Off Flavor - Oxidation?

I've been battling an off flavor in my pale ales for a while now. My brown ales and belgians have been coming out great, but my pale ales and IPAs always have a taste that bothers me. I've been working to solve the mystery for a while now, because I really like hoppy beers, but without much luck.

The best I can describe the flavor as is dull, vegetal, maybe caramel-like. I can smell it as well as taste it. It always seems to appear after dry-hopping; the first sample out of the primary typically tastes bright and clean, but after dosing it with dry-hops and carbing I'm smacked with the off flavor.

I've tried playing with pH and water additions. I heard a podcast where Gordon Strong said high mash ph combined with hops makes for dull soapy flavors. I also thought lack of sulfates might be adding to the dull muttled flavor. Well my additions have improved my other beers but the problem persists.

My next thought was that it was the dry hop addition itself. I feel like the flavor does have a vegetal component. So I switched from pellet hops to whole hops. No luck.

I have also tried using gelatin and extended cold conditioning (35*). I thought maybe hop particles were to blame. This made brilliantly clear beer and a cleaner profile, but the flavor persisted. I also switched from 1450 to US-05, thinking that the suspended yeast were trapping unwanted particles. Nope. I started swear off dry hopping completely, but so many of the beers I like are dry-hopped, it doesn't make sense that this would be the problem. Plus, the sample I take from primary is full of hop particles, but it tastes bright and flavorful.

Today (like many other days before) I think I may have a good lead. Perhaps the problem is oxidation. These beers are the only ones that I transfer to a secondary. I'm pretty careful about splashing when I transfer (I use an auto-siphon and the end of the tub rests on the bottom of the secondary carboy), but I also don't purge the secondary with CO2. Perhaps the flavor I am tasting is the wet cardboard flavor people describe? When I think about it, it is reminiscent of flavors I get from an older commercial IPA.

Any thoughts?

Is this AG or Extract?

What are your dry hopping procedures- temp, amount of time? If left in too long, they lead to vegetal, grassy flavors.

Not a bad idea about the oxidation and secondary. FWIW, I dry hop all of my beers in primary with great results, and wouldn't even think about secondary at this point due to risk of infection or oxidation.

I brew AG batches. Although, I had the same issue on a 20-min extract/hop-burst batch. For dry-hopping procedure, I generally rack on top of the hops using the auto-siphon. I don't use a very large amount (1-2 ounces). And I leave it for 5-7 days. I started shortening the dry-hop to 5 days with the thought that maybe over-exposure was the problem. I dry-hop at room temp (70) or basement temp (60).

i had similar concerns about oxidation and i stopped using a secondary 2 batches ago. so far i found it to be easier and i'm not getting the off flavors.

What did your off-flavors taste like? Can you compare them to anything?

You could try to dry hop in the primary, I did that with my Amber Ale.

Yeah I think my options on the next one are no dry-hop or dry-hop in the primary. It's just frustrating having so many batches of pale ale come out poorly. I suppose for my next one I'll go smaller batch. Anyone else have any experience with oxidation from secondary?

Try adding a little boiled sugar solution to the secondary to create some CO2. I'm not a hops fan and I don't secondary much anymore. I don't think the flavor you describe is oxidation though. Vegal reminds me mainly of DMS.


http://www.bjcp.org/course/Class5Lesson1Troubleshooting.php

I agree with the above. Hop variety or length of dry hopping would seem most likely.

Yeah, after working on this for a while though, I feel like maybe I'm describing the flavor incorrectly. Perhaps the vegetal flavor I'm getting is hop flavors with oxidation over the top? I don't know. I'm pretty careful when racking but at this point I'm grasping at straw and oxidation seems to be the next best candidate.

Ive used a variety of hops; hops that I love in commercial beers (Amarillo, centennial, simcoe) and I've tried shortening my dry hop time to cut down possibility of grassy vegetal notes. With DMS... I don't cover my boil and I'm able to cool the wort fairly quickly (20 min)... Plus I don't get it in any of my other styles (wit, blonde, saison, brown).

The adding sugar idea is interesting. Something to consider. Any other thoughts welcome. I'd love to get to the bottom of it. I have a freezer stocked with hops that Id love to use. Such bummer when I get tropical fruit notes over top of muddled blech.

On a side note... The recipes I use are typically 2 row, Vienna, light crystal. Although I have used slight variations with Munich and rye and I also had the same problem with a batch of 20 min boil extract plus hop burst. I've also tried with 1450 and us-05.

Reading through this, it seems like you have two culprits: dry hop time and transferring to the secondary.

After reading through IPA, Mitch Steele indicates that maximum dry hopping oil extraction is complete after one day. One day! Sh*t blew my mind.

At any rate, try your next dry hop in the primary and report back. We'd all love to hear a happy ending!

So you think I should go primary dry-hop over no dry-hop? I've read about people adding dry hops just as fermentation is winding down so that they yeast can scrub any oxygen that might be added in the process. Should I try this strategy or just add after fermentation is complete? I know yeast in suspension can reduce the effectiveness of the dry hop but at this point I'm just looking for minimizing oxygen to rule it in or out. Any kind of nice clean hop flavor would be welcome at this point.

Also, if I'm following the Mitch Steele advise, I should rack after 24 hours of contact?

Honestly I wouldn't worry about dry hops adding enough oxygen to damage your beer in any way, unless you were adding tons and there was all kinds of splashing going on.

Yeah its just one of the few variables i have left. Since my other beers turn out so clean, it must have something to do with the tranfer to secondary and dry hop. Im open to any other thoughts...

I have had this EXACT same issue for a few years now. Every beer I make tastes fantastic EXCEPT my hoppy beers (both extract and AG). Regardless of whether I bottle or keg, my hoppy beers are perfect at early tastings in the primary or around the 1-week mark into carbonation, but after 2-3 weeks the bright, clean, hoppy flavor is gone. The best way I can describe my off flavor is "not clean", or "muddled", but like I said they taste perfect up until the point they're fully carbed. Do you notice the hop aroma disappears around the same time the off flavor comes in? Also, do you notice the color of the beer darkening a bit over the first couple weeks of carbonation?

I've tried a lot of these suggestions, ditching the secondary, dry-hopping at the tail end of fermentation so the yeast scrub out some oxygen, purging my carboy/keg with C02 before transferring, investing in quicker chilling equipment. None of it has worked.

My next attempt I'm switching from one LHBS to another that vacuum-seals all their pellet hops. I'm wondering if throwing in hops that may already be oxidized could be our culprit. I'll definitely let you know what I find out, but that won't be for another 1-2 months. I am as desperate and frustrated as you to find a solution for this weird flavor. I love IPAs and APAs, but these are the only two styles that I simply can't make a decent batch of.

Well that's a relief. At least I'm not the only one. I will report back on my latest. It's been one week in primary. I'm going to skip the dry hop. I know it won't be as hoppy, I'm just hoping for a clean hop profile.

I've also suspected old hops, but my last batch was dry hopped with fresh simcoe. My wife thinks I'm crazy that I keep brewing hoppy beers when my other beers turn out so well and I'm always disappointed with the pales.

Well I took a sample of the most recent pale/IPA... Fantastic. Bright citrus and floral hops. Now we'll see if that will translate to glass if I skip the secondary/dry-hop. I'm debating skipping the cold crash just to keep oxygen at an absolute minimum for this run. Anyone ever done cold crash with a solid stopper, or is that dangerous?

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?

tagz said:

Argh!! Well I kegged it up and it has that same stale flavor!

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Just a thought... could it be your kegging process? Older lines perhaps?

I actually just went through and cleaned all my lines and taps about a week ago. I'm assuming it must have some thing to do with the hops because all my other beers turn out great... Even light, delicate beers. I've ruled out so many factors that it must be my older batches of hops. I've switch to vacuum sealing in ball jars in the past year but those centennials and the Columbus spent some time rolled up in the freezer.

Thanks for the response. I'm willing to hear any new ideas/angles...

Could it be oxidation as a result of your kegging process?

I've been battling a similar off flavor issue w/ my kegged beers, and I'm now looking at oxidation. Doesn't happen when I bottle, only keg. Definitely frustrating....

Good thought. I'm pretty careful when I rack and I flush the keg with co2 before siphoning. Then I purge a bit before cranking the psi. The other thing is I just had a blonde ale on tap that had a crisp clean profile. I have a brown ale on right now that is really tasty. I only encounter the problem when I brew a pale or IPA, which is why I thought it had to be the dry hop in secondary... I don't secondary for anything else.

The only remaining thought is the old hops. I pulled out the centennial today and it smells okay but they are close to 2 years old now. I keep all my hops in vac sealed jars, but those were part of my first bulk purchase and they spent soe time rolled up in the bag in the freezer... I suppose I will brew a batch with only 2012 crop and see if i get a clean flavor. I just hate wasting all these batches... Even if they are 3 gallon size. Hopefully I will figure it out some day so I can enjoy brewing up some hoppy beers.

tagz said:

Good thought. I'm pretty careful when I rack and I flush the keg with co2 before siphoning. Then I purge a bit before cranking the psi. The other thing is I just had a blonde ale on tap that had a crisp clean profile. I have a brown ale on right now that is really tasty. I only encounter the problem when I brew a pale or IPA, which is why I thought it had to be the dry hop in secondary... I don't secondary for anything else.

The only remaining thought is the old hops. I pulled out the centennial today and it smells okay but they are close to 2 years old now. I keep all my hops in vac sealed jars, but those were part of my first bulk purchase and they spent soe time rolled up in the bag in the freezer... I suppose I will brew a batch with only 2012 crop and see if i get a clean flavor. I just hate wasting all these batches... Even if they are 3 gallon size. Hopefully I will figure it out some day so I can enjoy brewing up some hoppy beers.

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I get a stale taste if I carb with high psi. Instead I prime with sugar, just like bottles, then in 2 weeks hook it up to co2 at serving psi.

Interesting. I've been wanting to do a natural carb in the keg. Maybe I'll do it sooner rather than later. Anyone else experience dulled flavor with force carb?

This may be obvious, but describe your keg cleaning, rinsing, sanitizing, filling process in excruciating detail please. My first instinct is not old hops.

I clean the kegs with oxyclean right after use. I disassemble the parts and soak them individually as well. Then I rinse everything before storage. When I get it ready for use I soak all the parts individually with starsan and then assemble. I close it up and shake around some sanataizer and then dump. Occasinally ill use co2 to force sanatizer through the lines as well. I fill the keg with co2 and purge a bit while I'm getting set up for racking. Then I rack using an autosiphon into the keg. I seal it up, hit it with co2, and then purge a bit to let any remaining o2 out. I set it to 30 psi for 24 hours and serving pressure after that. I also experimented with doing a long carb at serving temp so I wouldn't look aromatics but that did make a difference in the off flavor.

Other styles turn out great on tap. Pales and IPAs not so much.

Drinking one now. The best way to describe it is it tastes like an out of date pale ale. Like I got a sixer at the store only to realize it was brewed 4 months ago. The weird part is that it tastes so good when I first sample it. But now it tastes like all the bright hop flavors are gone and I'm left with the grassy, herbal remnants.

What about mash pH ?? Do you know what the alkalinity of your water is??? Have you ever measured your mash pH??

If your darker beers are turning out fine...could be because the darker grains have adequate acidity in the mash to counter your alkalinity resulting in a mash in the right pH range.....but for the lighter beers there isn't enough acidity in the grainbill in the mash to offset the alkalinity resulting in a high pH....and tannin extraction, etc...and off flavors.

I had a buddy keep telling me my beers were oxidized till I started making starters or pitching double vials. He has since rescinded his comments. Just a thought.

I almost always notice a weird flavor, almost bitter and acidic at about a week in the keg. It goes away. I feel like carbonic acid would taste like that. Maybe from the fresh force carb? Not sure if it relates to the op's issue at all. Just another thought.

Are you dry hopping with columbus? That's a pretty pungent hop.

mgortel said:

What about mash pH ?? Do you know what the alkalinity of your water is??? Have you ever measured your mash pH??

If your darker beers are turning out fine...could be because the darker grains have adequate acidity in the mash to counter your alkalinity resulting in a mash in the right pH range.....but for the lighter beers there isn't enough acidity in the grainbill in the mash to offset the alkalinity resulting in a high pH....and tannin extraction, etc...and off flavors.

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Yeah, I went after mash pH a while back. I was thinking the same thing. Now I use lactic acid and brun water spreadsheet to adjust to about 5.3. Also take readings to confirm.

I did get some astringency when I first started all grain but haven't had a problem in some time. I brew lots of wits and blondes with no problem.

arghh! i cant figure this thing out! brewed a red ale this time. used fresh 2012 hops (ahtnanum and citra 2 oz spread across 10 min and FO). tasted fantastic out of the primary. big bright tropical flavor. hop aroma faded substantially by after carbing in the keg. so i threw in 2 ounces of dry hops for 4 days. it was super cloudy when i pulled out the dry hops, but big mango aroma with some musty orange from the ahtanum. then three days later its an herbal mess. tastes like every other hoppy beer i've made. just green, vegetal blech on the tongue. i've now officially tried everything. i don't get it.

i just scored 2nd and 3rd place metals for my wit and brown ale, so my process must be pretty solid. but, this hop thing is killing me.

I've had similar issues. Do the flavors get worse over time? My issues are diacetyl developing in the keg and eventually turning butterscotchy, I think, from dirty kegs/having never run a dip tube brush through the dip tubes and getting infection. The pales and IPAs start out tasting amazing the first week, then they change...
There wasn't gunk in the dip tubes, but there could be build up that BLC or PBW isn't getting off when I clean the kegs. I'm currently running an experiment where I'm going to bottle half and keg half a batch, see if they remain stable.
I feel your pain. It sucks to have an awesome beer, the best IPA you've had in a long time suddenly turn to sh*t.
Perhaps it isn't your issue, but things to think about.

Interesting. Let me know about your bottling experiment.

Ugh. My current beer, jamil's amber red ale with 2 oz dryhop (4 days), is getting worse and worse. Any aroma that was there at the beginning faded after a few days. The flavor has turned more and more vegetal and bitter. I'm really out of guesses at this point. I lean toward water chem, but I'm using brun water for acidification and calcium chloride and gypsum additions, and none of my numbers as way out of range. Man, the dryhop sack smelled so great...

tagz said:

Ugh. My current beer, jamil's amber red ale with 2 oz dryhop (4 days), is getting worse and worse. Any aroma that was there at the beginning faded after a few days. The flavor has turned more and more vegetal and bitter. I'm really out of guesses at this point. I lean toward water chem, but I'm using brun water for acidification and calcium chloride and gypsum additions, and none of my numbers as way out of range. Man, the dryhop sack smelled so great...

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When did you dry hop? I have dry hopped when the airlock was barely bubbling and it still blew out all the aroma. I ended up disappointed. I am speculating but try adding the dry hop when the fermentation is completely done.

Good thought. It was completely done and kegged. I dry hopped after pulling a glass or two, because the flavor was so minimal. I dry hopped in the keg. Warmed to 68. Only had to open it to pull the bag.

I'm in the same boat. Been battling this with my IPAs for a while now. We should trade bottles to compare. The taste is hard to describe, but often it tastes slightly "chemical" - grassy maybe. I have often attributed it to the fact that I have a difficult time getting a nice big malt profile on my IPAs, and this relative thinness in flavor allows the chemical taste to come through even more. I'm fairly positive it is not simply hop flavor that I am tasting.

At some point (when I get my act together), I am going to keg half a batch and bottle the other half. I can't believe this would be the issue, but I'm wondering if the CO2 I get from my local "welding supply" shop is contributing something to it. I don't know...

I have two 7.3 gallon conical fermenters that I use to minimize infection and oxidation, and although they have definitely improved my beers, they still don't completely get rid of the chemical taste in my pale beers.

And I use PBW to clean and starsan to sanitize my fermenters, kegs, etc...

By the way, are you on a well by any chance?

Here's just a thought, and you don't have to try it but I would consider brewing a "control" brew. Go to the store and get bottled drinking water and brew with that without adding any salts or other things to adjust your mash ph.

Only reason I say this is because I do this with all my beers and my IPA is by far the best one I brew. I dry hop as well. That way if you produce a great beer with the store bought bottled water, your culprit may have something to do with the water you have been using.

Just a thought.

That's the route I've been thinking. I made 2 decent pale ales when I first started brewing, and I'm pretty sure I was using Poland spring water at the time. I'll give that a go. And if that doesn't work I'm going to throw all my citra, galaxy, and simcoe into a bonfire to burn the evil spirits trapped inside them.

Or you can send them to me!! Haha!