[roguejim]

Just recently I've been having some problems with hop astringency in my IPAs. At first I thought it was the Columbus hops themselves, but now I'm thinking it's more of an issue of hop quantity rather than variety. I Googled "hop astringency" and came across a Q and A from BYO's Dear Mr. Wizard.
http://www.byo.com/stories/wizard/article/section/121-mr-wizard/1129-mash-temperatures-a-hop-astringency-mr-wizard

The Wizard's answer included the statements below:
"Hops contain bittering acids, aromatic oils and plant matter. It is the plant matter that imparts this potentially unpleasant flavor. If the quantity of plant matter added to the beer is reduced, so is the astringency in the finished product."

So, my question is how some guys are brewing "hop bomb IPAs", but with little or no astringency? The hop quantities are huge.

[mabrungard]

Kettle pH is an important factor for reducing tannin extraction and harshness. 5.4 is about as high as you want the overall kettle pH to be. But, there is a lower limit for kettle pH where the finished beer will be tart and hop expression will be reduced. That hop expression issue was just reported by Colin Kaminski yesterday at the NHC in Seattle. I have the feeling that the lower ph limit is subjective, but its probably not lower than about 5.1.