I just put an all extract version of Jamil's Evil Twin into the fermentor this morning which uses all late hop additions for the bittering and aroma. I adjusted his all grain recipe with Beer Smith and went with half the extract at 60 min and the remainder at 30. As I was brewing, I began to think "why did the IBU's change in Beer Smith when the first Hop addition isn't until 10 minutes after the late addition of extract"? There is about a 5 IBU difference between the late addition or having all the extract at the beginning of the boil.
Does the extract require some time between the addition and when it effects the hop utilization? Or is this a miscalculation because normally the hops would be in for the full boil?
Does the extract require some time between the addition and when it effects the hop utilization? Or is this a miscalculation because normally the hops would be in for the full boil?