming you have one, to purge this volume of head space until the yeast kick in and do what they do best.

[adamK]

One issue with purging with CO2, though, is that the yeast are taking up oxygen from the headspace. If you purge before they are done growing, you could negatively impact the yeast growth, and thus not have enough yeast. I would think you would want to purge after the beginning of fermentation (if at all).

I would think that if you hit your wort with O2 in the fermenter, that *should* help minimize the bugs from the air.

[Ozwald]

No matter what you're purging with, you're asking for trouble. The CO2 blanket isn't all that protective against bugs, it's a barrier against O2 after fermentation has started. Provided it's undisturbed, it'll do a pretty good job, but you're really looking for active fermentation to keep producing CO2 which will keep pushing O2 out. The layer of krausen will better protect against 'bugs' over CO2. I'd just advise against it in general, but like I said before, if you trust your cleaning/sanitizing you shouldn't run into any fatal issues. Just double batch to fill it up & don't worry about it.

[Bad Goat Brewing]

The reason I was asking is I intend to buy a conical, and I usually put around 11-16 lgallons in the fermenter. I like the Morebeer Conicals, but they only sell 14 and 27 gallon models. So If that much head space is a problem, I need to look at other manufactures.