Hops: Removal at Flame-out Vs. leaving in

[shenngeo]

I have been working in BeerSmith for about 3-4 years now. It has really helped my recipes! I struggle to understand the relation between bitterness, flavor and aroma as it pertains to hop addition times. I have tried countless variations to increase aroma with little success. Lately I have been skipping the 60-minute additions in favor of 20, 10, 5 and flame-out additions. This has yielded great results. It has brought down the IBU, and the flavor/aroma has gotten much better. My question is; When it comes to whirlpool and flame-out additions, how do I correctly represent that time in BeerSmith? It seems that the longer the time, the more the bitterness goes up. At flame-out I use an emersion chiller. It takes me about 15 minutes (once set up,) to bring my wort down to the 70° range. (Maybe 20-25 minutes with set-up.) Should I be counting the total time with set-up, or is there a point (temperature-wise,) where the hops will stop adding bitterness? Thanks!

 

[patpawlowski]

Apparently, isomerization drops pretty dramatically under 185ºF (85ºC), which I would expect would be achieved pretty quickly.

I'm curious why it would take so long to set up your immersion chiller. I drop mine in the boil 15 minutes before flame out to sanitize it and have it connected up and ready to go at flame out. It takes me 15 minutes to get below 100º F, but I haven't paid much attention to how long it takes to get down to 185º.

 

[BrewCat]

Well is it a 5 gallon batch. From 212 to 70 in 15 with only an immersion chiller is impressive, to me anyway . According to the online calculator I use once the wort is below 180 they not adding bitterness. This is the temperature I'll add my whirlpool addition. The flame out hops will still show adding bitterness but will stop as the wort is cooling. Its probably negligible though. I don't know the science of it but that's my understanding anyway