[rbowers]

When doing a hop stand say for 30min at 180-190F (held constant by electric element) you will likely get some AA isomerization from the hop stand hops added after the boil- or at least that is my understanding/assumption.  Will you continue to get isomerization from your 60 min addition bittering hops and if so, how much?  Going to brew an APA with a 60 min addition, 30min hop stand at 180 or so, and dry hop.  Accounting for just the 60 min bitterring charge I assume about 23 IBUs (1oz of pacific jade 14.3%AA in a 12 gal batch).  The hop stand hops are going to contribute about 15IBUs assuming about 10% utilization (what I have read is best estimate).  Looking to get around 37-38 IBU total.  Is there a chance continued isomerization of 60min addition during the hop stand will push it much higher?  How much higher?

[denny]

Yes, just a bit....http://realbeer.com/hops/research.html

[Robert]

At 60 min you're pretty well maxed out on utilization, and getting to the point of degradation where you'll actually lose some bitterness from that addition.  Article in the latest Zymurgy touches on this.