Left it for two weeks at 2.3 bar (35 PSI) and 17 C (59 F). Poured a 2 liter bottle, it made beer-like pleasant foams upon pouring but it had almost no sparkles to the taste bud. Should I let it sit for more or search for leaks again (already searched twice with both soap cream and the set-pressure-and-see-if-it-drops-after-some-days methods) ?



I should note that even a 10 ml (this is no more than a Tequila shot) pour for only tasting yields not much acid to the taste bud, so I think my problem comes mainly from lack of H2CO3 to begin with. Oh, and I am not using a bar tap, but a butterfly valve that already has a one footer tubing attached to it (of around 1/4" inner diameter).

  • 1
    It sounds like CO2 is coming out of solution too quickly somewhere in your process. We'll need some more detail to diagnose exactly where. Were you carbonating it in that 2 liter bottle, or did you transfer it from a keg into that bottle? If you transferred it, did you get the foam when filling the bottle or pouring from it? Did you use a counter-pressure filler or pour it from a tap into the bottle?
    – Simon
    Commented Nov 6, 2018 at 19:57
  • @Simon transferred from keg to bottle, got foam while filling the bottle, only a tap used.
    – kellogs
    Commented Nov 6, 2018 at 23:04

3 Answers 3


Your cider was flat when you drank it because it lost much of its CO2 when you were transferring it from the keg to the bottle, as evidenced by the foam.

The gold standard for filling bottles from a keg without losing carbonation is a counter-pressure filler, which pressurizes the bottle with CO2 before filling it with beer, so that the CO2 stays in solution. That's an equipment investment you'd want to make if you're commonly bottling entire batches or large portions thereof.

To fill bottles without a counter-pressure filler, first make sure your draft lines are balanced. If you can pour a pint from the tap without excessive foam, then you can consider filling a bottle from that tap. If not, then you need to either chill your keg and reduce the pressure to balance it with the resistance of your draft lines, or use longer lines (not really practical for 35 psi).

Once your draft lines are balanced, you'll need to be a little more careful when filling a bottle as opposed to a pint glass. A growler filler or even a length of 1/2" inner diameter tubing slipped over the tap will help you fill the bottle smoothly, minimizing the amount of carbonation lost to agitation. Fill the bottle as near to the top as you can, and cap it tightly and quickly. It should hold carbonation like that for a week or so.

Addendum on "balance"

Having your draft lines balanced means they provide resistance to match the pressure in the keg, so that the beer/cider pours slowly and smoothly. There are many questions on this site on the topic of balance and line length. Here's some additional reading that will walk you through the calculations behind it: https://www.kegworks.com/blog/determine-right-pressure-for-your-draft-beer-system/

At 35psi, you'd need about 50ft of 1/4" vinyl tube to provide enough resistance. Your valve might be able to make up for a shorter length of tubing, but the turbulence around a partially open valve can also cause CO2 to come out of solution and create foam.

Since colder liquids absorb CO2 more effectively, you can get the same volume in solution at a lower PSI. That's why I recommend chilling your cider and reducing the pressure, so that you can get it out of the keg with a more reasonable amount of tubing. This could also help if your cider truly hasn't carbonated properly yet, and it's not just CO2 loss during bottling.

  • Hey, thanks for the detailed answer, one question and a remark. What do you mean by balanced lines ? Is the balance a certain ratio between line length and serving pressure (and maybe temperature as well) ? Edited the question too
    – kellogs
    Commented Nov 7, 2018 at 8:32
  • Alright. Done the maths and... I am getting 0.7 PSI serving pressure :D. So if I were able to drastically reduce the pressure to those level (doable with the regulator) I should be getting proper carbonation. Good thing I have already poured sugar inside the keg... which did not start re-fermenting but still... doh!
    – kellogs
    Commented Nov 8, 2018 at 17:46
  • 1
    I'm afraid that cranking the regulator pressure down to practically nothing won't solve the foaming on its own. If you try to push the cider at a much lower pressure than that which it was carbonated at (or rather, would be carbonated at for its current temperature), it will still foam a lot. This condition is frequently referred to as "overcarbonated". I think you'll still need to chill it or add tubing to tame it.
    – Simon
    Commented Nov 8, 2018 at 18:43
  • Geez.. this is tough. I should have stuck with the old PET bottles, sugar prime and be done with it. I could change some tubes, no idea exactly how as I do not know the current carbonation level. But how am I supposed to chill down a 50 litter keg ? Hmm... the winter is around the corner... can these kegs take negative temperatures ?
    – kellogs
    Commented Nov 8, 2018 at 22:08
  • 1
    That would be an excellent subject for a new question! My guess would be as long as the beer doesn't freeze, the keg would be fine. I have no personal experience with chilling a keg outdoors, though, and as a fellow resident of a cold-weather climate I'd be interested to see the answers to that.
    – Simon
    Commented Nov 9, 2018 at 15:44

All that I needed was a beer conical (bar) tap instead of the regular ball valve one that I have bought from the hardware store. Problem solved.


Consult a carbonation chart, also called a forced carbonation chart. It will tell you what is the correct "set it and forget it" PSI, based on your desired level of carbonation and the temperature in the cooler, or room. I often have as many as 8 kegs connected to a single 50 lb. tank and they take between 5 and 8 days to be fully carbed. Best thing is, if you forget about it, or can't get to it for some reason, you are in no danger of over-carbing your beverage. If your regulator is set to the appropriate pressure as indicated by the chart it will simply maintain it at that level of carbonation.

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