Does Purging C02 release Aromatic from Dryhopped IPA's

[quaboagbrewing]

I had my latest IPA sitting with 20psi for 48 hours and lowered the pressure to 12psi for the next 4-5 days. When lowering the pressure I had to purge out some C02 from the Corney's. Am I losing aromatic every time I need to purge from the keg? In my way of thinking by purging C02 I am just releasing aroma from the head space above the beer and not sure how this would cause me to lose aromatic since I am drawing the beer from the bottom of the keg......unless all that aroma in the headspace would have been absorbed in solution and that's what I have just released. Can someone clarify this for me and if the answer is yes that I am losing aromatic how do you combat that when you need to drop C02 to serving pressure?

 

[philipCT]

It's an interesting question - never occurred to me before. I don't know if aroma is "lost" per se, but I think we're likely talking about very small measures. Probably too small to do any kind of legit test, if you wanted to get a real answer to the question.

Scientifically, if I were to pretend I was a scientist, I would say that aroma consists of particles suspended in the air that are detectable as smell. So, I might say that certainly, if you smell something wonderful when you blowoff that high-PSI pressure, you are "losing" aroma that might otherwise hang about and arise out of the head of the beers you pull from that keg.

Given that, if you are genuinely concerned about it, you might consider just not burst carbing your IPAs and adopting set-and-forget carbonation instead.

 

[joshesmusica]

+1 to everything above

 

[raouliii]

I had my latest IPA sitting with 20psi for 48 hours and lowered the pressure to 12psi for the next 4-5 days.

Here is my no purge, burst carb, technique. I will initially establish how many turns of the regulator knob are required to increase from the serving/carb psi to the burst psi. When it's time to reduce pressure, I decrease by that many turns. Since the beer is still absorbing CO2, the pressure will slowly drop down to serving/carb psi over the next day with no purging required. I have check valves in my CO2 lines, so even if the corny is overfilled above the gas-in tube, I don't get any backflow.

 

[Rev2010]

If the aroma is coming out with the purge then it's already out of the beer. So no, you're not losing anything IMO. And of course the purge will smell like whatever beer you have in there.


Rev.

 

[doug293cz]

If the aroma is coming out with the purge then it's already out of the beer. So no, you're not losing anything IMO. And of course the purge will smell like whatever beer you have in there.


Rev.

If the aroma molecules are in equilibrium with the beer (basically the headspace is saturated with the aroma molecules) so that no more come out of the beer over time, then venting the headspace will release some of the aroma molecules. After venting the headspace will no longer be saturated with aroma molecules, so more will be able to come out of the beer.

The above is independent of any time dependent degradation of the hop aroma and flavor compounds in the beer.

Brew on

 

[Rev2010]

If the aroma molecules are in equilibrium with the beer (basically the headspace is saturated with the aroma molecules) so that no more come out of the beer over time, then venting the headspace will release some of the aroma molecules. After venting the headspace will no longer be saturated with aroma molecules, so more will be able to come out of the beer.

For any of that to matter you would need to scientifically know for one what the aroma saturation point is for the headspace, the current saturation, and the aroma off gas amount over time. Because if the saturation point isn't already met, and if the saturation point wouldn'tbe reached by the time he started drinking it, then it wouldn't matter what comes out with the purge as he may just lose the same amount as if he didn't purge.


Rev.