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Keg Filling Questions?

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  • Keg Filling Questions?


    I've been working at a brewery for about a year and a half now and coming into the industry with only homebrewing experience. We have been having issues with beer being fully carbonated in our brite tanks but as soon as it hits the keg it becomes flat and some seemingly oxidize. We only filter two beers and wondering if stability is a problem because of that in that regard however we are sending tests out to figure out stability. My issue is predominantly the beer becoming flat and I'm wondering what precautions y'all use to prevent this. We manually counter-pressure fill kegs and its about a 15 minute process each keg which seems to be about average with everyone. I am wondering what pressure you have in brites while kegging, how much you pre-pressurize kegs to, and what other procedures you may have to ensure quality. our protocol is this:

    -Kegs are stored at around 60 degrees ( no space to put them in refrigeration)
    - cleaned and sanitized kegs get brought to conditioning room where we hook up to racking arm on brite tank that sits around 12psi (we serve off brites and the lines are fairly long, about 30-40 feet).
    - with gas valve closed we let kegs get equalized to tank pressure, our kegs are also pressurized below our tank pressures
    - wait until equalization and crack gas valve open very slightly to slowly allow to fill
    - once beer foams out of gas valve, shut valve and hook up a new one.

    Each keg is about 15 mins time total, and doesn't slosh after fill. We have an Alpha Dog keg washer and it pressurizes the kegs, to i believe 6 psi.

    Also wondering if anyone has experience with this manifold,

    Thanks in advance, all input is appreciated

  • #2
    That sounds about right. A couple suggestions:

    - Has the carbonation level been verified in the brite/serving tank? It may be on the very low end and still acceptable in the glass, but the time you transfer it to a keg and invaribly loose some carbonation it may fall under that threshold. Are you able to evaluate the level with a zahm or other meter?

    - I would bring the keg pressure on your keg cleaner up to 2psi or so below your tank pressure. No need to be quite that low. You may be knocking carbonation out with that initial fast fill prior to the tank and keg equalizing.

    - Once a keg is full, you really should be able to open the gas-side of the filling coupler all the way and see liquid beer coming out rather than foam. Also, make sure when the keg is full you close off the gas-release on the keg and let the keg equalize to the tank pressure, which should only take a couple seconds if the keg is full. If you are under-filling your kegs and they are at a much lower pressure, the dissolved CO2 will exit the beer until the new equilibrium is reached with the headspace. Best to weigh your kegs to verify your fill levels until you get it dialed in.

    - Are you able to raise your tank pressure at all during kegging? This is a bit of a tricky question if these are serving tanks too and, depending on your draft system, may affect how beer pours if you are kegging at the same time. Ideally, you never want the tank to drop below its equilibrium pressure based on your carbonation. Say your beer is at 38°F and 11psi (~2.5 vol/co2) anytime that tank drops in pressure will cause sublte (or more) foaming and gas release. Imagine cracking a can of beer open as the extreme example of this - big pressure release and foam/carbonation release. Also, this can stir up a tank bottom in extreme cases. Regardless, bring up that head pressure if you can. Plus, you can package quicker becuase of it.

    - When you say flat - does it actually seem like there is little to no carbonation in the beer or just no head? Just trying to rule out the dirty glass scenario

    - You also mentioned oxidation. We have an Alpha Dog Keg Washer also. Ours was an early model and was originally set to push the sanitizer back into the holding vessel with compressed air instead of CO2. Also, ours used to just use a timer to pressurize the keg for the very last step of the cleaning process. Now, it's been reprogrammed to use CO2 for that last liquid evacuation and we've installed a digital pressure gage that allows us to target a specific psi rather than an arbitrary fill time (which, depending on your CO2 use throughout the brewery, may change the final pressure the keg arrives at). If you are seeing oxidation in your kegs, you may need to bump up your CO2 purge times prior to pressurizing the kegs.

    Hope this helps!

    Last edited by BemidjiBrewing; 12-10-2019, 12:25 PM.


    • #3
      I'm gonna echo the comment above, and encourage you to do your final sani purge with CO2 (it's not that much more expensive, really), to make sure any headspace is pressurized to serving pressure, and to make sure you're filling your kegs. You can either check for liquid beer on the overflow, or put your kegs on a scale to check fill weight. It doesn't really take much un- or under-pressurized headspace to cause significant carbonation reduction, especially if your beers are relatively low in carbonation to begin with (which seems to be the case with most craft breweries around here). Other than those issues, your process seems fine.


      • #4
        KEGS NEED HEADSPACE - could be the cause for valve damage

        One of the most common sources of damage to kegs and valves today is the practice of overfilling kegs and omitting the required headspace. Please reach out to our friends at Micro Matic regarding this practice and they can share with you a short pdf that explains in detail why kegs need headspace.

        All the best,
        Chris Sapyta
        CEO - Keg Logistics

        Steve Bradt
        MICRO_MATIC Regional Sales Manager
        Office: +1 (888) 453-4776
        Mobile: +1 (785) 766-1921
        Keg Logistics


        • #5
          Hi Chris,

          Are you able to post that PDF of keg filling from MicroMatic, or supply a link?

          I've never heard that kegs need headspace - is this in the event of freezing? If headspace is required, how is this best determined? Weight?

          Thanks for any info you can pass along!