Beer Forum

I've recently started fermenting in converted pony kegs (7.75 gallon SS kegs, aka - slim quarter kegs). When I mentioned this at my LHBS (MoreBeer - Riverside, CA) I was told that doing this could cause fermentation problems. I have fermented about 4 beers using these vessels and haven't noticed anything wrong. Just curious, does anyone out there know what kind of problems would come from using a slim quarter keg as a fermentation vessel?

Cheers,

Darin

Did you ask them why? Not sure what concerns they'd have in mind... You may get different character from the fermentor geometry, or they may be concerned about stuff getting in crevices and leading to contamination...

It was something to do with the vessel being so narrow. I didn't think it was that much more narrow than a carboy...... maybe by a couple inches.

Narrower vessel means more liquid above the yeast, meaning more pressure on the yeast towards the bottom of the fermentor. This can result in the different character I was referring to based on geometry. However, this is something that you can account for as you get more comfortable with your set up and system.

I think the effect of fermentor geometry (i.e., hydroistatic pressure) at this scale is negligible at best. I mean hell, the difference between a 6.5 gal carboy and a 5 gal carboy is probably about the same as mentioned by the OP, and I use them interchangibly with no noticible effect.

Either the LHBS fella has his head up his ass, or he was thinking about something different than this.

~widget

Buttwidget wrote:I think the effect of fermentor geometry (i.e., hydroistatic pressure) at this scale is negligible at best. I mean hell, the difference between a 6.5 gal carboy and a 5 gal carboy is probably about the same as mentioned by the OP, and I use them interchangibly with no noticible effect.

Either the LHBS fella has his head up his ass, or he was thinking about something different than this.

~widget

I agree. I'm thinking he might have had his head up his ass.

For the volumes that we do, it won't make a bit of difference. If you were fermenting a 10 barrel batch in a three story tall skinny tank then it would be a problem. Think about what the hydrostatic pressure must be in ordinary commercial fermenters. There are several feet of liquid above the yeast. They have no problems at all. Yes, someone does have cranial rectitus.

Agree with everyone. There is no difference in pressure for a 5 gal batch. The surface area that the floating yeast is exposed to is smaller by a fair bit smaller. But if you see slightly lower attention you could rouse the keg durring the first 4 days. Just a thought.