Recurring off flavor, part 2.

[stevereno30]

Hey everyone. A months ago, I posted this thread: https://www.homebrewtalk.com/f36/recurring-off-flavor-488058/

Since then, I've had two more kegs come to fruition and get tapped. Initially I thought I had solved my problem. The first pull from each get was incredible! The first one was an Oktoberfest lager, the second was a heavily hopped IPA. Both had really nice malt character, were well balanced and extremely delicious! I thought I had finally killed this monster that had been haunting my beers since I began kegging.

I was wrong.

A couple days after tapping the Oktoberfest, I had some friends over to have some. It tasted good, but I detected that horrible sharp bitterness that I had tasted in other beers. It was slight, but noticeable for my hyper-critical palette. I hoped it was a fluke, or my imagination, so I ignored it. The next day, I tried it again. I could still taste it. It was faint, but there. On that same day, I tapped my IPA which had been sitting in the keg carbonating for 3 weeks. It was incredible! It was the first beer I've brewed since I started kegging that made me sad I only had 5 gallons! It was malty, but well balanced with a mountain of hops. It smelled like brew day (thank you aromatic malt!). I thought my troubles had finally come and gone!

The next day, I poured a single pint... and I could taste it. The malt had subsided (in 24 hours!) and the sharp bitter/sour taste was there. Not overwhelming, but definitely there.

The next day, which happens to be today, I poured a pint, hopeful that the flavor wouldn't be there. I was hoping it was just from whatever beer sat in the lines.... it was awful. No maltiness detected, no bright aromatic hop smell, just a nasty, sharp, bitter sour sh*t flavor. I grabbed a large 1L stein and poured until it was full. Dumped it without tasting, then pulled another pint. It tasted just as terrible. I'm compltetely lost. I would think "dirty lines! A dirty tap!," but I gave every element of my tap system a 6 hour Oxyclean soak, followed by a 24 hour Starsan soak. They're as clean as they can possibly be. The ONLY thing I can think of that would cause this is my CO2. It doesn't make sense, because as far as I know, CO2 doesn't go bad! Both tanks I have were hand-me-downs that sat unused outside through the coldest MN winter imaginable. The IPA and the Oktoberfest were both carbonated naturally. I decided that *maybe* the taste came from the CO2, so I decided to use the tried-and-true method I used bottling for so many years. Since neither tasted bad at tapping, could it be the CO2? Could it be that something in my CO2 tanks is fouling my beer, but it doesn't come in contact with the liquid until I've tapped since the pressure in the keg exceeds the pressure on the regulator until I've poured some? I've tried both tanks exclusively to make sure it wasn't one or the other, but the taste remains. I’m just baffled because I can’t imagine any bacteria completely ruining 5 gallons of beer in two days, and every time, it was two days or fewer. Any ideas?

 

[HausBrauerei_Harvey]

i would guess it's the CO2. My buddy spent about a year figuring this out for his buddy. I'll see if I can find the thread he wrote up about it.

Definitely sounds like a CO2 issue to me.

 

[HausBrauerei_Harvey]

here is the thread I was thinking of, hope it helps!

https://www.homebrewtalk.com/f13/wort-good-beer-bad-troubleshooting-needed-486456/

 

[Rev2010]

Where were your kegs made? This is a long shot, and I'm a total noob at kegging, but when researching kegs to buy I read of this sort of taste in a lot of reviews of China made kegs, something to do with not all of the keg is stainless or low quality steel not really ideal for beverage. Again, this is a long shot and I have no experience with China made kegs so this isn't one of those "don't buy it if it's from china" crap cause I definitely do not subscribe to that mentality for the most part. Just the first thing I thought of reading this after having read a numbers of reviews noting what seemed to be a very similar off taste.


Rev.

 

[stevereno30]

My kegs are all made stateside as far as I know. Old soda or beer kegs. Plus, the off flavors only come after tapping, which is why I feel it's bad co2 or something. I don't know how else all of the beer could go nasty in such a short time... That is unless I'm dumping a bacteria colony in pre-tapping.

Thanks for that thread. It seems my co2 is likely to blame. It is just odd that two different tanks with different regulators both give crap results. Also worth noting.. I tasted a sample I poured this afternoon and kept out all evening and the taste was better. Maybe it is just really poor quality gas. I'll write again next time I brew after swapping this tank.

 

[ChelisHubby]

Try bottling some of the beers before you keg just to prove that it is not some infection from fermentation.

 

[stevereno30]

I did this too just to be sure and the bottles were fine, if a little under carbed. But the flavors are not present at first tapping. They only appear the day after tapping. And since I've been carbonation with sugar, the only thing added to the beer after tapping is the serving co2. On a side note, my regulator is set to 15psi and my kegerator is at 50 degrees f. Is this ok?

 

[MKBoitnott]

As far as co2 goes, in the recent issue of BYO magazine (or maybe it was Zymurgy) there was an entire article about how much we take co2 for granted.

It really seems like you got the bacteria under control. So I'm thinking it could be oxygen. The article I mentioned discussed co2 purity in length.

Oxygen and bacteria are the only things I can think of that would kill a beer that fast.

Thoughts?


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[jdgabbard]

Try bottling some of the beers before you keg just to prove that it is not some infection from fermentation.

This.

It could really be a number of things. Maybe your kegs need a thorough breakdown to be cleaned, maybe you need to clean your lines (tastes from other beers can linger in them), maybe it's your tank that's causing worry. But another could be aluminum oxide in your brew kettle. Having a unique knowledge of beer and wines other, less legal brother, aluminum is shunned for any type of vessel because of this. Along with brass and other non stainless items. You might try a mini batch in a cheap Walmart stainless kettle to see if you still have this problem.


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[stevereno30]

I don't think the keg itself is at fault, or the brew kettle, because the beer sat conditioning in the keg for two weeks without developing any off flavors. Then, two days after tapping (and two days on CO2), it goes from incredible to one dimensional and gross. The keg was cleaned with oxiclean. I filed it 60%, let it sit for an hour, then flipped it and let it sit upside down for an hour. I then ran the cleaner through both the gas in as well as the liquid out. I then filled with iodiphor solution and pushed it through the in and out as well. I then filled the keg itself by siphoning the beer from the fermenter into the gas-filled keg through the liquid out. I purged, then let it sit at room temp for two weeks. At this point, I wanted to try it, so I attached it to my kegerator which had been serving an oktoberfest (every piece of equipment was shared, and I haven't tried the Oktoberfest to check for the same flavor) so I attached my co2, poured and thoroughly enjoyed three pints. The very next day I detected a hint of that off taste, and by the day after that, it's all I could taste and smell. I can't imagine the amount of bacteria that could have been introduced would be substantial. Also, knowing that the beer was in a 50 degree environment AND the beer was poured immediately after tapping (in my mind, any miniscule amount of bacteria left in the lines would have gone into my glass, not the keg), what kind of bacteria can spoil 5 gallons in 30 hours? CO2 seems much more likely since it is being forced into the beer. Just my thought.

 

[winvarin]

1. How do you carb the beer? It sounds like you may be naturally carbing in the keg then using your gas just to dispense. Is this true?

2. If my assumption in #1 is correct and you are using your gas tank only to serve, do you notice that your beers seem over-carbonated once the issue presents itself?

I ask both of these because I am wondering about the age and health of your regulator. I once had a robust porter go from perfect to over-carbed, thin and harsh in about 48 hours. I had a nasty case of pressure creep that didn't show up on my low pressure gauge. So it looked like I was putting 10 psi (at 40F) into my beer. In reality, my regulator was broken and was actually putting more like 20-22 psi into the beer.

I finally diagnosed it by building a makeshift pressure gauge, relief valve (I'd been wanting to do this for awhile because I have a couple of keg lids that do not have a pressure relief on them).

I can post pics later when I get home. But I basically got a little pin valve and a low pressure dial gauge from the gas fittings section of the hardware store. I'd brought a threaded quick connect with me and I just kept matching parts in the gas fittings section until I could go from the keg gas QD, to the pin valve and on to the gauge.

I had to make the last connection with a small piece of gas tubing. But what I have allows me to attach this small device to the gas post of a keg at any time and check the amount of pressure inside. I use it as a second data point when I am trying to determine how much pressure is on the keg.

For the beer I'd over-carbed, my regulator's gauge told me it had 10 psi. The device I built said I had 20-22 psi. And the beer was sharp and over-carbed. As I bonus, I can use the device to bleed pressure off a keg, or completely depressurize it for disassembly when empty.

 

[cele]

I experienced this exact same issue. In fact, reading your description reminds me precisely of the problem I had, even down to the timeframe of a great first poor and awful, undrinkable beer a day or two later. Like you, I cleaned every part of the system extraordinarily well and, after trying two additional kegs and still having the issue, I replaced the CO2. Thankfully, this fixed the problem. I've had four or five kegs through the system now using the new CO2, and I have yet to taste that awful bitter flavor. Of course, I did not isolate each individual variable in the system and so I cannot say for sure that the gas was the problem, but for $20 replacing my 20 pound CO2 tank fixed the issue for me. For what it's worth, I changed nothing else in my process. Incidentally, my CO2 sat in a non-temperature controlled garage for about a year in between the time when I previously used it and when I began having the problem. I don't know if the inside of the tank may have rusted or something else became contaminated (I know that CO2 itself does not go bad),but whatever it was it was linked to the gas. If you can't isolate another problem, I recommend you change the gas.


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[stevereno30]

That is so encouraging to hear. My beers have not been over carbonated, so I doubt the taste comes from too much co2, but as the beer sits at room temp, the taste and smell gets better and better. But of course, then I have warm flat beer. I can't imagine bad taste goes away as beer warms I'm going to try to bleed the keg flat, then get some new co2 to carbonate with. Hopefully these three kegs aren't a list cause!

 

[ChemEng]

It would be interesting to force - carb some DI water with your suspect CO2 in a clean keg to see if the water would pick up the smell/taste.

 

[stevereno30]

It's funny you say that because I emptied, rinsed, filled and hooked up a keg that had been holding nothing but iodiphor to one of my tanks just last night. Not DI, but if that flavor appears in my tap water, I'll know. Thanks for the input!

Edit: After carbonating the water (shake method at 35 PSI), no such bitterness came. It definitely tasted like CO2 water, but the flavor was very different from what I tasted in my beer.

 

[stevereno30]

A new addition to my tale...

I went to my LHBS to get a CO2 exchange, and while there, I brought some of my beers for the employees to try. They tasted it and think my off flavor comes from tannins. They told me that I don't taste the tannins at tap time because the CO2 increases their perceptibility, and as the beer sits on CO2 (and apparently increases in carbonation), the flavor becomes more pronounced. This would explain why the beer tastes better flat than it does carbonated.

Anyway, this would mean my mash procedures are poor, or my chemistry is off. I never approach 170 during the mash, which means my pH must be sky rocketing at the end of the sparge. I bought some 5.2 buffer to help with my apparently bad water chemistry, so we'll see how things turn out in my next brew! As for now, I'm degassing my IPA at room temp, then I'll slowly re-carbonate it at a lower PSI to see if that helps at all. Thanks for your help everyone!

 

[riderkb]

The 5.2 might work on your sparge water, but don't bother puting it in the mash. It is just a blend of phosphate salts and the phosphate will precipitate out your calcium, which might already be in the right range. If you have very hard water then it won't work for you at all.

 

[stevereno30]

Good idea. Is my pH likely to change during the mash? My guess is it would change mostly from the sparge, and that's where tannins would leach. My profile us Minneapolis Water which is pretty nice for beer. If I'm doing a lighter beer like an IPA, I add acid to hit that magic 5.2 pH. What else would cause tannins to leach into my wort other than temp and pH?

 

[MKBoitnott]

If you think your problem is with your water and mash pH. Then I would strongly considering learning all about water and pH and the mash. Invest in the pH meter and all involved.

I recently dragged my way through the Water book and learned a HELL of a lot.

 

[riderkb]

The mash has significant buffering capacity, which works to keep the pH stable. It is when you start washing out the dissolved solids during the spare that the pH starts to change.
I bought one of the cheap pH pens on eBay and it works just fine. $10 and an expected lifespan of two years. Seems like a good deal. The Internet chatter makes it seem like they are popular with hydroponic pot farmers. Is that a good endorsement?

 

[stevereno30]

I have a pH meter, I just never bothered to monitor my sparge. I'll be adding calcium to my next mash (I read it helps with buffering, plus mine is a little low) and I'll be adding 5.2 to my sparge water. I'll probably do something pale so I can taste all off flavors.

 

[muels]

Just drink it all the first day you tap the keg!!!


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[frettfreak]

temps are going to cause excess tannin extraction as well. Make sure your mash and sparge temps are good. FWIW, i have tried (and measured) with and without 5.2 stabilizer in my mash and i dont see it really does anything. YMMV.

What has been your mash and sparging procedures so far?

 

[Riot]

If you have a pH meter already, I would suggest not using 5.2 and instead figuring out how much phosphoric or lactic acid it takes to get your sparge water <6 and not have to deal with the additional salts in 5.2. You will likely need to do some testing but once you have it dialed in you should be great. Take a gallon of water, add .5ml acid and test pH. Shouldn't be hard to adjust from there and increase volumes.

 

[stevereno30]

My mash tennis have remained below 169 just about always (unless doing a decoction mash). I have been adjusting the pH with lactic acid, never adding sparge water with a pH higher than 5.4. I bought the buffer because I figured whatever is happening between adding the acid and collecting the run off can be stabilized with additional help. I'll still be using acidification, but thought the 5.2 would help. Is this overkill? Am I erring somewhere else? Will adding calcium sulfate and calcium chloride help? (all three minerals are on the low side in my water according to brunwater) Thanks for the input!