Batch-to-Keg Size Sanity Check

[robertus]

Hi Gang

Short version: Is there any harm in putting a 1-gallon batch into a 5-gallon corny keg?

Longer version
Okay so over the last few years I've been dealing with a string of injuries that made me temporarily unable or at least hesitant to lift any sort of weight - a torn labrum in my shoulder, a sports hernia, a torn labrum in my hip resulting in surgery, and now another torn labrum in my other hip resulting in surgery (in a few weeks). I'm hopefully done with the injury train after this surgery and recovery, so I'm lookin to brew again. Figure I'll start with some 1-gallon batches, since I can do those in my kitchen and won't have to move anything heavy before my surgery or during my recovery.

I'll need to buy a new fermenting bucket, but wanted to double check and make sure I'm good to go with my current kegs. I think I am probably okay, since CO2 will displace air in the headspace and really what's the difference between this and a mostly-empty keg, but I am (as you have probably ascertained) an idiot so, y'know, figured I'd throw it out there just in case.

Based of the last surgery, I should be back at full throttle by Chirstmas or so, but wanted to get going in the meantime. It'll be nice to have a fully armed and operational kegerator over the holidays.

Thanks!

 

[AlexKay]

It’s not ideal as far as oxygen exposure goes. But if you fill and vent with CO2 a few times, you should be ok for most styles of beer. Super-hoppy IPAs and very delicate Pilsners might not have too long a shelf life.

A large fermenter with a small amount of beer isn’t a problem at all, though.

 

[VikeMan]

Short version: Is there any harm in putting a 1-gallon batch into a 5-gallon corny keg?

No harm to the beer, but it will take more CO2 (~ 14x more) to get to the same level of headspace O2 than it would with a fuller keg (i.e. w/ 5 gallons of beer), assuming you purge by repeated CO2 pressurizing/release.

I think I am probably okay, since CO2 will displace air in the headspace

If you mean that you can purge the headspace down to very low levels of O2, yes, you can. But if you mean CO2 will protect the beer from whatever O2 is left in the headspace, it won't.

 

[robertus]

Ya I meant purge-and-vent to empty out the oxygen in the keg, then fill it up and put it on the gas.

Probably not ideal, but picking up a smaller keg may be cost-prohibitive

 

[khannon]

Ya I meant purge-and-vent to empty out the oxygen in the keg, then fill it up and put it on the gas.

Probably not ideal, but picking up a smaller keg may be cost-prohibitive

Not sure what would take more CO2, but you could fill the keg with water/star-san, then push it out using CO2. Would leave only CO2. Do it right next to the sink and you won't have to lift anything.

Alternately, there are products that will let you "convert" a 2-3l soda bottle to a ball-lock "keg" Amazon.com: MRbrew 3 PCS Plastic Carbonation Cap Tee Adapter, Connect Gas Ball Lock and Beer Disconnect Simultaneously, Oxygen Free Brewing Soda PET Bottles Counter Pressure Bottle Filling Cap Handy 3-Way Adapter: Home & Kitchen should put you in the right direction. probably cost a total of ~$30 and you can use all your other equipment.

 

[AlexKay]

Alternately, there are products that will let you "convert" a 2-3l soda bottle to a ball-lock "keg" Amazon.com: MRbrew 3 PCS Plastic Carbonation Cap Tee Adapter, Connect Gas Ball Lock and Beer Disconnect Simultaneously, Oxygen Free Brewing Soda PET Bottles Counter Pressure Bottle Filling Cap Handy 3-Way Adapter: Home & Kitchen should put you in the right direction. probably cost a total of ~$30 and you can use all your other equipment.

Actually, small batch, lightweight, and cheap: this sounds like an absolutely perfect use scenario for Oxebar kegs: Oxebar Mono PET Keg - 8 L / 2.2 Gal | MoreBeer

 

[IslandLizard]

So sorry to hear about your debilitating injuries. But where's a will there's a way...

Not sure what would take more CO2, but you could fill the keg with water/star-san, then push it out using CO2. Would leave only CO2.

That^
It's called a "100% liquid pre-purge." Takes about 6-7 gallons of CO2 if you reduce the pressure to 5 psi toward the end.

Then transfer your beer from the fermenter to the keg through the liquid out post, with the PRV open (or with an open QD on the gas post) to release the CO2 inside while it fills. In the end you'll have a keg containing 1 gallon of beer and 4.3 gallons of CO2 on top. It will carbonate fast, even faster with a few minute rolling.

Key is, the lid stays on the keg so no air (oxygen) can get in! Do not open that keg until you need to thoroughly clean it.

When kicked, for most beer you may not even have to open the keg to rinse/clean it.

 

[seilenos]

Have you considered fermenting and serving in the keg?

 

[Jayjay1976]

Hi Gang

Short version: Is there any harm in putting a 1-gallon batch into a 5-gallon corny keg?

Longer version
Okay so over the last few years I've been dealing with a string of injuries that made me temporarily unable or at least hesitant to lift any sort of weight - a torn labrum in my shoulder, a sports hernia, a torn labrum in my hip resulting in surgery, and now another torn labrum in my other hip resulting in surgery (in a few weeks). I'm hopefully done with the injury train after this surgery and recovery, so I'm lookin to brew again. Figure I'll start with some 1-gallon batches, since I can do those in my kitchen and won't have to move anything heavy before my surgery or during my recovery.

I'll need to buy a new fermenting bucket, but wanted to double check and make sure I'm good to go with my current kegs. I think I am probably okay, since CO2 will displace air in the headspace and really what's the difference between this and a mostly-empty keg, but I am (as you have probably ascertained) an idiot so, y'know, figured I'd throw it out there just in case.

Based of the last surgery, I should be back at full throttle by Chirstmas or so, but wanted to get going in the meantime. It'll be nice to have a fully armed and operational kegerator over the holidays.

Thanks!

Should be fine so long as you carefully purge with CO2 before filling. Hope all your labias heal quickly so you can get back to brewing full batches.