I made some burton bridge from a kit and secondary-fermented it in a 25 litre keg with a tap and a cap capable of taking a CO2 cartridge holder (none was fitted) I left it in our warm utility room (circa 22°C) for five days to second-ferment with a standard amount of sugar then it was stored in the garage between 16-20°C (daytime). No leaks evident anywhere as the pressure was normal initially.

By the time the barrel was half empty the carbonation seemed less and the beer a bit flat, certainly different tasting to initial pours. I'm just taking a pint glass at a time rather than filling a jug.

Any advice on why this might be happening?


2 Answers 2


my best guess is no leak, but as you pour, if you dont continue to keep the pressure constant, the carbonation will come out of solution, and you will continually get flatter and flatter beer as you pour more.

example would be drink half of a 2L of soda, then let it sit with a cap on. in a day or 2 you'll notice the pressure will go up, and the soda will be flatter.

My advised is buy a co2 cartridge to keep the carbonation up and the oxygen out.

  • Exactly, pressure is lost in the empty space of the key.
    – Philippe
    Commented Sep 14, 2018 at 17:55

As beer is dispensed, you get more and more headspace. That headspace has to be filled with something. If air can come in from the outside, it will, and oxidation will change the taste of your beer. If the system is sealed, some of the CO2 which was dissolved in the beer will be pulled back out as gas, reducing your carbonation.

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