So. I did a batch of brown ale which I bottled 4 weeks ago. My next batch was an IPA which I bottled 1 week ago. The brown ale was not really drinkable until last week which was 3 weeks after bottling. It was carbed fine after one week just not good. Now its excellent. The IPA.... Awesome after only 1 week in the bottle. Whats the reason for this? The only thing I can think of is the darker malts need more time to condition.
My guess would be that the hops in your IPA overpower the young/green flavors and aromas that decrease with additional time in the bottle.