[hopfenundmalz]

The essential oils can combine to form the flavor compounds.  The essential oils are in the beer if you dry hop.  I have aded hops at 180F to keep some in the beer, or let it combine.
Flash points for the essential oils.
Caryophyllene=200F
Humulene=110F
Myrcene=103F
Farnesene=79F
I think you see which aroma oils ones are had by dry hopping.

I'm not sure I understand, are you saying that hops high in low temp flash points of essential oils make good candidates for dry hopping? I see some of my favorites on the Hopunion data page are high in Farnesene:
Amarillo 2-4%
Cascade 4-8%
Saaz (US) 9-13%
Sterling 11-17%
Some I don't like for dry hop, but do like for late or whirlpool hopping are low in Farnesene:
Chinook <1%
Columbus <1%
Hallertau <1%
Simcoe <1%
[/quote]
It has to do with the flash points.  That big blast of aroma you get when putting a charge of hops into the boil - that are the oils leaving the beer.  Some get disolved and turn into flavor compunds.  Dry hopping at roon temperature allow those with the lower flash point to disolve into the beer, rather than being driven off.
Farensene=floral.  Myrcene = citrus and fruity.  Humulene=spicy and dank.

[denny]

That's what I was getting at.  I've done a couple batches with nothing but FWH.  I perceived hop flavor, but I didn't perceive aroma.  According to what you said about tasting, there must have been aroma there, but I didn't perceive it separately from flavor.  In my blind tasting, I noted no hop aroma whatsoever.

[Kaiser]

Based on a presentation at the last NHC, there is a good chance that commercial hop drying drives of most of the Farnesene.

Kai

[hopfenundmalz]

Based on a presentation at the last NHC, there is a good chance that commercial hop drying drives of most of the Farnesene.

Kai

You are correct.  Unless you grow and dry your own.   

[tschmidlin]

How is it possible to have hop flavor without aroma?

Specifically what other than bittering compounds sensed by the tongue and retronasal perception of volatile aromatic compounds contributes to hop "flavor"?

1st wort does add flavor, no aroma,

To reiterate, unless current scientific understand of how flavor is perceived is wrong, this is impossible. The "flavor" of hops is a combination of the bitterness, sensed by the tongue, and the aroma sensed retronasally. If there is no aroma, the flavor is simply "bitter".

Impossible is a dangerous word

It is possible to have perceived flavor and no aroma if the volatilization temperature of the compound is higher than the beer temp and lower than your mouth temp.  As the beer warms in your mouth it will release different compounds and more of some that may push it above the level where it can be detected.  If that's the case though, I'm not sure why it wouldn't be driven off by boiling your FWH.

It is also possible that a reaction with the chemical environment in your mouth releases some aromatic compound and gives you a perceived flavor but no aroma from the glass.

I'm not saying it is either of these things, but they are possible explanations.

[chaz]

Here's some excerpts from Mike "Tasty" McDole's Facebook feed from earlier this month, I don't think he'd mind. I think he might even be looking for others to help experiment from the sounds of it:

Mike: Today I'm trying to unravel the mystery of hop utilization in the whirlpool. I could use some help.
I was thinking the challenge here is to develop a formula based on the alpha acid level, volume, temperature, and time. I could just make one batch of minimally hopped wort and whirlpool small amounts, collecting samples over 30 minute period for a given alpha at a given temperature. I'm looking for some help a brewery that has their own equipment for determining IBU levels.

Mitch Steele (Stone Brewing): 18% of our wort bitterness in Stone Ruination IPA comes from the whirlpool addition. I'll have to do the calculation to see what that is in terms of efficiency.

Mike: That's great info Mitch. That's what I'm looking for here. Matt says he gets 22%. (I'm assuming he's talking about Matt Brynildson/Firestone Walker)

Mitch: 18% is the percentage of total IBU's we get. We dump a lot of hops in the whirlpool, so I need to calculate the actual utilization. Our whirlpool is 15 minute fill, 15 minute rest and 45 minute KO-total 75 minutes
OK, I did the calc, it looks like 9.6% utilization with our hops that are added prior to filling the whirlpool, 75 minute residence time at ~200dF, added to 18dP wort.

Jim Matt: At Sun King, for our Osiris Pale Ale, (according to our magic spreadsheet) it looks like we are ~10% utilization for a 20 minute whirlpool and a 60 minute knockout, on a 30 BBL batch.

Colin Kaminski: Mitch, do you calculate the amount of IBUs stripped by the yeast and does that effect your pitching rates?

Mitch Steele: No we don't. We can measure IBU, so we measure wort IBU and beer IBU, and adjust hopping rates if beer IBU drifts. Of course, pitch rates need to be consistent! I tried to talk the A-B R&D dept. into doing a similar study, but couldn't get the proposal through, given that we weren't maximizing hop usage or brewing really high gravity beers. However, what I do know about this came from the work we did get done at A-B. I think Tom Shellhammer up in Oregon might be looking at this too.

[hopfenundmalz]

I would pay more attention to the utilization number than the % of total IBUs.  The ~10% utilization is good information.

Ruination has a big bittering charge at 60 minutes - at least in the BYO recipe that the Stone brewers provided.

FW UnionJack has fewer IBUs from the boil, but a huge charge into the whirlpool.  Listen to the FW episodes in the Brewing Network.

Pelican Pubs Kiwanda Cream ale has 100% of the IBUs from the whirlpool, as they add no hops to the boil per Darron Welch in BYO.

[pinnah]

Very cool information Chaz!  Thanks.


   

[chaz]

Pelican Pubs Kiwanda Cream ale has 100% of the IBUs from the whirlpool, as they add no hops to the boil per Darron Welch in BYO.

I just got this from one of the brewers:
Our procedure for Kiwanda is to add all the hops at boil stop, ramp down the kettle temp., whirlpool for about 3 mins., and then rest for about 30. Knock-outs take about 30 mins. We send all our beers to Analysis Labs here in Oregon, where IBU's are measured as low as 21, and as high as 29 consistently

I asked how many pounds per barrel they add and he replied:

11 pounds. We usually knock out 18-19 barrels.
----------
I'm thinking he meant 11 pounds total and not lb/bbl...? Because on a homebrew scale that'd be what, around 2 pounds in a 6 gal batch (?) which seems pretty crazy to me... where 11lb total would be close to 2 ounces?

[hopfenundmalz]

The homebrew recipes that I have seen for Kiwanda have 2 Oz of Mt Hood for 5 gallons.  Hope this helps.