Topping up part drank keg?

I've got 6 gallons of a lager currently in the fermenter. My intention was to keg a gallon and bottle a gallon to give to people (as is my normal practice).

I am now thinking that I'd like to be able to have all of this on keg, so I'm wondering if it would be possible to rack 5 gal to a keg and the remaining gal into a small glass carboy, then allow it to sit next to the keg so continue to lager whilst the keg sits there. Then once I have drank about a gal or so I will rack the carboy into the keg to fill it back up?

I know that I will be adding flat beer to carbonated beer, but I don't mind just leaving it once full to come up to the correct carbonation again?

Thanks

Sure, that'll be fine.

Are you going to add the new lager to the keg by racking from the carboys through the liquid out post? That would be best to avoid getting air (oxygen) in your keg. While racking, leave the PRV open or stick an open gas QD on the gas post to vent. That way there is no need to repurge the keg either. It takes an absurd amount of CO2 to purge a keg that's not full.

IslandLizard said:

Sure, that'll be fine.

Are you going to add the new lager to the keg by racking from the carboys through the liquid out post? That would be best to avoid getting air (oxygen) in your keg. While racking, leave the PRV open or stick an open gas QD on the gas post to vent. That way there is no need to repurge the keg either. It takes an absurd amount of CO2 to purge a keg that's not full.

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I hadn't really considered how I would do it, but that makes sense. How would I go about adding it via the liquid out post though, would I need to do it under pressure i.e. from another keg?
Thanks

mattsearle said:

I hadn't really considered how I would do it, but that makes sense. How would I go about adding it via the liquid out post though, would I need to do it under pressure i.e. from another keg?
Thanks

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You can do it with gravity, keg on the floor, carboy on table/counter. Or by applying carefully very low CO2 pressure (1-2 psi) to your carboy using a carboy cap. Once you've got beer in the hose, attach it to the liquid out post (QD).

Now there are numerous ways to limit the amount of air transferring into your keg. One is to first prime the racking hose with beer, before attaching it. Or run CO2 through the tubing then attach, etc. Or push and pull.

IslandLizard said:

You can do it with gravity, keg on the floor, carboy on table/counter. Or by applying carefully very low CO2 pressure (1-2 psi) to your carboy using a carboy cap. Once you've got beer in the hose, attach it to the liquid out post (QD).

Now there are numerous ways to limit the amount of air transferring into your keg. One is to first prime the racking hose with beer, before attaching it. Or run CO2 through the tubing then attach, etc. Or push and pull.

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Ok great thanks mate, I'll give it a try!

mattsearle said:

Ok great thanks mate, I'll give it a try!

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Good luck and plan ahead.

You could try it out first with a spare keg and a bucket or carboy with some water. There are a few details that may come up while you do it, so you can be be prepared when doing the real thing. For example, I found it very difficult to keep beer in the racking hose while attaching it to a QD AND do it all in a sanitary way.

You can always ask here or look around for info.
I wonder why a few others haven't chimed in already. We all do this weird stuff at some point.

I rack from fermentors into the liquid post on a keg, using an auto siphon. Makes starting the siphon trivial and sanitary.

geejay said:

I rack from fermentors into the liquid post on a keg, using an auto siphon. Makes starting the siphon trivial and sanitary.

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Sure, as long as you don't blow all that air from the empty siphon and hose through the keg. So prime first, filling the siphon and tubing, clamp off and mount to the post. Then let it flow.

Do you have a spare keg? I would just rack the gallon into that one and drink it first instead...

IslandLizard said:

Sure, as long as you don't blow all that air from the empty siphon and hose through the keg. So prime first, filling the siphon and tubing, clamp off and mount to the post. Then let it flow.

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That's a good point. I actually haven't been purging my siphon, but I'm sure I'll consider it next transfer. I'm thinking about starting to ferment in corny kegs so I can do sealed keg-to-keg transfers.

PGEduardo said:

Do you have a spare keg? I would just rack the gallon into that one and drink it first instead...

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I may have a spare one by the time it rolls around, as I have one that's close to kicking. I hadn't really thought about doing that but if it's kicked by then I may just do that and keep it simple!