I'm achieving a rather bizarre sense of enlightenment and was hoping someone could explain the impact that force carbonation in a keg vs. force carbonation in a keg with eventually bottling off would have on a beer.

I ask this because I am now on my second beer, this one being an IIPA (Belgian yeast) that I've bottled straight from the keg after it being in the keg for 3-4 weeks, and now that I just cracked one, 2-3 weeks after putting it in the bottles, it tastes profoundly different than when it was in the keg.

I will admit that the hop aroma is dying off (which frankly, given the amount of dry hopping I did, is probably a good thing), the flavor is still mostly there, but it seems a lot more well-rounded and not as disjointed as it did while it was in the keg (bubble gum aroma, not much hop flavor, enamel stripping bitterness, it all seems to be centering on each other into a balanced mix now).

Is this just the effects of aging? I saw the same thing with a smoked porter using peat malt. I kegged it at the same time I did this IIPA, and had I not known that I put peated malt in it, I never would have tasted it. After I bottled it (again, same day as this IIPA, I used 4-5% peated malt), and let it sit until last Thursday, it tasted like someone encapsulated the entire Amazonian rain forest after being burnt to the ground by a bunch of torch wielding 7 foot tall blonde beauties all in one bottle. I never got that sense of flavor when it was kegged, not even close, and I'm depressed that I drank almost all of it before I could get this flavor out of it.

What gives? Is it just age? Does bottling with less head room for the CO2/beer to breathe have some sort of effect on flavor? Is something else at work?

  • bottles generally age faster than the keg, meaning they will get smooth faster, but also spoil faster. you can experience the concentration of more yeast flavor in a bottle, too, such as with bottle conditioned hefeweizen, most Belgian beer, or other bottle conditioned beers. I have had some dry hopped beer where they add hops to the bottle conditioning, as well, leading to a concentration of whatever flavor develops.
    – DaFi4
    Commented Oct 21, 2018 at 7:49
  • one more note, smell and taste a bottled beer right when you crack it. Then wait 2 minutes and try again. You might notice the smell/taste changes as it gasses-off. Also if a bottle was hot and then chilled, it can taste different right after chilling or after a week of chilling. I think more gasses are released when hot and more are absorbed back into the liquid when chilled for a long time. Priming sugars can affect the taste, too in bottle conditioning.
    – DaFi4
    Commented Oct 21, 2018 at 7:52

1 Answer 1


There are many small things at play, but only one major difference. When you bottle from a keg, the CO2 level in the keg will be higher than that in the bottle. You lose some CO2 during bottling. (The higher the number of volumes, the more you'll lose ... also, the higher the temps the more CO2 lost). When bottling for competition this is even truer - but this is due to serving: pourings are small, swirled, left out for a time, etc.

In terms of flavor in the long-term, bulk aging will allow all the beer to age together while aging in bottles may cause different flavors in different bottles. Yeast may still be at work, but this is less likely under pressure.

It almost sounds as though you have the common problem of kicking the keg just as the flavor is peaking. The only difference is that you notice it while the beer's in bottles - the flavor either peaks or has passed its peak. Do you ever taste them side by side (ket, bottle) after the beer has been bottled for a month or so?

It's hard to say for sure why you're noticing what you're noticing. Flavor changes during aging are pretty complex -- hop aroma loss is the most understandable, but even that doesn't make a whole lot of sense when the beer's totally sealed up. Flavor compounds break down and change over time and even the experts can't fully explain it.

  • I had to downvote becasue of you do it properly there should be no difference in CO2 between keg and bottle.
    – Denny Conn
    Commented May 26, 2013 at 16:27
  • @Denny, the OP mentions transferring from keg to bottle, where some CO2 is lost - that was the crux of this answer.
    – mdma
    Commented May 26, 2013 at 18:33
  • Agreed, but the answer was general, not specific to the question. That was why I downvoted.
    – Denny Conn
    Commented May 26, 2013 at 18:41

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