[Alewyfe]

So, I'm brewing with a friend the other day. We both brewed the same recipe. We used some suspect malt that was given to us (I figured it was old as I came up short a few points whenever I used this stuff) Anyway, wort into the kettle and we were both 4 OG points low. I added some hot water and just sparged some more then boiled down the wort for about 45 minutes and got to my desired OG, then began my hops additions and timing my 60 min. boil. When I had finished boiling and started chilling, my friend was still boiling and I remarked about how I got ahead of him when he started first. He informed me that he was concentrating his wort to bring up the gravity. The thing is, he had already done all his hopping. Now, he did pull his hops before doing this boil, but my question is, what happens to all those late addition hops that were added for flavor and aroma? Obviously concentrating the wort is also going to concentrate the bitterness, but by continuing to boil, even after pulling the actual hops, wouldn't you continue to isomerize the hop oils even though the actual hops were not in there?
I haven't tasted the beer yet, it's still fermenting, but I'm expecting it to be pretty bitter.

[denny]

You don't get a lot of IBU past 60 min. so it may not be as bitter as you expect.  But I expect a good bit of hop flavor and aroma to be boiled out.  When I'm doing something similar, I check my gravity before starting my late additions.  If I'm on track, I go ahead with the 20 minute and less hops.  If I'm not near my OG, I hold off on those additions until I am.

[Alewyfe]

Yah, that's a better idea Denny, but my actual question is about the less than 60 minute hops. Do those leave oils that continue to isomerize and become bitter with the extended boil time, or is this not the case because that actual hop matter has been pulled?

I'm theorizing that those oils which contribute the aromas and flavors are still sitting in the wort and that the extended boil time would move them from there to a bittering  like addition. Probably not to the same extent as if the actual hops where still in contact, but surely some of those chemicals have gone into solution and will continue to be modified by extended boil time.

[denny]

Yah, that's a better idea Denny, but my actual question is about the less than 60 minute hops. Do those leave oils that continue to isomerize and become bitter with the extended boil time, or is this not the case because that actual hop matter has been pulled?

I'm theorizing that those oils which contribute the aromas and flavors are still sitting in the wort and that the extended boil time would move them from there to a bittering  like addition. Probably not to the same extent as if the actual hops where still in contact, but surely some of those chemicals have gone into solution and will continue to be modified by extended boil time.

As far as i know, Diane, you're correct.  The oils in the beer will continue to isomerize.  How much will depend on how long he boiled them....DUH!

[erockrph]

Yah, that's a better idea Denny, but my actual question is about the less than 60 minute hops. Do those leave oils that continue to isomerize and become bitter with the extended boil time, or is this not the case because that actual hop matter has been pulled?

I'm theorizing that those oils which contribute the aromas and flavors are still sitting in the wort and that the extended boil time would move them from there to a bittering  like addition. Probably not to the same extent as if the actual hops where still in contact, but surely some of those chemicals have gone into solution and will continue to be modified by extended boil time.

We're talking about 2 different things here. Any alpha acids in the wort will continue to isomerize, and the bitterness will increase as well. Any hop oils that would contribute to flavor and aroma will continue to be driven off by the boil.

In the end, I would expect more hop bitterness and less hop flavor and aroma.

[HoosierBrew]

I agree - likely more bitterness and less flavor /aromas.

[Alewyfe]

Thanks for weighing in guys. Kind of what I was thinking, but just wanted to see if my thinking was correct.