HELP: All hoppy beers develop same flavor

[rab53]

To preface, I have been brewing for 10+ years the last 2 on my current system. In the past year, I have made 6 hoppy beers, IPA/DIPA/Pale Ale/IPL. Each developed the exact same aroma shortly after kegging. The smell is what I can describe as 'overripe fruit', like maybe an old squishy apple (but not fresh green apple). Flavor gets dull and a bit sweet. Bitterness goes away, even the Pliny clone DIPA. Color stays consistent, no perceived darkening even on the palest beers.

Process for every beer involves building water from RO. I have used high sulfate profiles (300 ppm) for most of these beers, but lower (75 pmm) on last batch to try and rule that out as a cause.
Mash pH ranged from 5.4-5.6 room temp. This is my next target for testing, trying for lower target.
Fermentation is done in conical with spunding valve. I usually leave it at 0 psi until fermentation is finished then increase pressure, but have set it to 5 psi near tail end as well.
Dry hops are added through lid via CO2-purgeable sight glass apparatus. Sometimes during active fermentation, sometimes after.
Fermentation temperature is tightly controlled with glycol/heat wrap.
No issues ever reaching final gravity. Beer is cold crashed and trub/hops are dumped within 2 weeks. Gravity samples taste good to great.
Kegs are filled with sanitizer and purged with CO2. Line gets hooked up from TC valve to out post on keg. Hose is purged with beer and keg is filled under CO2 pressure.
Keg goes into lager fridge and carbed once chilled.
I use the same process for all my beers, but only have issues with the hoppy styles. German lagers, Belgian ales, stouts, etc are fine.

I anticipate the first answer to be 'oxidation'. If so, I am at a loss on how to improve my process. I will also not that the beers are 'crisper' if I add a drop or two of phosphoric acid to the glass prior to pouring, though this could be with any beer. The off aroma also dissipates when I swirl the glass to off-gas, but flavor is still dull.
In review of notes, I used US-05 for 5 of 6 batches and W-34/70 for the other. Ferm temps on the former batches were done on both low and high ends of range.
The only true constant I can see is dry-hopping and dry yeast, though I have made other styles using dry yeast without issue.

Sages of HBT, please lend your expertise. Thanks!

 

[bkboiler]

Hmm ...that's an interesting flavor...so you taste the beer prior to putting it in the keg and it's not there while it's in the fermenter?

 

[rab53]

Hmm ...that's an interesting flavor...so you taste the beer prior to putting it in the keg and it's not there while it's in the fermenter?

Correct, gravity samples are distinctly different from kegged beer. For example, I just tapped a Nectaron Pale SMaSH on Monday. First pints were muddy from sediment then clear. Taste was underwhelming (recipe imo) but that smell was absent. This was my first time using a lower sulfate level and I had my hopes up. Sure enough by day 2 it crept in, and now on day 4 it's a one note beer.

 

[day_trippr]

Well, you knew it was coming but the symptoms - aside from the lack of color change which is actually one of the last stages of hoppy beer death - sure sounds like oxidation taking its toll. And oxidation seeks out hoppy beers with a vengeance, so...

That said, the only process step I'm wondering about wrt to the whole character loss paradigm is the cold crashing. There's no note regarding exogenous CO2 provision to an otherwise sealed fermentor during that stage to avoid O2 take-up, and I can say from experience that it matters when dealing with highly post-boil hopped brews.

You may actually have it covered and just didn't spell it out, but as you're asking, that's the one thing missing from an otherwise apparently solid process...

Cheers!

 

[rab53]

Well, you knew it was coming but the symptoms - aside from the lack of color change which is actually one of the last stages of hoppy beer death - sure sounds like oxidation taking its toll. And oxidation seeks out hoppy beers with a vengeance, so...

That said, the only process step I'm wondering about wrt to the whole character loss paradigm is the cold crashing. There's no note regarding exogenous CO2 provision to an otherwise sealed fermentor during that stage to avoid O2 take-up, and I can say from experience that it matters when dealing with highly post-boil hopped brews.

You may actually have it covered and just didn't spell it out, but as you're asking, that's the one thing missing from an otherwise apparently solid process...

Cheers!

Oxidation sure does seem like the culprit, right? It's a head-scratcher for me since I've done pale lagers that have been stored 6-12 months that are just fine, no variance in process.
But to answer your question, I add CO2 to at least 5psi in the conical prior to cold crashing using a Spike all-in-one PRV.
Maybe I'll look into using anti-oxidants during packaging.

 

[day_trippr]

fwiw, I've been dissolving one teaspoon of ascorbic acid in 30ml of warm water and injecting it into each purged keg and believe it really does extend the shelf life of my neipas. In this post-Covid stay-home world where I'm not getting as much help kicking kegs I've had them go 6 months and still be awesome and "bright" (for an neipa "bright" ).

I wouldn't keg without it now...

Cheers!

 

[doug293cz]

Oxidation sure does seem like the culprit, right? It's a head-scratcher for me since I've done pale lagers that have been stored 6-12 months that are just fine, no variance in process.
But to answer your question, I add CO2 to at least 5psi in the conical prior to cold crashing using a Spike all-in-one PRV.
Maybe I'll look into using anti-oxidants during packaging.

When you add the CO2 to the conical, do you leave it connected at 5 psi, or do you pressurize and disconnect? How long do you typically cold crash for?

Brew on

 

[rab53]

When you add the CO2 to the conical, do you leave it connected at 5 psi, or do you pressurize and disconnect? How long do you typically cold crash for?

Brew on

I pressurize and disconnect. Sometimes it will stay above zero, sometimes I'll need to reapply gas. There is always sanitizer in the airlock which seems to stay consistent. The PRV isn't like a standard airlock, so if there were suck back, the fluid level should drop. Keeping low level positive pressure is something I will try.
Cold crash at least 12-24 hrs.

 

[Bobby_M]

I vote for acetaldehyde. The process seems pretty solid for oxidation and the lack of color change is somewhat supportive. Describe your yeast selections and how you figure out pitch rate, if at all.

 

[rab53]

I vote for acetaldehyde. The process seems pretty solid for oxidation and the lack of color change is somewhat supportive. Describe your yeast selections and how you figure out pitch rate, if at all.

For the six beers in question, I used US-05 for five of them. Two to three sachets depending on gravity. The sixth beer used three sachets of W-34/70.

 

[Bobby_M]

That's for a 5 gallon batch?

 

[JAReeves]

1 sachet of S-05 for 5G of <=7% beer seems appropriate. Higher than that, I would do a starter or multiple sachets. Anyone want to chime in on if this would affect the final flavor of the beer?

 

[Bobby_M]

A 5.5 gallon, 1.060 calls for two packs if not rehydrating. Once you jump up above 1.060 the recommended pitch "rate" also goes up so 5.5 gallons of 1.070 goes up to 3 packs if not rehydrating.