My hoppy beers get more bitter after tapping

[PhillyBrewer]

I've noticed that my hoppy beers/IPAs taste good when I first tap the kegs, but after a few weeks on tap, the bitterness increases and ends up being quite harsh. What is the cause of this? Any way to prevent it?

[ajdelange]

Bitterness usually declines (if slowly) over time. I'd guess you are perceiving the sharpness that CO2 imposes (which is one of he reasons we use it) so I'd suggest lowering the dispense pressure a couple of psig and bleeding the kegs every couple of days until equilibrium is reached at the new pressure.

[PhillyBrewer]

Thanks. I'll try that. I have it at like 9 PSI.

[Hoser]

What is your kegerator set at? If it is set to low the beer could be freezing and concentrating your beer which could lead to an increase in bitterness.

[Steelers&Beer]

once the beer is carbonated and serving pressure is set, turn the gas off. it's a little bit of a PIA but turn it on when serving and turn it off when you are done for the night.

[thatguy314]

I find when the beer is green and has suspended particles it softens all the flavors. When it drops clear every flavor is more pronounced. When it's clear, malt is sweeter and richer, bitterness is crisper and more assertive. This is of course also somewhat concentration dependent. In any event

[BDawg]

I've seen both the Carbonic acid from over-Carbonation as AJ points out as well all of the "brightening" effects that ThatGuy points out.
9psi takes some damn cold temps to over carb an IPA, though. What is the kegerator set at? I've always liked 2.4 volumes, 11 psi at 40F for my medium carbonated beers. See http://www.kegerators.com/carbonation-table.php for help with this.

Other things to consider include backing down the IBUs (HERESY!!!), changing to lower cohumulone hops for bittering, and maybe just throwing it into a brite tank with a cold crash before kegging. All of these 3 will require re-dialing in the recipe once you go with them, but that seems to be the intent here, no?

HTH-

Oh, thought of one other thing.... Gotta ask, are you sure it is limited to simply increased percieved bitterness? Is it possible that this is sanitation related? Counter fill a bottle when the issue happens. Put it aside at room temp and leave it alone for a couple weeks. chill back down to serving temps and see if there is a pronounced infection.

[PhillyBrewer]

Not sure the exact temp, but it's not that cool. have it set at like 3.5 out of 5 on the dial thermostat for whatever that's worth. I'd imagine it's in the low 40s.

I'll try turned the CO2 off after I force carb until I need a little more to push the beer out.

It's been the case with every beer that I can recall with any sort of hop presence with the only possible exception being a 50/50 wheat/2-row beer I made that used Citra exclusively (great beer btw!). I assume the wheat and possibly the Citra kept things smooth.