Kegging at half the capacity

[gpalkar]

Quick question:

If I have an x gallon keg, would it be possible to force carbonate x/2 gallon batch?

 

[jack13]

I plan to do this very thing in the near future for the first time, so I'm interested in what others have to say.

But I can't think of any possible reason that it would be a problem.

 

[cubalz]

Short answer: yes. You will just be using a lot of CO2 to take up the empty head space. You will also need to take steps to get the oxygen out of the headspace so your beer does not oxydize.

 

[Yooper]

Sure. You need a bit more gas, but it's not an issue doing it.

 

[Qhrumphf]

Yes it will be fine. And it will carbonate faster as well.

This happens in commercial breweries CONSTANTLY in their brite tanks (say, putting a 10bbl batch into a 20bbl brite tank). Same exact concept.

As said, you'll need to be extra careful about oxygen due to the increased headspace, however if you're purging properly in the first place that shouldn't be an issue.

And while it will take more initial gas to get the keg up to pressure, the overall gas usage shouldn't be significantly different, in fact a bit less by the time the keg is empty. You're dissolving less into solution in the reduced volume, and filling the same total empty space.

(Well I guess that depends on how you purge and fill- you could use a bunch more gas if you purge afterwards, but if you're purging pre-fill and never opening the keg so there's no need to purge afterwards it'll make zero difference)

 

[4of7]

Quick question:

If I have an x gallon keg, would it be possible to force carbonate x/2 gallon batch?

50l kegmenter, I am doing 10 gallon batches,

 

[balrog]

I know someone who regularly bottles half, kegs half, 5G batches, 5G corny kegs. Done it myself a couple of times, but I don't play too hard with O2 exclusion nor do I make many highly hop flavored styles.

 

[IslandLizard]

To avoid wasting a lot of CO2 to purge the huge leftover headspace, to lower the O2 content to reasonably low amounts to prevent oxidation over time, look into 100% liquid pre-purging a keg, and filling it through the liquid out post and never remove the lid. We use this method for closed and semi-closed transfers.

For example, purging a 5 gallon keg with only 4 gallons of beer in it (1 gallon headspace) uses the same amount of CO2 as a 100% liquid prepurge of that same (5 gallon) keg. The former method leaves an undesirable high amount of O2 behind while the latter (100% liquid prepurge) leaves no O2 behind, or a very minimal amount.
The stats on a half filled keg are much, much worse.

 

[krenshaw]

To avoid wasting a lot of CO2 to purge the huge leftover headspace, to lower the O2 content to reasonably low amounts to prevent oxidation over time, look into 100% liquid pre-purging a keg, and filling it through the liquid out post and never remove the lid. We use this method for closed and semi-closed transfers.

For example, purging a 5 gallon keg with only 4 gallons of beer in it (1 gallon headspace) uses the same amount of CO2 as a 100% liquid prepurge of that same (5 gallon) keg. The former method leaves an undesirable high amount of O2 behind while the latter (100% liquid prepurge) leaves no O2 behind, or a very minimal amount.
The stats on a half filled keg are much, much worse.

i'm assuming you mean to use sanitizer instead of "liquid." That works great in practice, though depending on how much the sanitizer costs it may not be more cost effective. I've done transfers both way with smaller kegs and haven't any noticeable O2 pickup as long as you are careful.

 

[IslandLizard]

i'm assuming you mean to use sanitizer instead of "liquid." That works great in practice, though depending on how much the sanitizer costs it may not be more cost effective. I've done transfers both way with smaller kegs and haven't any noticeable O2 pickup as long as you are careful.

Yes, usually a sanitizer such as Starsan, but regular (tap) water can be used after the keg was properly cleaned and sanitized. That is if one normally drinks that water without getting sick.

I understand the cost of Starsan being an issue if one dumps it at the end of each use. But it can be stored in a closed bucket or spare keg for weeks, months, possibly longer.

 

[shelly_belly]

I make 1 gallon starters for lagers and then ferment them out under temperature control the same as 5 gallon batches. I keg them in 5 gallon kegs and force carbonate. No more throwing that expensive DME wort down the drain!

 

[IslandLizard]

I make 1 gallon starters for lagers and then ferment them out under temperature control the same as 5 gallon batches. I keg them in 5 gallon kegs and force carbonate. No more throwing that expensive DME wort down the drain!

How does that unhopped/underhopped and oxidized starter beer taste?

I drink starter beer too, only containing its very low natural carbonation from the process, but a pint is usually more than enough before I switch to real and good beer. It often isn't too bad, just refreshing, low alcohol, and it gives me a good feedback on the yeast's character.

 

[IslandLizard]

I make 1 gallon starters for lagers and then ferment them out under temperature control the same as 5 gallon batches. I keg them in 5 gallon kegs and force carbonate. No more throwing that expensive DME wort down the drain!

How does that unhopped/underhopped and oxidized starter beer taste?

I drink starter beer too, only containing its very low natural carbonation from the process, but a pint is usually more than enough before I switch to real and good beer. It often isn't too bad, just refreshing, low alcohol, and it gives me a good feedback on the yeast's character.

 

[shelly_belly]

I lightly hop it. I also push it via CO2 in to a properly purged keg. Basically I make it the same way I make all of my beers only from DME instead of all grain. I'm pretty amazed at how good they turn out.

 

[IslandLizard]

I lightly hop it. I also push it via CO2 in to a properly purged keg. Basically I make it the same way I make all of my beers only from DME instead of all grain. I'm pretty amazed at how good they turn out.

You don't use a stir plate, you let it ferment out just as a regular beer, airlock and all? That would indeed give you a much better tasting starter beer, yup, like a mini batch to pitch the yeast cake from.

 

[shelly_belly]

Yes. Mini lager. I usually try to make it similar to what I'm pitching the yeast in to to kind of give me a preview of the bigger lager. I still use the stir plate on ales.