[HoosierBrew]

This is pretty interesting stuff, from Stan H's site:


http://appellationbeer.com/blog/why-dry-hopping-may-lower-iso-alpha-acids-but-boost-bitterness/

[denny]

Well, it just so happens that Drew and I will be discussing that on the podcast we're gonna record in 10 minutes!

[denny]

Here's the other thing about it...http://scottjanish.com/increasing-bitterness-dry-hopping/

[HoosierBrew]

Pretty good timing then, Denny.   That's cool to see Scott put the info into practice, and test out IBUs as well. Good info all around.

[erockrph]

So dry-hopping increases humulinone and decreases iso-AA concentrations. Humulinones are less bitter than iso-AA's on a per-concentration basis, and have been reported to leave a smoother bitterness. That makes me wonder if beers that are dry-hopped at a massive rate would have a noticeably smoother bitterness than one with a lighter dry hop.

This also has me wondering if more humulinone survives from whirlpool additions than typical boil additions, and if this factors into why there appears to be a smoother bitterness (in my experience at least) from whirlpool IBU's compared to boil IBU's. That's just conjecture and speculation on my part. Man, I wish I had my own HPLC...

[HoosierBrew]

So dry-hopping increases humulinone and decreases iso-AA concentrations. Humulinones are less bitter than iso-AA's on a per-concentration basis, and have been reported to leave a smoother bitterness. That makes me wonder if beers that are dry-hopped at a massive rate would have a noticeably smoother bitterness than one with a lighter dry hop.

This also has me wondering if more humulinone survives from whirlpool additions than typical boil additions, and if this factors into why there appears to be a smoother bitterness (in my experience at least) from whirlpool IBU's compared to boil IBU's. That's just conjecture and speculation on my part. Man, I wish I had my own HPLC...

Yeah, that was my takeaway from the whole thing, too. The IPA that I sent you (albeit slightly undercarbed) had a ton of theoretical IBUs , 70 up front from Columbus but with a ton in the whirlpool and dry ( 12 oz whirlpool and 5 oz dry IIRC). To me it seemed to have a pretty smooth overall bitterness, more than it should.

[erockrph]

Yeah, that was my takeaway from the whole thing, too. The IPA that I sent you (albeit slightly undercarbed) had a ton of theoretical IBUs , 70 up front from Columbus but with a ton in the whirlpool and dry ( 12 oz whirlpool and 5 oz dry IIRC). To me it seemed to have a pretty smooth overall bitterness, more than it should.

The IPA I had measured in a lab came back at 98 IBU measured, but it was only whirlpool and dry hops. It was way, way smoother than a 98 IBU beer should be.

[brewinhard]

Yeah, that was my takeaway from the whole thing, too. The IPA that I sent you (albeit slightly undercarbed) had a ton of theoretical IBUs , 70 up front from Columbus but with a ton in the whirlpool and dry ( 12 oz whirlpool and 5 oz dry IIRC). To me it seemed to have a pretty smooth overall bitterness, more than it should.

The IPA I had measured in a lab came back at 98 IBU measured, but it was only whirlpool and dry hops. It was way, way smoother than a 98 IBU beer should be.

Wow!  Whirlpool and dry hops to 98 IBUS? Do you remember temp and time for the whirpool, and amounts to get you there? 

[zwiller]

So pretty much all brewing rules are out the windows these days...     I have an IPA totally overbitter from the dry hop and no, it ain't polyphenols. 

[erockrph]

Yeah, that was my takeaway from the whole thing, too. The IPA that I sent you (albeit slightly undercarbed) had a ton of theoretical IBUs , 70 up front from Columbus but with a ton in the whirlpool and dry ( 12 oz whirlpool and 5 oz dry IIRC). To me it seemed to have a pretty smooth overall bitterness, more than it should.

The IPA I had measured in a lab came back at 98 IBU measured, but it was only whirlpool and dry hops. It was way, way smoother than a 98 IBU beer should be.

Wow!  Whirlpool and dry hops to 98 IBUS? Do you remember temp and time for the whirpool, and amounts to get you there?

The calculated IBU's are just a garbage estimate based on Brewer's Friend's "No Chill" option that essentially just extends the boil by the specified. This was a 90-minute whirlpool at flameout, without any pre-chilling. The temp was about 180F at the end, IIRC. Total of 10.5 oz in the whirlpool and 6.5 oz in the dry hop for a 3-gallon batch. (Recipe calls for 3.5 gallons, but 10.5 oz of hops absorbs quite a bit of wort)

Title: House IPA

Brew Method: BIAB
Style Name: American IPA
Boil Time: 60 min
Batch Size: 3.5 gallons (fermentor volume)
Boil Size: 4 gallons
Boil Gravity: 1.058
Efficiency: 70% (brew house)
No Chill: 30 minute extended hop boil time


STATS:
Original Gravity: 1.066
IBU (tinseth): 475.51
SRM (morey): 7.62

FERMENTABLES:
6.5 lb - American - Pale 2-Row (72.2%)
2 lb - German - Munich Light (22.2%)
8 oz - American - Victory (5.6%)

HOPS:
2 oz - Citra, Type: Leaf/Whole, AA: 14.8, Use: Boil for 0 min, IBU: 104.49
2 oz - Apollo, Type: Pellet, AA: 18, Use: Boil for 0 min, IBU: 139.79
2 oz - Meridian, Type: Pellet, AA: 6.7, Use: Boil for 0 min, IBU: 52.03
2 oz - Motueka, Type: Pellet, AA: 7.2, Use: Boil for 0 min, IBU: 55.92
2.5 oz - Nelson Sauvin, Type: Pellet, AA: 12.7, Use: Boil for 0 min, IBU: 123.29
1.5 oz - Citra, Type: Leaf/Whole, AA: 14.8, Use: Dry Hop for 7 days
2 oz - Meridian, Type: Pellet, AA: 6.7, Use: Dry Hop for 7 days
2 oz - Motueka, Type: Leaf/Whole, AA: 7.2, Use: Dry Hop for 7 days
1 oz - Nelson Sauvin, Type: Pellet, AA: 12.7, Use: Dry Hop for 7 days

MASH GUIDELINES:
1) Infusion, Temp: 153 F, Time: 60 min, Amount: 18 qt, Sacc Rest

YEAST:
Fermentis / Safale - American Ale Yeast US-05

NOTES:
90 minute hop stand at flameout

IBU estimated as a 30-minute addition.

[erockrph]

FYI - Stan was on this week's BeerSmith podcast and touched on this, as well as a whole slew of other hop-related topics.

The other piece of the article (regarding dry hops increasing beer pH), has me wondering if it might be worth adding back some phosphoric acid in the keg to balance that pH effect. I'm not so much worried about the bitterness .It sounds like you're looking at 2-5 IBU difference from the pH change - just barely threshold. I just  wonder if the pH bump from dry-hopping has any other flavor impacts.

[blair.streit]

The other piece of the article (regarding dry hops increasing beer pH), has me wondering if it might be worth adding back some phosphoric acid in the keg to balance that pH effect. I'm not so much worried about the bitterness .It sounds like you're looking at 2-5 IBU difference from the pH change - just barely threshold. I just  wonder if the pH bump from dry-hopping has any other flavor impacts.

I always figure the bit of residual StarSan and associated foam takes care of that for me ;-)