Off flavors from not aerating with o2?

I have never used o2 to aerate my wort... Always been a shaker! The last three beers I have brewed (levitation clone, pale ale, blonde ale) have all had the exact same flavor that just doesn't seem right. I have been searching the off-flavor section of the bjcp website and I wanna say this is a slightly sour/bitter, creamed corn, vegetal flavor (although its not predominantly any of those, that's just what I settled on). I am VERY confident in my sanitation and my process of batch sparging in a 70 qt Coleman is very consistent. Not oxygenating wort seemed to be a common theme in the corrections categories next to the above listed off-flavors.

So my question is: have any of you ever experienced a flavor like this due to lack of o2 in primary ferm? The recipes were all different and I actually used 001, 1056, 05 respectively so it can't be the yeast. Will o2 v. Just shaking make that much of an impact?

Does "05" mean US-05 dry yeast? If so, you need not oxygenate wort when using that (just rehydrate it).

Perhaps an over abundance of DMS?

Yes, us05. I'm leaning towards DMS or acetaldahyde according to the bjcp site. Tastes to be what I think DMS is like, but I'm not guilty of any of the "common practices" leading to DMS. The o2thing can apparently lead to acetaldahyde and there is a tartness that makes me think maybe green apple (bit of a stretch though). Has anyone ever gotten either of these off flavors from not oxygenating? US-05 was only used in one of the three beers. They all share the same weird flavor

What are your pitch and ferment temps like?

lyonshead said:

Yes, us05. I'm leaning towards DMS or acetaldahyde according to the bjcp site. Tastes to be what I think DMS is like, but I'm not guilty of any of the "common practices" leading to DMS. The o2thing can apparently lead to acetaldahyde and there is a tartness that makes me think maybe green apple (bit of a stretch though). Has anyone ever gotten either of these off flavors from not oxygenating? US-05 was only used in one of the three beers. They all share the same weird flavor

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The green apple of acetaldahyde is not tart/sour per se. It is the flavor (actually mostly aroma in my limited experience with it). When I hear sour/bitter together like that I'm always inclined to ask - which is it? The other question about acetaldahyde I'd ask is how young is your beer you've tried?

My guess is it's not acetaldahyde but rather a bacterial infection, perhaps from the bottles or bottling process.

Big floyd: Pitch and control temp with Johnson a 419 and a ferm wrap. 68* for the first two, 60* for the us-05.

hanso: i hear what you're saying about infection but I really don't think that's it. It is a very consistent flavor with my last three beers. Infection seems to me like it wouldn't taste the exact same each time (it's certainly not ruining the beers either, I'm just nit picking). That's why I'm leaning towards a process issue. I appreciate what you're saying though. I'll have to get that much more anal about sanitization to rule it out for sure

I tapped the latest keg today. It's 4 weeks old today. Flavor seems to hang through the life of the beer though. Thanks for the insight so far

Hmm. Sounds like its not overpowering, but noticeable and annoying. OK you convinced me about not an infection. Would you describe it as sulfury?

I only have two other ideas for you.
How much yeast is still in suspension? Do you cold crash? The thing I'm getting at is are you tasting old yeast and getting subtle yeasty flavors?
Second is how clear is your wort going into the fermenter? Do you let any extra trub into the primary or does it pretty much all stay behind in the kettle due to a hop blocker or whirlpool and dip tube?

I whirl pool and siphon from the side. Try to leave trub behind, but no doubt plenty comes a long for the ride. (I am actually installing a side dip tube today... So that part of the process will be changing). I ferment in a glass Carboy and usually don't cold crash in it. Rather I just transfer to keg and them crash that to 40 degrees and carb to 2.5 volumes for 2 weeks.

I'm consistent with this 2 week primary, 2 week keg condition. I'm open to improving my process any way I need to. This sulfer thing has me intrigued. Could any of the above issues give me that?

Ok probably not for lack of floculation then.

As for my trub idea, what I'm getting at is that a little bit of trub is actually good for the yeast especially in an under oxygenated environment, without proper growth nutrient they will suffer in the ability to reproduce and spend all their time consuming the wort.

per Wyeast:
The unsaturated fatty acids found in wort trub can be utilized by yeast for membrane synthesis. If wort trub levels are low, yeast will need to synthesize more of these lipids and therefore will require more oxygen.

The reason I asked about sulfur is because often that's what people say the resultant flavor is when yeast don't have enough growth phase. I could be wrong because I don't have first hand experience with this off flavor.

Last line of question I have is what are your pitch rates for these beers? Do you use a calculator and a starter?

The three yeasts you listed are, as far as I know, exactly the same strain, btw. I tend to use US05 rather than the more expensive liquid counterparts like 001 and 1056 because at least with 05 you don't need a starter, there's enough in a single 11g packet to be a proper pitch rate for most mid gravity beers.

That's exactly why I switched to us-05. I used I do a 2l starter with a 10-1 L/g ratio of DME per Jamil. I switched so I wouldn't have to do that. I don't believe it's an under pitch, but I am feeling more and more confident that lack of o2 may be the culprit. The 50 dollar investment is worth it I'm sure! I really appreciate your thoughts. Im brewing next weekend, I should be able to get an o2 system by then... We shall see!

The off flavor described is DMS and its related to the malt and the boil as well as how quickly you chill.

Since DMS is not common in extract ill assume you are an AG brewer. You appear to not be boiling vigorously or long enough or with the lid on. Pilsner malt is a big contributor to DMS production.

You can increase boil time to 90 minutes and boil harder to drive DMS off and do not use a lid.

dMS can begin to reform if chill time is too long as well.

So I'm a super noob here (first post!), and feel free to ignore if this is obviously not the problem...

But have you considered your water? Could something have changed recently? I ask because it seems like that is something that might stay the same in all your brews.

It's actually a great comment, and I had considered it. But our city recently switched water sources... Weird I know. I run water through a charcoal filter and that's it. But the first of the three questioned batches was from the old source, last two from the new source. Same result! I DO need to get the specs from the city on our new water. Only thing I know is its obviously softer (I don't even use my water softener anymore).

This flavor has been consistent through the change though. I think I am going to be hyper focused next brew day on doing anything and everything to eliminate DMS/acetal. And see where that lands me

Another question did pop up in my head though. The way to get rid of DMS is to boil vigorously. I have recently been using anti-foam. The way it works from my view is that the initial foaming occurs but only climbs a few inches and then collapses on itself and never comes back. I'm not trapping precursors this way am I?

I don't think o2 is going to change anything. I have never used o2 and do not get any off flavors that I would attribute to the lack. Also if the lack of o2 was the problem it would have been that way in all your brews. I have used Fermcap to control foam and cannot detect any difference between brews with and ones without. I have stopped using it because it is silicone and it is recommended that you filter it out. I instead just watch the start of the boil carefully and set up a blowoff tube fro the fermentation.

Sorry that I have no suggestions on where to look but thought maybe this would lessen the worry about a couple.