How high to fill kegs is optimal?

[grathan]

-If you could fill right to the brim would you or would it be better to toss out some beer?

I have done this before and it did cause problems with beer being able to siphon back out gas hose. It also introduces a slight chance of infection from the crevices in the keg top (and gas hose). It also seems to take longer to carbonate having less surface area where gas can penetrate. ALso pulling the vent on a full keg can be ugly. One plus of filling completely is less headspace which means less co2 used to flush and less oxygen in the keg.

Of course a full keg also takes longer to kick, with some beers this seems to take forever.

But maximizing the system seems important as well. Spending a whole brew day for a half-filled keg seems wasteful. But it also has some advantages. Like:
-Being able to just dump trub into fermenter and not having to worry about getting a full 5 gallons.
-Freeing up a keg that much sooner means more brew days and hence better brewing skills which means even better tasting beer.

Perhaps 5 gallons isn't even close to the lid..

I know I am over-thinking my ideal batch size, but not having one set has left me short-handed and over-abundant unpredictably so many times. So just looking for some thoughts on how high to fill kegs, thanks.

 

[Yooper]

It should be filled to under the gas "in" diptube. Some have cut their diptubes, to put more beer in it, but I haven't. The cornies hold a bit more than 5 gallons, about 5.25 I guess because I haven't measured it but it's more than an even 5 gallons. I've filled them up half way when making a half batch, and it didn't take any longer for them to carb than the ones with 5 gallons in them.

Filling past the "in" tube can mean that beer backs up into the beerline and the regulator, so that's not a good idea. The inside of the keg is sanitized, so infection risk to the beer wouldn't be an issue, but ruining the regulator would be an issue.

 

[FuriousE]

I like to put any extra beer that won't fit into a keg into a plastic PET bottle (like an empty 1 or 2 liter soda bottle) and carb it up using the carbonator cap. This way, I can start drinking it much more quickly as I don't have to wait for the keg to carb up. I usually plan my batches to about 5.5 gallons into the fermentor, which usually gives me 5 gallons into the keg plus 2-3 liters into PET bottles.

 

[day_trippr]

Can't believe this is an actual question

Cut the gas dip tube down to just a nub beyond the flange.
Then you can fit an extra quart or so without risking gas-line blow-back...

Cheers!

 

[grathan]

That's a pretty neat idea. My original thought was to just err on the too much beer side and bottle the rest, but there is actually a bit of stuff to clean just to bottle. I think the PET thing will work nicely. thanks for that tip.