Identifying an off-flavor, coming up short on ideas

[Jakeintoledo]

I'll apologize if my post is like reading War and Peace, but in the sake of leaving no stone unturned, I'm trying to identify an off-flavor I have in my beers.

I've been brewing since Christmas 2010. All throughout 2011, I brewed beers for bottling, and generally speaking, thought I was getting good at it. In early 2012, I bought a fridge and a keg setup, and started kegging. Since kegging, I can't seem to nail a beer right, without an off-flavor present in the background. it's slight, but enough to make me want to get rid of it, and it's in most of the beers i brew, with no exception that I can think of.

The off-flavor is hard to describe; I'm sitting here typing as I drink a Maibock I made in the fall of last year, and which lagered for months. It tastes malty and sort of hoppy, like I like it, but there's also a background.....'sweetness' or 'tartness' to it. It's by no means hugely apparent. it comes out more in the aftertaste of the beer, too.

My sanitation is as such: I sanitize boil keg and fittings with PBW, then follow up with Star San. I also do this with my kegs; get water as hot as I can stand it, load it with PBW, let soak and scrub, then pressurize kegs with a compressor and slowly flow it out of the fittings. then I rinse and flow out of the kegs, then sanitize and flow out of the kegs. I also sanitize all the tubing i use post-boil as well, along with the plastic carboys i use.

My suspicion is in how I handle my yeast. historically, even on high gravity beers, I wouldn't do a yeast starter. I would do a smack pack from Wyeast, let it swell on up, and pitch it. Then I'd agitate it for about 20-30 seconds. that's it.

in reading, it seems that most people do a starter even for a modest gravity beer (1.050 - 1.060). and it also seems that people really like to aerate the heck out of their beer. though I've never done this with any of my beers, the beer I brewed to be bottled never seemed to show this off flavor.

I recently brewed an Altbier that I did a starter for, and which I aerated using a filtered aquarium pump and stone for about an hour. I'm attempting to give the yeast ideal conditions in which to thrive, to see if this problem goes away.

Your thoughts would be appreciated, and likely tried, especially if this Altbier comes through with this flavor.

 

[betarhoalphadelta]

Simple question: did you replace all the o-rings on any kegs you have? If they had been used for soda syrup previously, I'm told that flavor lingers quite terribly.

 

[Jakeintoledo]

Simple question: did you replace all the o-rings on any kegs you have? If they had been used for soda syrup previously, I'm told that flavor lingers quite terribly.

I did. When I bought my kegs, I completely disassembled them, soaked the steel in PBW for an hour, rinsed, replaced O-rings, and sanitized. I scrubbed out the inside and soaked with PBW for a half hour as well. I soaked the dip tubes in PBW.

 

[DrunkleJon]

Force Carb or Set and Forget? AG/PM/Extract? Age of ingredients?

 

[Yooper]

Since this off-flavor seems to be across all beers, we need to consider the common ingredients and/or techniques.

The very first thing I think of is water. Is your water source the same in all the batches?

 

[Jakeintoledo]

Force Carb or Set and Forget? AG/PM/Extract? Age of ingredients?

I've done both. Usually prefer set and forget, only because force carbing, for me, ends up in a foamy mess.

always all-grain. I've had the LHBS guy have to open bags, and his inventory moves pretty fast. I'd be surprised if the grain sits three weeks. I'm usually using standard two-row stuff.

 

[Jakeintoledo]

Since this off-flavor seems to be across all beers, we need to consider the common ingredients and/or techniques.

The very first thing I think of is water. Is your water source the same in all the batches?

Yes, standard Toledo Tap Water. The thing of it is, I've looked into the water at the LHBS, and they say that Toledo water is actually pretty reasonable. That said, it's reasonable to suspect that my water (in my neighborhood or whatever) has something going on with it.

My Altbier experiment used all bottled mineral water. couldn't find RO water anywhere, so went with bottled mineral water.

 

[Jakeintoledo]

Since this off-flavor seems to be across all beers, we need to consider the common ingredients and/or techniques.

The very first thing I think of is water. Is your water source the same in all the batches?

and if the issue were biological, I'd think that an hour boil would resolve that, wouldn't it? Or are you thinking of a mineral presence or something?

 

[Misplaced_Canuck]

... then pressurize kegs with a compressor and slowly flow it out of the fittings. then I rinse and flow out of the kegs, then sanitize and flow out of the kegs.

Is this a standard compressor used for tools? Most of these (not all) use oil to lubricate the tools/compressor head. Also, the humidity in the compressed air can easily harbor bacteria.

If you want to do a pressurized flush out, use CO2, not compressed air.

MC

 

[ronsky]

Some one already posted my thoughts on this... Too late to the keg party.

 

[Yooper]

and if the issue were biological, I'd think that an hour boil would resolve that, wouldn't it? Or are you thinking of a mineral presence or something?

I'm thinking too many minerals, or high bicarbonate water in the brewing water, or chlorine (or chloramines) in the brewing water.

It's possible that it's an issue with the kegs, but I can't think of anything that it could be.

 

[Jakeintoledo]

Is this a standard compressor used for tools? Most of these (not all) use oil to lubricate the tools/compressor head. Also, the humidity in the compressed air can easily harbor bacteria.

If you want to do a pressurized flush out, use CO2, not compressed air.

MC

This is an 'oilless' compressor. It could still be throwing off something....and that something could be getting caught in the ball lock, then entrained as I carbonate.

NEVER occurred to me that this could be going on. I use a compressor because it's expensive to fill a 5gal keg with sanitation product, when I could fill it up with a gallon, use a compressor to compress it, then rinse it out.

This is actually something that never occurred to me. I will skip the compressor sanitation, and will disassemble, sanitize and re-fit all kegs with new seals.

 

[Bennywisest]

Jake, Do you have results on the Altbier experiment yet? I am wondering if the off flavors you are getting are from underpitching/underareating your yeast, and you are getting Diacetyl flavors coming through. They can be butterscotchy in flavor, which may be perceived as sweet.

How long do you generally leave the beer on the yeast cake during fermentation? If you move to secondary or bottle/keg soon after fermentation is complete, the yeast may not be cleaning up Diacetyl.

I am not sure if this is the answer, since you say you always underpitched the yeast. But maybe bottle conditioning allowed for the yeast to have better contact with the brew and cleanup the flavors better than in a keg?

 

[Clonefan94]

This is an 'oilless' compressor. It could still be throwing off something....and that something could be getting caught in the ball lock, then entrained as I carbonate.

NEVER occurred to me that this could be going on. I use a compressor because it's expensive to fill a 5gal keg with sanitation product, when I could fill it up with a gallon, use a compressor to compress it, then rinse it out.

This is actually something that never occurred to me. I will skip the compressor sanitation, and will disassemble, sanitize and re-fit all kegs with new seals.

Even if it's oilless, Those compressors can hold a lot of nasties. I just think of all the water that comes out of my tank when I open the valve on the bottom and it makes me cringe about possibly having any of that get into my keg.

 

[Misplaced_Canuck]

Even if it's oilless, Those compressors can hold a lot of nasties. I just think of all the water that comes out of my tank when I open the valve on the bottom and it makes me cringe about possibly having any of that get into my keg.

Very true.

Also, you don't need to push out all 5 gallons of solution, in fact, there's no need to make 5-gallons of it. Just make 1-gallon, shake it around for a minute, then apply just enough CO2 to push some of the liquid out. That's what I do anyways.

MC

 

[Jakeintoledo]

Jake, Do you have results on the Altbier experiment yet? I am wondering if the off flavors you are getting are from underpitching/underareating your yeast, and you are getting Diacetyl flavors coming through. They can be butterscotchy in flavor, which may be perceived as sweet.

How long do you generally leave the beer on the yeast cake during fermentation? If you move to secondary or bottle/keg soon after fermentation is complete, the yeast may not be cleaning up Diacetyl.

I am not sure if this is the answer, since you say you always underpitched the yeast. But maybe bottle conditioning allowed for the yeast to have better contact with the brew and cleanup the flavors better than in a keg?

Benny, I do not have results on the altbier yet. Seeing the bubbler slowing down, decided to take a gravity reading (very carefully, thoroughly washing the thief and soaking it in Star San before dipping). I'm at 1.020. I usually taste the samples, and while I think I made this beer waaaaay too bitter, I detect zero off flavor so far. but I can't say as whether I ever remember detecting the off-flavor in a fermenter in the past.

Your post, however, has made me decide to bottle half of the batch (or at least part of it) and carbonate it the way I used to do, when I would get better results; using corn sugar dissolved in water and pitched right before bottling.

 

[Jakeintoledo]

Even if it's oilless, Those compressors can hold a lot of nasties. I just think of all the water that comes out of my tank when I open the valve on the bottom and it makes me cringe about possibly having any of that get into my keg.

Well, the only reason why i ever started doing this in the first place is because CO2 is expensive, and I didn't want to waste it. I never use a compressor to propel beer, just cleaning solutions. But I can see, from a contamination standpoint, where residual moisture could potentially get trapped in the IN lock, only to get blown out onto the beer when I pressurize it with CO2 in my fridge.

 

[Jakeintoledo]

Very true.

Also, you don't need to push out all 5 gallons of solution, in fact, there's no need to make 5-gallons of it. Just make 1-gallon, shake it around for a minute, then apply just enough CO2 to push some of the liquid out. That's what I do anyways.

MC

My interest was in saving the cost of CO2 by doing this. I typically would just make a gallon of PBW and Star San and blow it out using the compressor. then after rinsing the keg out, I'd fill and carbonate using the CO2 at that point.

It's definitely a step I overlooked, given how I was only doing this with the washing step, never concluded that I could trap nasties in the airlock.

 

[Yooper]

Benny, I do not have results on the altbier yet. Seeing the bubbler slowing down, decided to take a gravity reading (very carefully, thoroughly washing the thief and soaking it in Star San before dipping). I'm at 1.020. I usually taste the samples, and while I think I made this beer waaaaay too bitter, I detect zero off flavor so far. but I can't say as whether I ever remember detecting the off-flavor in a fermenter in the past.

Your post, however, has made me decide to bottle half of the batch (or at least part of it) and carbonate it the way I used to do, when I would get better results; using corn sugar dissolved in water and pitched right before bottling.

That's a great way to do it! If both have the flavor, you know it's in the brewing process. If only the kegged sample does, you know it's the keg process.

My interest was in saving the cost of CO2 by doing this. I typically would just make a gallon of PBW and Star San and blow it out using the compressor. then after rinsing the keg out, I'd fill and carbonate using the CO2 at that point.

It's definitely a step I overlooked, given how I was only doing this with the washing step, never concluded that I could trap nasties in the airlock.

Using a gallon of star-san and pushing it with c02 would use such a small amount of c02 that I don't think there would be any savings. But if you don't want to waste co2 that way, I'd just take off the posts and clean the keg thoroughly, rinse, and then sanitize with star-san and put it back together. No blowing out or using of gas at all.

 

[Jakeintoledo]

Just wanted to give everyone an update; I cold-crashed the carboy of Altbier yesterday in hopes of getting some of that not-very-flocculent German Ale yeast to settle down.

I bottled a case of it using DME for carbonation, and kegged the other half. Got a case in bottles and about a gallon-and-change in the keg. I sanitized the BEJEEZUS out of that keg.

 

[Phunhog]

My thoughts are that it is either the compressor or yeast health. If it is a yeast issue (underpitching) maybe you never noticed when you bottled since I assume you bottle conditioned all of your beers. The yeast cleaned up any off flavors during the warm conditioning phase. When you started to keg.....the keg goes into the kegerator and the yeast get cold and flocculate to the bottom. They never get a chance to clean up the beer.

 

[+HopSpunge+]

Oxidized copper imersion wort chiller?

 

[Jakeintoledo]

Jake, Do you have results on the Altbier experiment yet? I am wondering if the off flavors you are getting are from underpitching/underareating your yeast, and you are getting Diacetyl flavors coming through. They can be butterscotchy in flavor, which may be perceived as sweet.
How long do you generally leave the beer on the yeast cake during fermentation? If you move to secondary or bottle/keg soon after fermentation is complete, the yeast may not be cleaning up Diacetyl.

I am not sure if this is the answer, since you say you always underpitched the yeast. But maybe bottle conditioning allowed for the yeast to have better contact with the brew and cleanup the flavors better than in a keg?

You may be onto something. I could almost suggest that the flavor is a butterscotchy flavor. I am now doing a starter for everything I brew.

The Altbier experiment came through great. It actually came out more as a nut brown ale type of flavor than what I've had as an altbier, but I'd bet with a little tweaking, I could get it right. Of course, that wasn't the real purpose of the brew.

THe trouble is, I thought I was onto something when I found absolutely NO sign of it anywhere. Then I brewed a few more beers; an ESB and an Oktoberfest. I detected the flavor in the ESB.

So, to the diacetyl notion. I just looked at brewing notes, and I see that the Altbier got into bottles and force-carbed only 5 days after fermentation started.

the ESB sat in fermentation for about 17 days (I believe I put it into a secondary) before I kegged it.

Maybe as a continuation of this experiment, I might bring every beer I brew up out of my cellar, where it ferments at about 60-65, and sit for two days in my kitchen, where it's closer to 70-75 throughout the day....thoughts on that?

 

[xfjxdgykfdhu]

I've done both. Usually prefer set and forget,

 

[Grippe]

Scientific method - brew batches just as you normally would with making some distinct changes to isolate the specific influence you're detecting:

1. Brew a batch with spring water from another source (Crystal Geyser for example)
2. Don't keg - bottle a different batch
3. Order grains/hops/yeast from a different HBS store
4. etc

 

[grathan]

Try bottled water one time.