Off Flavor - Oxidation?

[NHMikeT]

interesting to see how common this problem is...

grathan –
sorry for the delay but in response to your post on 11/5/13 I wanted to wait until I’d sampled a bottle of my latest batch before responding. Unfortunately, since this batch wasn’t kegged, it won’t address your issues with kegging, but I’ll briefly tell you how I’ve been kegging just for another data point:

I’ll usually move the carboy to the countertop before starting anything else in the process, so that anything kicked up will have time to settle some. After Starsanning the keg and parts, and reassembling, I run starsan through the keg and picnic tap to sanitize everything, (some people think this is a waste of CO2, but to me it’s worth it to purge the keg and lines). Then I purge the lines of the autosiphon, and rack to the keg with the lid open and covered by sanitized foil (you should see the CO2 “cloud” in the keg). I’m hoping to eventually start racking through the liquid out post to completely get rid of air contact…

Once full, I seal it up, and purge the headspace four times. Then I set the pressure between 8-12 psi depending on the beer and put it in the kegerator. FWIW, I usually don’t start drinking it 10days or more on gas. I do not do the “boost carb” method, but many people do so I’d be surprised if that process alone was enhancing oxidation more quickly for you. I’d guess the oxidation you’re having is from using oxidized hops, or something in your transfer methods. I can’t say I’ve solved this problem either as my hoppy beers haven’t turned out well lately.

My latest IPA was bottled because I’m about to move and have to break down my kegerator this weekend. First off, here’s the recipe (I was basically cleaning out the freezer and fermentables):
12# Rahr 2-row
2.5# Breiss Golden Light DME
11oz dextrose
8oz Crystal 40L
2oz Pale Chocolate (200L)

4oz Simcoe
3oz Centennial
2oz Citra
2oz CTZ
0.75oz Chinook
(all pellets)

2 packs rehydrated US-05
1 whirlfloc
1/2tsp Wyeast nutrient

RO water
4 g each gypsum and CaCl2 in mash
4 g gypsum in kettle

HOP schedule:
Centennial, Chinook, Simcoe @ FWH
Centennial @ 30
Chinook, Citra, Simcoe @ 15
Citra, Simcoe, Centennial @ KO
Centennial, Simcoe, Citra, CTZ @ Dry Hop for 3 days only (5+ oz)

Process:

Mashed at 151F, 1.3 qt/lb ratio for 70 minutes. Mashout 10 mi settled to about 165F. FWH added to first runnings. 15 minute batch sparge at 164F, collected approximately 6.5 gallons, topped up to 7 gallons with RO water (in hindsight this was not enough pre-boil volume given the amount of hops).

Boil as usual, chilled to 63F, oxygenated for 90 seconds with pure O2 and 0.2 micron stone on as low a setting as allows bubbles to appear. Pitched rehydrated yeast. Fermented at 63-65F in swamp cooler. The yeast went to town on this batch, blowing off for 3 days after starting fermentation within 8 hours. After 5 days, carboy removed from swamp cooler and raised to 68-70F, fermentation complete in 8 days (1.074 to 1.011). on 12th day racked to secondary on top of dry hops (autosiphon hoses and carboy both purged with CO2 as best I could). Dry-hopped at 68F and then put in cold closet for 24 hours (this only dropped temp to about 50F, which was enough to drop the hops out). Bottled on day 17.

I’m drinking the first bottle of this stuff now, after putting in the fridge two days ago and I must say, it’s undoubtedly the best hoppy beer I’ve ever made. At first pour the hop aroma is explosive and resinous, though not nearly as fruity as the gravity samples were, which is definitely disappointing. When I tasted the gravity samples from this beer I thought it was going to be one of the best beers I’ve ever had, but it’s just a really good hoppy beer (not on par with my commercial favorites). I get a slight hint of alcohol in the aroma and flavor after a few minutes in the glass (I think, at least) and also some slight vegetal-ness in the aroma too (*disclaimer: This is only my 23rd batch, so I’m not an expert at describing the subtleties by any means).

One thing I noted while dry-hopping was that the first two days, the smells from the airlock were unbelievable, and then on the third day they turned somewhat dull and muted (maybe more veggie and grassy?), so that’s when I decided to move the carboy. Next time I brew an IPA I think I’m only going to dry-hop for 24-48 hours with pellets, then keg-hop with leaf/cone hops. I should note that almost all these hops were freshly opened 2oz packs, except a little of the Centennial and the Chinook.

That’s all I’ve got to add at this point…. I’m hoping that this DIPA I have doesn’t go south. Let us know how your next one turns out and what you changed.

 

[knucklenitz]

This has been an informative thread. Same issue here with a Heady clone. Absolutely awesome for the first week but now very dull. I've had similar issues with previous IPAs but good success with other brews. No secondary, dry hop in keg, purge when transfer.

The high kegging pressure is an interesting thought, along with the old hops. I don't know what the age of my hops were but I did dry hop in the keg in a sack with pellet. Very murky, but again, the first week was one of the best beers I've brewed. Could it be residual hop matter interacting with suspended yeast? Not sure what the relationship is over time, but I've read there is a concern. It seems all the great hoppy/aromatic brews are pretty clear. Could filtering help?

More co-miserating than anything else. I wish I had the time to do all the test brews that tagz does!

 

[tagz]

This has been an informative thread. Same issue here with a Heady clone. Absolutely awesome for the first week but now very dull. I've had similar issues with previous IPAs but good success with other brews. No secondary, dry hop in keg, purge when transfer.

The high kegging pressure is an interesting thought, along with the old hops. I don't know what the age of my hops were but I did dry hop in the keg in a sack with pellet. Very murky, but again, the first week was one of the best beers I've brewed. Could it be residual hop matter interacting with suspended yeast? Not sure what the relationship is over time, but I've read there is a concern. It seems all the great hoppy/aromatic brews are pretty clear. Could filtering help?

More co-miserating than anything else. I wish I had the time to do all the test brews that tagz does!

A dull profile makes me think of pH. Do you adjust your water at all?

 

[knucklenitz]

A dull profile makes me think of pH. Do you adjust your water at all?

I bought the additives and have only adjusted once some time back. For the past few brews, no, including the Heady clone that was awesome for a week, then pooped out.

Although one example isn't enough data, I did an extract Black IPA prior to the Heady and had similar results. I should note also that I've have great beers l previously but a real test would be to do a control batch (with water adjustment) to make sure a non - IPA or another IPA has no issues still. The Heady clone is to expensive to test with.

 

[tagz]

If you can find your water report, you can punch it into the Bru'n water spreadsheet and get a reasonable idea of your pH. I used a pH meter in combination with the spreadsheet for a while and found it to be pretty accurate. High pH can cause dull hop flavors. A measured dose of lactic acid might brighten things up and make the flavors a little more crisp.

 

[knucklenitz]

If you can find your water report, you can punch it into the Bru'n water spreadsheet and get a reasonable idea of your pH. I used a pH meter in combination with the spreadsheet for a while and found it to be pretty accurate. High pH can cause dull hop flavors. A measured dose of lactic acid might brighten things up and make the flavors a little more crisp.

Thanks tagz. Will give it a shot.

 

[Wesjmc]

Since my last post, all my hoppy beers have had varying degrees of this off flavor. I have also ruled out oxidation. Most recently I even transferred from my fermentor to the beer-in post on my purged keg, essentially getting as close to a "closed" transfer as possible from a glass carboy. I was talking with the head brewer at a local brewery about it, and he said it sounds surprisingly like diacetyl. He used the word "surprisingly" because the off flavor wasn't the trademark "buttery" taste, but my process, ingredients, and timeline of this off flavor all point to diacetyl.

First, I have been using WLP002 (same as Wyeast 1068 that tagz has been using) at a low temp to keep the esters low (pitch at 63F and rise to 68F). On White Labs site they have data from forced fermentations of some of their most popular yeasts, and this strain produces more diacetyl than any other British or American strain that I could see.

Second, in my experience this yeast ferments crazy fast (2-4 days) and then drops like a brick. I always liked this as I got very clear beer, however, it may have been flocculating before cleaning up the diacetyl. At day 5 my carboy is brilliantly clear.

Finally, the precursor to diacetyl, acetolactate, is completely flavorless. It can exist in my beers at the time I rack from fermentor to keg without any off flavor. When it undergoes an oxidation chemical reaction, the acetolactate is converted to diacetyl, and the off-flavor emerges. This sounds like it is happening at the same 2-3 week timeframe as my beer is carbonating. This explains the flavor transformation in the keg. Check out this article: http://www.whitelabs.com/files/Diacetyl_Time_Line.pdf

Low levels of diacetyl don't always present themselves as the classic butter-bomb. This could be the exact off-flavor some of us are having that seems to dull the hop profile of our beers. I feel this off flavor has probably existed in my porters and other dark beers, but my palate simply doesn't pick up on it in any of my beers aside from my light, hoppy beers.

I currently have a batch fermenting away with WLP001. I will post back in a month or so when it's finished.

Cheers!

 

[grathan]

I don't think Diacetyl because it is always IPA. Something more to do with chemical reactions with Co2 and polyphenols dropping and oxidized high beta acid hops.

I had back to back successful ipas at the end of last brewing season. I took Tagz advice and used a single hop for all the additions. Limited dry hops to 2oz and added them while the yeast were still active. ALso used only freshly opened packages of hops. Also stopped oxygenating with pure o2 and removed cold-crash/gelatin from process.

 

[tagz]

I don't think Diacetyl because it is always IPA. Something more to do with chemical reactions with Co2 and polyphenols dropping and oxidized high beta acid hops.

I had back to back successful ipas at the end of last brewing season. I took Tagz advice and used a single hop for all the additions. Limited dry hops to 2oz and added them while the yeast were still active. ALso used only freshly opened packages of hops. Also stopped oxygenating with pure o2 and removed cold-crash/gelatin from process.

Good to hear you've made some progress! I've actually cranked my dryhop and flameout additions back up now that I've isolated some hops and proportions that work for me. I have a citra/simcoe/galaxy on tap that I'm really enjoying.

Wes - It's a good thought. I haven't heard about diacetyl showing itself as anything other than buttery flavors, but it's worth a test batch. Let us know how it works out. I recently switched back to 002 from Conan, because, like you, I love how quickly it ferments and drops clear. Plus, I got burnt out pretty quickly on the Conan profile.

 

[HossTheGreat]

I suspect oxygen is the culprit. I had been dealing with this issue as well in all of my dry hopped beers. Beers would be fantastic at first, but anywhere from a few days up to a couple of weeks after kegging, it would turn into what I can best describe as a caramel bomb that tasted very much like an old or oxidized beer. It would only show in dry hopped beers, all non dry hopped beers would remain nice, bright an clean. Here is what I did to eliminate oxygen exposure.

• Began adding first dry hop addition 3/4 way through fermentation
• No longer rack to secondary. Instead all dry hop additions are done in the primary.
• Flush carboy with C02 before and after each dry hop addition
• No longer cold crash in the carboy. If you listen to the most recent Session, Jamil states that cold crashing can introduce as much as 4% 02 into the beer.

In addition, I'm now going to experiment with a closed transfer from carboy to a purged keg, where I will do my dry hopping and, ultimately, cold crashing. From there, I will then transfer to a second keg for serving.

There was also a Sunday Session a few years back where Nate Smith and Tasty talked about Double IPAs. They stressed how absolutely important it is to reduce all oxygen exposure during the process as the addition of dry hops can add a considerable amount of O2 to the beer.

Regardless of how careful you are minimizing O2 exposure during your process, think about how much you are potentially introducing from the following:

• Transferring to secondary
• Multiple dry hop additions
• Cold crashing (O2 is drawn into your beer during this process)
• Transferring to keg

The main difference between a pro brewer's process and a home brewer's process is their ability to transfer everything in a closed system and reducing the amount of Oxygen. By really focusing on this aspect, I think you'll begin to eliminate this off-flavor completely.

Additionally, I would also stress to make sure all of your other processes are solid as well. Pitch a nice healthy pitch of yeast, properly oxygenate your wort prior to pitching, pay attention to your mash and kettle pH, be sure you're leaving your beer on the yeast long enough to clean itself up, and ensure you are making proper water adjustments to suit the style you are brewing.

 

[grathan]

Wow, great post. I'd like to learn more about closed system transfers. Lately I have doubts about simple flushing effectiveness. I'm gonna try another huge dry hop beer this summer.

 

[HossTheGreat]

Wow, great post. I'd like to learn more about closed system transfers. Lately I have doubts about simple flushing effectiveness. I'm gonna try another huge dry hop beer this summer.

Really not too complicated, here's the method I use to transfer from carboy to keg.

https://www.homebrewtalk.com/f35/carboy-keg-closed-system-37725/

Going from keg to keg is even easier. Just create a jumper line and attach to the liquid side on both kegs. Pressurize the keg you are transferring from and it will push the beer to the new keg.

 

[grathan]

Neat, is that what the pro brewers are doing then?

Maybe fashion some type of airlock bubbler to the gas out port. There was another thread that mentioned using a bathroom scale to measure level. I am thinking maybe let it overflow, then force a six pack out into bottles before force carbing.

 

[jbaysurfer]

Argh!! Well I kegged it up and it has that same stale flavor! I went back through my notes and the only other thing I can think of is old hops. I realized that one variety of hops I'm using is about 2 years old now. I bought a bunch of centennial and Columbus a while back and each batch has one of the two varieties in it. The last batch was Columbus and a fresher batch of Amarillo. Would it make sense that the Amarillo made the initial samples taste good but the oxidized hops took over? Can anyone tell me what oxidized hops taste like post fermentation? I know some hops smell cheesy when they get old but what do they do to a beer once it has been fermented?

Old hops sounds like what you're describing to me. I've had it too and switched my next batch to fresh, new hops and it was gone. I've also tasted it in several beers I've judged. People commonly think "DMS" when someone says "vegetal" but in hoppy beers, I've found it to be old hops more often then not.

 

[reuliss]

I suspect oxygen is the culprit. I had been dealing with this issue as well in all of my dry hopped beers. Beers would be fantastic at first, but anywhere from a few days up to a couple of weeks after kegging, it would turn into what I can best describe as a caramel bomb that tasted very much like an old or oxidized beer. It would only show in dry hopped beers, all non dry hopped beers would remain nice, bright an clean. Here is what I did to eliminate oxygen exposure.

• Began adding first dry hop addition 3/4 way through fermentation
• No longer rack to secondary. Instead all dry hop additions are done in the primary.
• Flush carboy with C02 before and after each dry hop addition
• No longer cold crash in the carboy. If you listen to the most recent Session, Jamil states that cold crashing can introduce as much as 4% 02 into the beer.

In addition, I'm now going to experiment with a closed transfer from carboy to a purged keg, where I will do my dry hopping and, ultimately, cold crashing. From there, I will then transfer to a second keg for serving.

There was also a Sunday Session a few years back where Nate Smith and Tasty talked about Double IPAs. They stressed how absolutely important it is to reduce all oxygen exposure during the process as the addition of dry hops can add a considerable amount of O2 to the beer.

Regardless of how careful you are minimizing O2 exposure during your process, think about how much you are potentially introducing from the following:

• Transferring to secondary
• Multiple dry hop additions
• Cold crashing (O2 is drawn into your beer during this process)
• Transferring to keg

The main difference between a pro brewer's process and a home brewer's process is their ability to transfer everything in a closed system and reducing the amount of Oxygen. By really focusing on this aspect, I think you'll begin to eliminate this off-flavor completely.

Additionally, I would also stress to make sure all of your other processes are solid as well. Pitch a nice healthy pitch of yeast, properly oxygenate your wort prior to pitching, pay attention to your mash and kettle pH, be sure you're leaving your beer on the yeast long enough to clean itself up, and ensure you are making proper water adjustments to suit the style you are brewing.

^ This! I've had the same problem as many of you and I too heard Jamil on the latest session. I've been cold crashing in my buckets and it's the only thing I think could be messing up my IPAs and APAs.

 

[mbbransc]

What if we only cold crash to ~50*F? I've heard that's sufficient to drop the yeast and should limit the amount of 'vacuum' from the pressure change. Would that limit some oxidation?

I'm currently fermenting in a 6.5gal bucket and racking to a 5gal bucket for dry hopping. Sounds like I should get at 5gal carboy to limit surface area. Or better yet, start kegging and flushing my system with CO2. That'll be my long term plan.

 

[grathan]

There was a post on HBA forms from Kai I think that showed the formula for figuring how much 02 gets sucked in, but I could never find it again after first seeing it.

Kegging is a good plan. crashing under co2 pressure would be ideal. Of course you could just serve out of the same keg so in essence, everyone cold crashes in the end anyways. Unless perhaps employing gelatin, which may clog dip tube with a gummy.

 

[slarkin712]

Finally, the precursor to diacetyl, acetolactate, is completely flavorless. It can exist in my beers at the time I rack from fermentor to keg without any off flavor. When it undergoes an oxidation chemical reaction, the acetolactate is converted to diacetyl, and the off-flavor emerges. This sounds like it is happening at the same 2-3 week timeframe as my beer is carbonating. This explains the flavor transformation in the keg. Check out this article: http://www.whitelabs.com/files/Diacetyl_Time_Line.pdf

Low levels of diacetyl don't always present themselves as the classic butter-bomb. This could be the exact off-flavor some of us are having that seems to dull the hop profile of our beers. I feel this off flavor has probably existed in my porters and other dark beers, but my palate simply doesn't pick up on it in any of my beers aside from my light, hoppy beers.

I've read something similar to this in a technical journal article and in my opinion this is what the problem that most people are reporting. I've been dealing with this off flavor problem for nearly a year and a half. I've been using the same grain bill and water profile with the same hop schedule varying the varieties of hops. I've used english, american and belgium yeasts. Fermented in buckets, glass carboys, and stainless conicals. dry hopped in primary and secondary. None of these things consistently eliminated the problem. I've probably made 15 IPAs in the last 1.5 years, and most of them have had this off flavor. 2 of them have been really great, with no noticeable off flavor, 2 have had just a hint of the off flavor, and the rest were just awful. I don't know what the genesis of these problems are, but with the steps I have gone to to avoid oxidation, and the steps i haven't gone to avoid oxidation and had good batches I am convinced the issue is an infection that causes the diacetyl issue.
I can't seem to pin the sanitation issue down. I use stainless fermentors, which can be aggressively cleaned with few places for infections to hide. Although they do use silicon gaskets, so perhaps things can live in there, but I clean them with PBW and then star san. I keep my fermentors completely closed until adding the dry hops. Even then I just add the hops through the airlock port, so there is very minimal oxygen exposure. And the batches have the off flavor when I go to keg them, so it's not in my kegging system. Nothing really touched the wort after the boil other than a silicon tube and camlock fitting on my kettle to drain into the fermentor. I run boil wort through that hose before chilling though. I do use an oxygen wand, so maybe I should bake that, but I usually just soak it in star san. I pitch the yeast(dry hydrated or from a starter) and then close the fermentor until adding the dry hops. I keep all IPAs fermenting between 64-68F with a fridge, thermowell, and temperature controller. Basically, there are not many places for an infection to take hold.
Near my wits end, I think I'm going to buy a microscope, staining solution, slides, etc. That should show something.
In the meantime, I've decided to dose my last 2 IPAs that had the off flavor with Brett B. That may remove the diacetyl, only time will tell. Will report back.

 

[grathan]

If it's only in IPA that you have an off-flavor, then you have to blame the hops, unless that is the only style that you brew. Hops can get oxidized in the pellet making process. Where do you buy your hops from?

 

[slarkin712]

I've gotten this flavor in a saison I dry hopped as well. None of my other beers get this off flavor. I get some of my hops from Label Peelers and some from Fresh Hops. I get them right after the harvest. Even gotten hops from my local supplier. The source hasn't mattered, and I don't have any hops older than 1.5 years old. Most of them are from this past harvest. I buy by the pound and use a vacuum sealer and bags to store unused hops in a freezer.
My guess is that whatever is causing the problem it only effects hop oils that haven't been isomerized, i.e. dry hops, or whirlpool hops.

 

[NHMikeT]

awesome that this thread is still going. I just brewed again after six-month hiatus due to a move and an IPA is dry-hopping in the keg now. I did a fully closed transfer from carboy to keg through the liquid out side. I'm hoping that this will solve the problem.

I do think that my problem with this flavor has been the hops, but we'll see in a couple weeks - I will report back. I mostly brew hoppy beers but this flavor has not been present in the few malt-forward beers I've made...I've definitely been paying much closer attention to the condition/aroma of the hops before using them (and unfortunately buying in smaller/fresh quantity since I don't own a vacuum sealer).

 

[BrixBrewco]

Any update on this? It's crazy that a lot of us our owning up to this. What's mind boggling is that a lot of is are creating great beers besides ipa's...it's my favorite style yet hardest to brew. I will note that I'm convinced it's the hops I'm buying...I will repost in a month to follow up


Sent from my iPhone using Home Brew

 

[homebrew_handyman]

Guys I'm having the same issue. After ten days I get a crushed aspirin flavor in mu IPA's. A buddy suggested it was because mu cleaner. I use oxy to clean but star san to sanitize. Any thoughts? I'll do tests this summer. IPA's are my favorite ber also.

 

[tagz]

Guys I'm having the same issue. After ten days I get a crushed aspirin flavor in mu IPA's. A buddy suggested it was because mu cleaner. I use oxy to clean but star san to sanitize. Any thoughts? I'll do tests this summer. IPA's are my favorite ber also.

Crushed aspirin sounds like astringency. Do you treat your water?

 

[homebrew_handyman]

Tagz I don't treat it at all. Get it from a drinking grade hose. How should I treat it? What should I be looking for? Are there tests I can do? Thanks

 

[Yooper]

Tagz I don't treat it at all. Get it from a drinking grade hose. How should I treat it? What should I be looking for? Are there tests I can do? Thanks

You can send a sample to Ward Lab and get a "household mineral test" for $26. That will give all you all need to know about your water.

It definitely sounds like a water chemistry issue with the flavor you describe.

 

[stewart194]

I'm dealing with some similar issues and am on a mission to figure this out. The hops in my IPA's just aren't as pronounced as they should be. The malt is bland as well and it seems to get worse within a week. The flat sample going into the keg tastes great, but then it all goes downhill. This isn't very obvious in my stouts and other beers...but I think they too get slightly "watered down" with time. I too have tasted the other things mentioned in this thread...slightly sour / green apple like, maybe a bit medicinal, etc. But it is super obvious in my Pale Ales and IPA's.

Like all of you, I'm getting really frustrated. IPA's are my favorite beer style. I'm extremely meticulous with my cleaning and sanitation, I've listened to all of the podcasts, searched the internet for hours and hours, etc, etc. Can't believe I finally stumbled onto this thread. It is exactly what I'm experiencing.

Here is what I've tried and ruled out...

1. Oxidized Hops - I recently made a Pale Ale with brand new vacuumed sealed hops from Hop Union, ordered from Northern Brewer. Did not make a difference.

2. Oxidation in general - I don't do a secondary and go straight from the fermentor to the keg. I started purging my kegs with CO2 and am VERY careful about not splashing the beer while racking to the keg. Didn't make a difference.

3. Water & Mash pH - I've been messing with my water constantly since I started brewing. I have an RO system in my kitchen so that is what I used. Then I learned that my city treats our water with Chloromines and that RO systems can't get rid of it, so I started using Campden tablets. I started using Gypsum and Calcium Chloride to create water profiles recommended by Tasty, Martin, AJ, etc, etc. I've tried adding the salts straight to the grain, then to all of the water before brewing, to the boil, etc, etc. I make sure my mash pH is between 5.2 and 5.4. I've treated the mash with Lactic Acid and also have treated the water before mashing in. None of this has seemed to make a difference as far as this problem is concerned. In fact my last Pale Ale was right at 5.4 without any addition of Lactic Acid, so it's not the Lactic Acid either.

I recently joined our local home brew club and was really surprised that almost NOBODY treats their water with Campden Tablets OR uses RO water. Most just run their tap water through a carbon filter and don't mess with it at all...and I've tasted some really nice beers of theirs, including IPA's. So I'm going to try this next.

4. Slight Infection - Here is where things get interesting. I've become overly crazy about sanitation thanks to this problem. But having a REALLY SLIGHT / MILD infection is one thing that's been in the back of my mind. I think it might be the ONLY thing that can zap the flavor of the amount of hops that I'm using in my IPA's. I also think if my stouts had this really slight infection that it would be hard to detect, but still there...which I think I've tasted. I think this might be why they are nice and rich and malty in the beginning, but lose that complexity over time.

I made a fresh batch of Star San a few weeks ago when I brewed Rye IPA. A few days ago I kegged a batch of Belgian Wit and just for fun I tested it with my pH meter and it was 4.4. Star San is supposed to only be effective if it is lower than 3.5. So I made a fresh batch of Star San and it was 4.2!! I talked to someone at Five Star and they said that Star San can lose it's effectiveness after 1 year! They said that I could try adding more Star San to compensate, but that I can't exceed 300 ppm or it will require a "rinse" before using. The limit is 1.5 oz for 5 gallons. There is no "expiration date" on the bottle, and I have never heard or read of anyone mentioning this. Not online or anywhere else. There are several posts about how long a "Mixed" batch of Star San will keep, but not the bottle of Star San itself. How many local home brew shops have bottles of Star San sitting on the shelves for over a year before they are purchased? So this really baffled me. I have never heard anything about it. Surely if this were happening to lots of people we would have heard about it? Not sure.

So that is where I'm at with this currently. I have also never ran a brush through the serving tube of my kegs. I just soak them in PBW for 20 minutes and run it through the lines, rinse with water, and run Star San through the lines before serving.

If I ever figure this out I will definitely report back.

 

[grathan]

Oxidation can also take form from of hot side aeration. BUt first let's look at Cold side aeration.


Look at this recent reprint of George Fix's work on Morebeer.

(1) Ethanol + oxygen (14,000 ppm)* acetaldehyde (25 ppm)

(2) Acetaldehyde + oxygen (25 ppm) acetic acid (175 ppm)

(3) Hop alpha-acids + oxygen (10 ppm) valeric and butyric acids (1–2 ppm)

(4) Hop oils + oxygen various oxygen-bearing compounds (9, 10)

(5) Unsaturated fatty acids from trub + oxygen oleic and linoleic acids (< 1 ppm)

http://morebeer.com/articles/oxidation_in_beer


Note that hop oils combined with oxygen create off-flavors and that alpha acids also create off flavors.







Now read this article from the industry's foremost dissolved oxygen tester.
http://tapintohach.com/2013/12/02/h...ide-affects-the-oxygen-concentration-of-beer/






My latest thoughts are that the co2 tank is ruining my ipas... which is pushing me to pressurized fermenting.

 

[mwjtennis]

Have you tried to steep / whirlpool the hops after the boil? Made a huge difference overall for me in the hoppy brews.

I'm dealing with some similar issues and am on a mission to figure this out. The hops in my IPA's just aren't as pronounced as they should be. The malt is bland as well and it seems to get worse within a week. The flat sample going into the keg tastes great, but then it all goes downhill. This isn't very obvious in my stouts and other beers...but I think they too get slightly "watered down" with time. I too have tasted the other things mentioned in this thread...slightly sour / green apple like, maybe a bit medicinal, etc. But it is super obvious in my Pale Ales and IPA's.

Like all of you, I'm getting really frustrated. IPA's are my favorite beer style. I'm extremely meticulous with my cleaning and sanitation, I've listened to all of the podcasts, searched the internet for hours and hours, etc, etc. Can't believe I finally stumbled onto this thread. It is exactly what I'm experiencing.

Here is what I've tried and ruled out...

1. Oxidized Hops - I recently made a Pale Ale with brand new vacuumed sealed hops from Hop Union, ordered from Northern Brewer. Did not make a difference.

2. Oxidation in general - I don't do a secondary and go straight from the fermentor to the keg. I started purging my kegs with CO2 and am VERY careful about not splashing the beer while racking to the keg. Didn't make a difference.

3. Water & Mash pH - I've been messing with my water constantly since I started brewing. I have an RO system in my kitchen so that is what I used. Then I learned that my city treats our water with Chloromines and that RO systems can't get rid of it, so I started using Campden tablets. I started using Gypsum and Calcium Chloride to create water profiles recommended by Tasty, Martin, AJ, etc, etc. I've tried adding the salts straight to the grain, then to all of the water before brewing, to the boil, etc, etc. I make sure my mash pH is between 5.2 and 5.4. I've treated the mash with Lactic Acid and also have treated the water before mashing in. None of this has seemed to make a difference as far as this problem is concerned. In fact my last Pale Ale was right at 5.4 without any addition of Lactic Acid, so it's not the Lactic Acid either.

I recently joined our local home brew club and was really surprised that almost NOBODY treats their water with Campden Tablets OR uses RO water. Most just run their tap water through a carbon filter and don't mess with it at all...and I've tasted some really nice beers of theirs, including IPA's. So I'm going to try this next.

4. Slight Infection - Here is where things get interesting. I've become overly crazy about sanitation thanks to this problem. But having a REALLY SLIGHT / MILD infection is one thing that's been in the back of my mind. I think it might be the ONLY thing that can zap the flavor of the amount of hops that I'm using in my IPA's. I also think if my stouts had this really slight infection that it would be hard to detect, but still there...which I think I've tasted. I think this might be why they are nice and rich and malty in the beginning, but lose that complexity over time.

I made a fresh batch of Star San a few weeks ago when I brewed Rye IPA. A few days ago I kegged a batch of Belgian Wit and just for fun I tested it with my pH meter and it was 4.4. Star San is supposed to only be effective if it is lower than 3.5. So I made a fresh batch of Star San and it was 4.2!! I talked to someone at Five Star and they said that Star San can lose it's effectiveness after 1 year! They said that I could try adding more Star San to compensate, but that I can't exceed 300 ppm or it will require a "rinse" before using. The limit is 1.5 oz for 5 gallons. There is no "expiration date" on the bottle, and I have never heard or read of anyone mentioning this. Not online or anywhere else. There are several posts about how long a "Mixed" batch of Star San will keep, but not the bottle of Star San itself. How many local home brew shops have bottles of Star San sitting on the shelves for over a year before they are purchased? So this really baffled me. I have never heard anything about it. Surely if this were happening to lots of people we would have heard about it? Not sure.

So that is where I'm at with this currently. I have also never ran a brush through the serving tube of my kegs. I just soak them in PBW for 20 minutes and run it through the lines, rinse with water, and run Star San through the lines before serving.

If I ever figure this out I will definitely report back.

 

[stewart194]

Thanks for the reply. Yes I've steeped hops for 20 minutes and 40 minutes after killing the boil and it didn't fix the problem. I've also tried to cool the wort down to 170 before throwing the hops in. Just didn't make a difference in this case.