I'm confused about the concept of using an extended whirlpool time to get more hop aroma. My experience is limited, but it's the exact opposite: letting the hops sit in hot wort for a longer period of time may actually drive off hop aroma.
I learned about this as I was working with one commercial brewer to scale up a pro am batch I made last year. Since that brewer had never been a homebrewer, I talked to another commercial brewer who had recently made the switch from homebrewing to commercial. I asked how aroma hops should be scaled from a homebrew recipe to commercial. His advice was that the quantity of hops is proportionately the same, but the timing is different. He noted that on the commercial scale, your flameout addition sits longer at a higher temperature while the wort is whirlpooled, then while the wort is slowly drained through the plate and frame heat exchangerinto the fermenter. So, whereas a flameout addition may sit in hot wort for 10-20 minutes while the batch is cooled with an immersion chiller at the homebrew scale, it may sit for 45 minutes to an hour at high temperatures on a commercial scale. So, to match the aroma of flameout addition, he suggested moving the flameout 10 or 20 minutes into the whirlpool.
This made sense to me, but we did not do it. The brewer I was working with considered it, but was concerned that the remaining whirlpool time wouldn't be sufficient to allow the hops to settle into the center of the kettle. This would risk sucking hops into the plate and frame. So we did the addition at flameout. Result: less hop aroma than my homebrew batch.
I know this is a sample of only one. But the principle makes sense to me: heat drives off aroma. Does anyone feel they get more hop aroma from an extended whirlpool? Does it work better if you cool the wort first (i.e., with an immersion chiller, say to 100 F or so), then allow the hops to set for 45 minutes?