oxidation question?

I have recently been allowing my barleywines and other beers that are about 10.5-12% abv to age in the seconary fermenter for around 6-8 weeks. I have noticed a very strong oxidation flavor in my brews and I have also noticed that after a period of time, the carboy is actually pulling air into it through the airlock. Its like a reverse flow. Has anyone experienced this?

I also wonder if its my brewing process contributing to the long term stability of my beer. I usually take about an hour to sparge with no splashing of any kind using a tube and it usually takes about 3-4 hours for my beer to cool in the brew pot with the lid on. I cool the pot in a big tub of water.

Thank you in advance for any input.

Hot side aeration is a topic that has much debate. Theory is that hot side aeration will affect beers that are stored for a long time (much longer than 6 - 8 weeks). Due to this many professionals will not use copper in any part of the HLT, MLT, or kettle.

Cold side aeration is much more common, usually occurring during the bottling process.

As temperature and pressure change carboys/buckets will draw in through the airlock, happens all of the time.

Can you describe the oxidation flavor that you have? Oxidation usually tastes like cardboard.

I'm not a fan of using a secondary fermenter for just this reason. After the ferment I put my beer in a keg, seal it up, purge with co2 and let it age in the keg.

I don't think hot side aeration has nearly the effect that some people claim. I'm inclined to think that your oxidation problems come from the extended time in the secondary. That's my 2 cents

What flavors are you picking up, exactly, that you're associating with oxidation? It's possible that you've got something else going on altogether, and maybe we can help with that. Or, it could be truly oxidation and then we'd be best off helping to investigate that. But a little more info will help us all make sure we're helping chase down the right problem!

cfonnes said:

Hot side aeration is a topic that has much debate. Theory is that hot side aeration will affect beers that are stored for a long time (much longer than 6 - 8 weeks). Due to this many professionals will not use copper in any part of the HLT, MLT, or kettle.

Cold side aeration is much more common, usually occurring during the bottling process.

As temperature and pressure change carboys/buckets will draw in through the airlock, happens all of the time.

Can you describe the oxidation flavor that you have? Oxidation usually tastes like cardboard.

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My impression of hot side aeration is that it not something to worry about. Also, what does copper have to do with it? Copper is indeed used throughout the hot side process.

To the OP - if you minimize the amount of headspace in your secondary, you'll limit 1) the surface area potentially exposed to oxygen and 2) have minimal, if any, "suck back"'through the airlock. Suck back occurs when there's a lot of headspace and a drop in temp. The drop in temp causes the gasses in the headspace to contract, creating a vacuum and sucking air in.

How big is your secondary and how much volume are you filling it with?

JLem said:

Also, what does copper have to do with it? Copper is indeed used throughout the hot side process.

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This is a good explanation from BYO. There is a lot of information on hot side aeration available by searching the internet.

Iron and Copper love to get oxidized. Just imagine what rust and blue-green copper can do for your beers flavor. Not very tasty. The various metals used in pipes and brewing vessels, along with your water supply can be a source of them.

http://***********/component/content/article/20/1835

Also, glass carboys are not oxygen permeable but plastic fermenting buckets are. I have heard that it's not a good idea to go over 4 weeks in a bucket for this reason.

cfonnes said:

This is a good explanation from BYO. There is a lot of information on hot side aeration available by searching the internet.

Iron and Copper love to get oxidized. Just imagine what rust and blue-green copper can do for your beers flavor. Not very tasty. The various metals used in pipes and brewing vessels, along with your water supply can be a source of them.

http://***********/component/content/article/20/1835

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Indeed metals can be oxidized, but this will not cause your beer to be oxidized...in fact, if the metal is being oxidized it means there is less oxygen to interact with the beer compounds so oxidation of the beer will be lessened. Besides the piece you quote is about metallic off-flavors associated with oxidized metals not with the off flavors associated with oxidized beer.

There's a podcast out there (i forget which one, but will try to find it) in which Dr. Charlie Bamforth debunks the importance of hotside aeration. Or at least he plays it down as a major concern. It really isn't something that we need to worry too much about.

here's the podcast I mentioned above - http://thebrewingnetwork.com/shows/475

Ok, I'm going to eliminate hot side oxidation for sure. The flavor is slightly metalic like pennies, and yes, maybe a little cardboard and a little solvent like.

dkbanjo said:

Ok, I'm going to eliminate hot side oxidation for sure. The flavor is a little harsh, slightly metalic like pennies, and yes, maybe a little cardboard.

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Oxidation tastes more like wet paper or wet cardboard. Not harsh or metallic

harsh and solvent could come from the alcohol. This is a flaw caused by fermenting at high temps. It's much harder to manage this in higher strength beers

While the cardboard does sound like a potential oxidation issue, the "metallic" note doesn't, and neither does the "solvent" character.

So, a couple questions: First off, what kind of temperatures are you fermenting at? do you have any temp control at play? The solvent character can be indicative of fusel alcohols, which tend to crop up from fermentations that are much too warm (typically in the upper 70's, lower 80's and beyond, where most ale yeasts prefer low to mid 60's). Keep in mind that doesn't mean ambient low to mid 60's - during fermentation, your beer is going to be 5-10 degrees warmer than the room it's in!

I think that metallic notes can come from fusels too, but I'm more familiar with them coming from over carbonation. How do you serve your beer? Bottles or draft? Either way, it could be possible that you've slightly overcarbed the beer, and what you're picking up is what's referred to as carbonic bite - it's typically picked up as tasting like pennies. Depending on how the beer is packaged, this can be easy, or more difficult, to remedy. If kegged, simply back off the pressure by a couple PSI and give it a few days to off gas and you should see an improvement. In the bottles? Try pouring the beer and letting it sit for a minute or three before drinking, and it just might off gas enough to lose enough bite.

The fusels, if that's what you've got going on with the solventy character, sadly, aren't going to go away.

Here's my brewing equipment...
-70qt colemen extreme/with stainless braided line for a manifold and 2' vinyl tube for draining into the brewpot.
-I switched to a stainless brew pot from aluminum on my last batch. but both have similar flavors.
-two glass carboys
-vinyl siphon tube
-all stainless cookware such as my spoon.
-and i just used my new 2.5 gallon keg for the first time.

I ferment at 65-72 maximun. I have a stick on thermometer. It has the same tastes from both the bottles and the keg. I've had it kegged for about 2 months and the flavor is getting more pronounced as it sits. I just dry hopped my rye.p.a and tasted it from the secondary and it has a similar flavor too. ggrrr
thanks for the advice so far, its really helpful.

OK, 65-72 maximum, but what strain of yeast? For many strains of yeasts, that's their happy place. For some, not so much.

Now, you're noticing something in secondary - which tells me that it's not carbonic bite. So, what exactly is it that you picked up in the secondary? Which one (or more) of those things you described?

I hope I'm not causing alarm for no reason, but I had a batch go bad, which then spread to another keg. It had a weird tang or bite to it, almost metallic, and it got worse over time. It started tasting solvent-like. I had these kegs stored out in a freezer in the garage (temp controlled but with no taps). I was using a picnic tap to test the various batches out. I found the bad one, dumped it. Later, I found a second keg started tasting the same way, a bit milder but just the same. I figure I spread the problem by using the same picnic tap to sample the infected keg, then the second keg. No cardboard taste however.

[Edit] my point is, it could be infection if it is in multiple batches.

hmm, I use sani-clean on everything I own and I always use a little more then it says. Although, is it possible that my siphon tube, even though I use sanitizer, could be causing a problem such as infection? I have not replaced the tube for about two years.

well, thinking further thru the "infected" question, I would think it would be tubing, carboys, yeast pitching, anything post-boil and pre-ferment. I don't know your procedure to guess. If you don't have a kettle valve you are siphoning out of the kettle? Is it an easy siphon or a racking cane? Once people see or even suspect infection they usually throw out and replace plastic parts and clean the crap out of all the metal.

Also, are you washing/re-using yeast? Another potential source.

No re-using yeast, too scared for that reason. I think its a racking cane I use. Its about 2' tall and you pump it to start the siphon. The beer tasts great going from the primary to the secondary (I sample the hydrometer test tube, then throw out the rest, never pour back) then then I sample the beer before dry hoping after its been in the secondary and thats when I start to get that flavor. Then after its bottled or kegged its very pronounced. I really wash the hell out of my carboys but never have used a brush. I soak them in hot water for a few days for the scum to loosen up. then wash them out. Then sanitize them.

I'm going to apologize up front for what probably sound like dumb questions now, but I'm just trying to get a level set:

Sounds like everything's alright through primary. So, walk us through your process to transfer to secondary, and don't leave anything out.

Do you sanitize the secondary immediately before you transfer your beer into it? You're using saniclean as a sanitizer. Are you rinsing it or letting it dry, or leaving it wet on your secondary vessel?

What you just described is definitely a siphon and siphon tube. Are you fully sanitizing that, inside and out? Again, are you rinsing or letting that dry, or leaving it wet with your sanitizer when you use it?

No judgements here - just trying to figure out what's going on. It's starting to sound like you may be picking something up during the transfer from primary to secondary, and maybe we can track down something in your process that could be allowing for that. Or, maybe your process is flawless and your equipment (likely your siphon and related tubing) have become suspect and it's time to drop $20 or $30 on a new set.

dkbanjo said:

-and i just used my new 2.5 gallon keg for the first time.

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Did you notice this when you started using this new keg? how did you clean the keg out before you filled it? Have you taken the posts off and inspected the popits?

No need to appologize, I'm greatful for the help. there nothing like buying 20lbs of grain, 8ozs of hops, yeast, and it all going to waste.

Heres my transfer day...
I wash secondary with warm water then drain.
Fill again with warm water and add sani-clean.
I rinse off the siphon tube and I then insert both ends into the secondary submerging as much of the tubing as possible (both the flexable and non-flexable ends).
Then I pump the siphon tube to fill the tubing with sanitizer, and I continue to recirculate it for a few minuts.
Then I fill a small pail with a separate solution of sanitizer, and thats where i put my airlock.
After everything has sat awhile, I drain everything and do not rinse with water. I just drain and air dry.
I then transfer to secondary and take a gravity reading, and I never pour it back.
I put the air lock on and done deal.

Sometimes the vessel and siphon are not COMPLETEY dry of the sani-clean solution. This has also been happening before th new keg but its more noticable coming out of the keg then the bottle. The bottles arent even carbonated.

Solvent flavor is sometimes a product of a wild yeast infection

Two things jump out at me:

One: cleaning with just water isn't enough. Get some oxy clean free, or pbw, or something along those lines. You want an actual cleansing agent in there, to make sore you really are cleaning everything adequately.

Two: don't allow the sanitized items to dry! Saniclean and starsan are contact sanitizers - they sanitize surfaces, and then they provide a protective barrier of sorts as long as the surface is wet with the sanitizer. As soon as its dry, it's no longer sanitary.

Ok, thanks for the clarification on the sani clean. I will use it while wet. I ordered a new siphon and tubing just to be safe. As for the wild yeast, that brings me back to what I was saying about the secondary air lock doing a reverse flow of air after a few weeks. Instead of it just sitting there and/or air leaving the vessel, it actually creates a vacuum an pulls air in. The temp is very stable(give or take a few degrees). Should i just put a stopper on it with no air lock on it after a few weeks? That could prevent wild yeast from coming in couldn't't it?

I wouldn't worry about the air lock - as long as you're keeping the air lock filled with sanitizer or vodka, then no bugs or yeast are making their way through and into your beer. You really don't want to put a stopper on the carboy.

As for the new siphon and tubing, that's a decent precaution - but make sure that you take care of the two process issues we've found first and foremost:
1) it really sounds like you're rinsing, and not cleaning, your fermenters. You need to find yourself a good cleaner/cleanser and start using it to make sure you have a truly clean surface, or no amount of sanitizer is going to help you out!
2) you need to make sure you're using your sanitizer correctly

Those two steps should help to address these off flavors you're noticing. I'm still a bit perplexed, though, at why you're noticing this in the secondary only, and not in the primary, as I'd imagine you're handling your primary in the same way...

sorry for the late response, I had to go to class.
When I'm done with the fermenters I use cascade before I store them and I sanitize them before use. Maybe I should try something else. I dont use sanitizer or vodka in the airlocks though. As long as air being sucked into the secondary isnt a problem, I'm perplexed as well. I've been brewing for about 3-4 years and this has just been a recent thing. the only thing I changed was aging my beer in the secondary from about 2 weeks(old method) to 6-8 (new method). I started aging them longer, so I always have a beer waiting to be bottled between brew days.

What do you mean you don't use sanitizer or vodka in the airlock? What do you use? And yeah, I kinda think air sucking back into the secondary is kind of a big deal. Prolly not causing the same off flavor in every batch, hut something you would want to eliminate from occurring.

I found the same thing when I used to secondary. I did some reading and believe it is from a secondary reaction converting ethanol to acetic acid (vinegar), which happens with oxygen and warm temperatures. Two ways to deal with it - secondary in a fridge, or purge your secondary with CO2 before racking into it. I just gave up on secondary and simply do an extended primary, then right into the keg for cold crash. Never happened since. Also, throw a couple bags of ice in your tub, and your wort will cool down much faster. I did that before buying an immersion chiller.

Even if you keep filling the airlock, you should still be concerned about the suck back. Every time that happens, it is also sucking in air, filled with oxygen and bacteria and wild yeast.

The way to avoid suckback in secondary is to make sure you limit the headspace by filling it as completely as possible.

Or just skip the secondary and put the beer in a keg for aging.

You may also consider using the S shaped 2 bubble style airlock instead of the three piece kind. It will allow "suck back" without draining the sanitizer back into the vessel and any air that comes through will at least have passed through sanitizer first.

wittmania said:

You may also consider using the S shaped 2 bubble style airlock instead of the three piece kind. It will allow "suck back" without draining the sanitizer back into the vessel and any air that comes through will at least have passed through sanitizer first.

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This doesn't make the air sanitary... And airlock is designed to let positive pressure out. If a vacuum occurs, either limit headspace or use a solid bung, or both.

tcbailey said:

I found the same thing when I used to secondary. I did some reading and believe it is from a secondary reaction converting ethanol to acetic acid (vinegar), which happens with oxygen and warm temperatures. Two ways to deal with it - secondary in a fridge, or purge your secondary with CO2 before racking into it. I just gave up on secondary and simply do an extended primary, then right into the keg for cold crash. Never happened since.

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Interesting. I hadn't heard of this. Do you have a source? I always blast a secondary with co2 for a few seconds before racking anyway.

I would also eliminate cleaning with Cascade it has detergents and perfumes in it. Get some PBW or Oxyclean (the kind without scent).

Use sanitized water or vodka in the airlock.

I don't know if these have any effect on your beers but certainly would be safer.

IMO unless you get EXTREME amounts of air sucked through the airlock oxidation from that is unlikely. The oxygen is lighter than the co2 so it should not get to the beer. It would stay on top of the co2 layer. Infection is a possibility though. Using sanitized water or vodka would lessen the chance of this.

tcbailey said:

I found the same thing when I used to secondary. I did some reading and believe it is from a secondary reaction converting ethanol to acetic acid (vinegar), which happens with oxygen and warm temperatures. Two ways to deal with it - secondary in a fridge, or purge your secondary with CO2 before racking into it. I just gave up on secondary and simply do an extended primary, then right into the keg for cold crash. Never happened since. Also, throw a couple bags of ice in your tub, and your wort will cool down much faster. I did that before buying an immersion chiller.

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Ethanol can indeed be converted to acetic acid, and does require oxygen. However this is not a very common spontaneous chemical reaction. It is however common if you have some Acetobacter bacteria around (which is pretty common). This bacteria cannot survive in a oxygen depleted environment (fermented beer). However give it some oxygen and it will happily convert your beer to vinegar

Upshot is, having some oxygen exposure alone won't give you an acetic bite. You have to have contamination as well. Or if you have contamination (with acetobacter), just limit any O2 exposure and you'll be fine.

One thing that strikes me after reading these responses is that my batch sizes have become a little smaller (4.5 gallons sometimes). So limiting the head space could be part of it, because I had a feeling that a lot suckback cant be good. Infection Could be the other part of it. For my next brew day, which wil be in a couple of weeks I'm going to to the following....
-clean vessels with oxyclean (we sell it at work).
-use sanitizing solution in airlock.
-get a two chamber air lock for secondary(so no sanitizer gets sucked back into vessel, just incase) or solid bung.
-replace all plastic parts.
-make an immersion chiller to cool wort faster(we sell soft copper at work).
-make my batch bigger to limit head space.
-and purge vessel with co2 before transfer.

This sounds like a lot, but it really isnt. I wish I could have a separate fridge for cold storage and more kegs, but space is an issue. I'm really excited to try these suggestions. If any one has any others I'm open to here them, otherwise, thank you everbody. This was a great first experience on a forum for brewing.