Lawrence Brewers Guild

I am carbonating a Tripel to ~ 3.5 volumes and set my pressure at 20psi and kegerator at 36-38 and let it go for a week and a half. I then took it off the CO2 (I did not test it at that time) for another couple of weeks to let it age further and to finish off another keg. After I cleaned out my lines and hooked it up again to my serving pressure of 12-14psi, it was practically flat. So I juiced it up to 25psi for a day and tested it again. No change. Left it for a few days more. No change. Then I cranked it up to 30psi and left it for a day. No change.

So what the hell is going on? Has anyone encountered this before and what did you do to fix it?

I have done the StarSan spray test countless times and I would have probably run out of CO2 by now if there was a leak. So what gives? It's a decent tasting flat beer but is it too much to ask for a properly carbonated beer?

I will gladly offer a bottle or two of this delicious brew to anyone who can help me solve this. Thanks!

First your PSI for desired volumes is correct for that temperature, provided you kept it closer to the 36.
When you pulled it off the CO2 to let it age was the keg kept at 36-38 degrees? It was allowed to warm that would change things.

Also you may not have let to set long enough, 3.5 vol is a lot of carbonation. The 3 volumes is generally the highest any beer goes. From 3 to 3.5 at that temperature is a difference of about 5 psi ( 20% increase ) in psi to achieve the desired volume. You may need to let it set for 3 weeks or more attached to the cO2 to achieve that carbonation. If you didn't get to the desired carbonation before removing the CO2 you never will without adding more CO2 to the system.

Finally it's best to have your serving pressure the same as your carbing pressure, unless you can cash the keg in a week or so. Eventually the system will equalize and you'll loose all that carbonation you've worked for.

I've got a simple question.
Are you carbing from the bottom up or top down?

Also did you use the "set it and forget it method" or "the Shake method"?

Top-down I assume and the set-it and forget it method, although I did lie the keg on it's side and shook it for a few seconds when I jacked it up to 30psi.

I think I'll let it set for another week at the proper psi and then see where we're at.

Also, I thought once it was carbed, it was carbed, ie, it won't lose co2 or co2 won't fall out of solution if it is sealed. And that also means that I can set my serving psi lower than the psi it took to carbonate and not worry about it.

Thanks for the feedback.

Okay, this is probably a stupid question, but are you HEARING the gas go into the keg? I mean, when you crank a regulator that high and open the tank, you should hear the gas flooding in. If you're having NO change on the amount of carbonation when you taste it, then you're simply not getting gas into the keg, so I'm thinking maybe your regulator is plugged somehow? At that pressure, even warm beer should uptake the CO2 given the amount of time you're talking about.

Another important tip that Frank already mentioned is that any liquid will absorb and hold CO2 more efficiently the colder it is. Warm beer will take much longer time to absorb the CO2. And it will hold CO2 less easily. So as you drink it and create headspace in the keg, it will leave suspension and fill that headspace.

Also Andy's excellent tip about putting gas in through the diptube (out) will also increase surface exposure to the gas as it bubbles up to the headspace, making it absorb more quickly. It's that, or shake the crap out of it. :)

Matt

dbüscher wrote:Also, I thought once it was carbed, it was carbed, ie, it won't lose co2 or co2 won't fall out of solution if it is sealed.

Correct however, it's not a sealed system. Each time you pour a pint you are breaking the seal. Since took 20 psi at 36f to achieve 3.5 volumes of dissolved CO2, as you remove beer that volume is replaced with CO2 at only 12-14 psi. Diffusion dictates that eventually the CO2 in the beer will fall out of suspension until the pressure of the CO2 in suspension is equal to that of the CO2 in the space above the beer. That's why I mentioned cashing the keg with relative quickness. I tend to have a keg on for a month or more (maybe I should have more beer drinking friends over) and if I lowered the PSI from that of which I used to carb, the beer would be flat at the end. 13 psi at 36f is ~2.7 volumes so that doesn't seem to be your problem here.
Second if it wasn’t fully carbed before you removed the CO2, the pressure of the gas will continue to force some CO2 into the liquid until they equalize. With a full keg there’s not a lot of gas volume to begin with so it will quickly equalize and very little additional CO2 will be forced into suspension. If it is fully carbed (the pressure of CO2 applied has equalized with pressure of the dissolved gas) and it’s removed it will stay carbed in a sealed system.
I still think it just didn't get enough time.
Bottom up carbing would be if your gas system has threaded fittings you can hook up the CO2 to the “out” post with a liquid disconnect and force it through the dip tube. This isn’t the best idea, you have to make sure you have a one-way valve or risk damaging your regulator. Or you have a diffusion stone system that hangs a stainless steel diffusion “stone” in the bottom of the keg from the gas tube. Think of a bubble stone in a fish tank. It breaks the CO2 up so it absorbs faster.

I've bottomed up carbed since I started brewing without issue. Threaded connectors are a must. And possible backing up of beer into the reg. is a possibility. Just bleed the keg before hooking/unhooking and it isn't a issue. I do have check valves (as everyone should regardless) in my system.

Usually 36-48hrs, 35-38*, 20psi, bottoms up gets me where I like to be without even thinking about it again.

As far as your issues, Frank pretty much summed it up.

Btw, dont shake, set it and forget it is the best method. Who wants big bubbles that disappear? That's what shaking will do for you.

Really interesting feedback from everyone...

My beer was moderately carbonated but would become flat after a few minutes and had 0 head. I know that there is co2 flowing into the keg so there is no clog in the regulator. Also, the keg has been stored in the fridge consistently since it has been on co2, including the period where I took it off the gas.

Anyway, I just now rigged it up like Andy said since I have threaded connectors...we'll see how the bottom up method works.

Blktre wrote: Btw, dont shake, set it and forget it is the best method. Who wants big bubbles that disappear? That's what shaking will do for you.

There was a great Brewfest discussion about this last year around a campfire with Barry. When you shake a keg, it will carb quick, but the bubbles are big and go away quickly. They will also produce a slight metallic flavor to your beer, something to do with carbonic acid or something like that (it was Saturday night after all, but if it was Friday night, I would have zero recollection of the conversation). I carb from the top down, but do so at a max of 15psi and let it sit for a minimum of 5 days if not longer. I've also noticed I get better carbonation after 2-3 pints have been drawn. Not sure if it's because it is still slowing carbonating, or if a little bit of head space helps it out.

+1 to Andy for suggesting the bottom-up method. Within 24 hours I had near perfect carbonation...totally transformed the beer from nearly undrinkable, which tasted like a moderately carbed wine, including a hot/sweet/bitter alcohol flavor, to a well-rounded, full-bodied Tripel that goes down light and smooth. And that hot-alcohol flavor has been replaced with that patented warming effect you get from a proper high alcohol brew (around 9.5%).

Bottom's up is one way. Just remember time, temp, and pressure all need to be consistent. Colder the better.
If going top down consider a higher pressure for a longer amount of time.

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