Just got a few # of hops. Galaxy is like 18.5 Vic Secret is 20+ and Citra was up there, too. How are you guys utilizing them in the boil without ending up with an overly bitter beer? Even whirlpool additions are going to cause problems.
Depends when you add them. Truthfully, I don't even pay attention to the AA% in my hops any more as there's not much isomerization going on at < 180F.
^^^ This. If you are going to use a bittering charge, a neutral, low-cohumulone varietal, like Magnum or Horizon is your best bet.
This will still affect IBUs. In fact, dry-hopping also affects IBUs. I just had analytics run on one of my beers which was heavily dry-hopped, and the IBU numbers came out as more than double the calculated IBUs from BeerSmith.
If you add all your hops during a hopstand or whirlpool (with none during the boil), isomerization is limited (at least greatly, if not completely) depending on the temperature that you add your hops and how long you hold your wort at that temperature.
Since isomerized alpha acids are not the only thing that contributes to IBUs or to the bitterness of the beer, yes, dry hopping can and does affect that calculation. It is, however, not as straight-forward as it might seem, as Scott Janish details here.
Recently, I overheard a pro-brewer talking about how Chinook AA has dropped over-all in recent years, as well as becoming less piney and more fruity. So it may just be a result of plants maturing, with certain genetics going one way or the other.
Let's not forget that hops are an agricultural product that is significantly influenced by the weather throughout the growing season. Some well timed rain and hot sunny weather can result in some fantastic hops. Also, hops left on the bine for a bit longer will increase in AA. So if weather delayed harvesting that could effect the AA as well.
