PicoBrew Z - Whirlpooling and Bitterness

[ListerH]

Has anyone has success whirlpooling on the Pico Z? I have done a couple of batches now and I suspect that the hops in the various compartments continue to isomerize while the water temperature drops to whirlpool temp.
I think the way the Z works is to drain the hop compartments and then circulate the water through the machine until cooled. But that means the hops are not cooling at the same rate. And as they are not completely dry, the acids continue to isomerize. So when the whirlpool water recirculates, it flushes those hop compartments and you get unintended bitterness? That is my theory.
I think even if you have your whirlpool hops in compartment 4 for example, the machine whirlpools all compartments... if that's the case, then it would support my theory.

Any thoughts?

 

[alestateyall]

Has anyone has success whirlpooling on the Pico Z? I have done a couple of batches now and I suspect that the hops in the various compartments continue to isomerize while the water temperature drops to whirlpool temp.
I think the way the Z works is to drain the hop compartments and then circulate the water through the machine until cooled. But that means the hops are not cooling at the same rate. And as they are not completely dry, the acids continue to isomerize. So when the whirlpool water recirculates, it flushes those hop compartments and you get unintended bitterness? That is my theory.
I think even if you have your whirlpool hops in compartment 4 for example, the machine whirlpools all compartments... if that's the case, then it would support my theory.

Any thoughts?

Most of the oils from previous hop additions should be in the wort not still in the hop pellets. At least, I would say that is the case for the older additions. More recent additions may not have been as thoroughly flushed.

I think that hop oils continue to isomerize below boiling temps. I am sure your right flushing containers 1-3 after they sit for a while adds some bitterness but I bet the isomerization you get from staying at a relatively high temp for the whirlpool duration is a much bigger contributor. You might minimize that effect by chilling faster and lowering your whirlpool temperature.

PS. I don’t whirlpool. I use 5 minute additions and then dry hop. Those two get me plenty of flavor and aroma. That said, I go more for APAs than Imperial IPAs.

 

[Craiginthecorn]

Very old thread, but I'll add my two cents anyway. In normal brewing practice, all of the hops would still be in the wort during whirlpooling, so the step filter cascading method isn't really any different in that regard. Yes, you will continue to extract additional bitterness, but at lower amounts per minute compared to boiling temperatures. Good brewing software will account for those IBUs in its calculations. Brewfather does and I believe that BeerSmith does as well.