Fermenting in corny kegs

[pete20]

I'm a big fan of fermenting right in a corny keg, both primary and secondary. Hooking up a CO2 tank and doing a keg-to-keg transfer makes racking so much easier that with a carboy and siphon.

For primary fermentation I just remove the pressure release valve, stick in some plastic tubing that fits tightly, put the other end in a jar of sanitized water, and it works just fine.

My question is about the secondary fermentation. That's where I get lazy, skip the blow-off hose, and just pull the pressure release valve every day or two. Do I stand a risk of contamination/oxidization if I keep doing that? My last few batches have been Ok, and I figure CO2 is heavier than air so it should blanket the beer, but I was wondering if any one has experience with this. Should I even bother pulling the release valve?

 

[MalFet]

Your call with the pressure, but it should be okay either way. You'll get different fermentation character under higher CO2 pressures, but it can work. There's a description of pressurized fermentation on the wiki. What is your secondary fermentation? Fruit?

 

[pete20]

No fruit or anything. My beers just seem to benefit from separating out the trub. They're definitely clearer and less of a yeasty taste.

I don't know why no one has come up with an airlock that screws into the release valve. Seems like it would be a great product.

 

[bigljd]

It's not quite the same as what you talking about, but you could get one of these:

http://www.homebrewing.org/Cornelious-Keg-Lid-for-Secondary-Fermenter_p_999.html

 

[stunsm]

I don't know if the airlock like that is really necessary. I ferment exclusively in cornies, for most beers I just attach a blowoff tube to a spare gas disconnect and put the end in a jug of water/sanitizer. I was worried that this may not release the gas fast enough, but there never seems to be any real back pressure when I pull the relief valve. For extremely hoppy or high gravity beers, I'll take the poppet/dip tube out of the gas connection on the keg, as well as out of the disconnect. It doesn't seem to clog this way, and as long as you use the same disconnect for your co2 when you transfer the wort, you shouldn't have any issues.

 

[beeber]

I don't recommend pulling the relief valve every so often. I did that with a batch of wine and it was major league oxidized.

If you reverse the CO2 in tube you can hook up a piece of hose to this and then put an airlock in the hose.

Don't get lazy with this, it's not worth it IMO.

 

[stunsm]

I don't recommend pulling the relief valve every so often. I did that with a batch of wine and it was major league oxidized.

Are you sure this was the cause of the oxidation? It seems to me that if even a slight amount of back pressure is released when you pull the valve, then the headspace should be a cushion of co2, and the odds of any appreciable amount of air entering, much less contacting whatever you are fermenting, would be pretty slim.

 

[beeber]

stunsm,

I can't think of another thing that would cause the pronounced sherry flavors in the wine. I am careful when I transfer and have not had any other instances of oxidation.

My theory is that there is a temperature difference between the room and the liquid when I opened the relief valve. The liquid, being cooler, would cause fresh air to be sucked into the keg and mixed inside. This found it's way down into the wine.

 

[electric_beer]

stunsm,

I can't think of another thing that would cause the pronounced sherry flavors in the wine. I am careful when I transfer and have not had any other instances of oxidation.

My theory is that there is a temperature difference between the room and the liquid when I opened the relief valve. The liquid, being cooler, would cause fresh air to be sucked into the keg and mixed inside. This found it's way down into the wine.

I could be wrong, but isn't sherry flavor sometimes associated with infection? I'm pretty sure it is in beer.

 

[beeber]

It definitely was darkened. I have no doubt it was oxidized.

http://www.wine-tastings-guide.com/wine-tasting-terms.html

Oxidized - Most wines should not be oxidized, which is caused by excessive exposure to oxygen. Sherry, most notably, is made in a way that encourages oxidation, and thus oxidized wines are also described as "Sherried" as well. If you don't know what Sherry smells like, it tends to have a nutty aroma. Oxidized wine can also generally be somewhat flat tasting and darkens in color, turning brown.