The bane of my homebrewing existence

[CBMbrewer]

I kegged a batch of IPA the Friday before last, about 13 days ago. The kegs have been at 40F under 10psi for the entire time. I Just pulled a pint and it has a fairly distinct flavor of what I understand is carbonic acid, a slightly metallic taste. My beers have always tasted great when bottled and tasted fine when I primed a keg in the past. But whenever I force carb, I get this flavor. This is my first time using the set it and forget it method and I am very disappointed to still have this flavor. I know this can be caused by over carbonation but it seems just right and the beer tastes great otherwise. Is there anything I can do to get rid of this flavor and avoid it in the future?

 

[whitehause]

Have you tried a different place for your co2 fills? I never had that until I got got my co2 filled at a differnt place once, It started getting that mettalic flavor, so I vented the whole co2 and had it refilled.

 

[Pratzie]

^^^ what they said, or when thats kicked, check the keg and diptube for any sign of rust/deterioration.

 

[BreezyBrew]

Just wondering because I have had something similar. Very frustrating! Would you describe the taste as a sour aftertaste, or is it closer to an iron flavor.

Mine is a long lasting sour bitterness.

 

[BigFloyd]

I've seen this right after the beer carbs up but hasn't had a chance to condition much. The one time I had this, it went away in about 10 days.

 

[CBMbrewer]

I would describe the flavor as astringent and slightly metallic, definitely not sour. I have always gotten my tank filled at the same place. I'll try somewhere different next time.

I've seen this right after the beer carbs up but hasn't had a chance to condition much. The one time I had this, it went away in about 10 days.

Did it go away 10 days after it was fully carbed or 10 days after you kegged it?

 

[solbes]

I picked up off flavors from my liquid lines, and then switched to the PET lined. You could always tell a difference between the initial pull and beer that had been flowing. Off flavors are gone now.

But you said it was different with natural priming, so that doesn't make sense.

 

[BigFloyd]

I would describe the flavor as astringent and slightly metallic, definitely not sour. I have always gotten my tank filled at the same place. I'll try somewhere different next time.



Did it go away 10 days after it was fully carbed or 10 days after you kegged it?

10 days after I figured it would be carbed (which is when I first taste-tested it).

 

[LandoLincoln]

Well, you could always pour a glass, stir vigorously to dissipate the CO2 and then taste it and see if the metallic taste is still there.

 

[CBMbrewer]

I'll have to degas a sample tonight and see how it tastes. In the mean time I guess I'll give it time and once my tank is kicked get it filled somewhere different even though co2 should be just that; co2. It strikes me as odd that I have read on several posts that some people will be enjoying their beer only a few days after kegging by shaking the co2 into solution. I also understand that many breweries carbonate their beer overnight and I have never experienced this flavor from a commercial brewery.

 

[Dr. Francois]

To how many volumes of CO2 are you carbing this beer?
What psi?
What keg temp?
How long are your lines?

I'm wondering if it is just excessively carbonated.

 

[chumpsteak]

I used to have this until I started watching how they pour tapped beers at the bar. The beer always comes out very fast and knocks a lot of carb out of solution. This usually results in creamier smoother beer that still has plenty of carb. I used to run 10' of 3/16 line and my pours were slow and full of carbonic bite. I cut all my lines to 5' and now I'm much happier. The pour is much faster and bubbles cascade in all my beers. As long as your glasses are clean you will not build too much head either. I carb to 12 psi also.

 

[CBMbrewer]

I am carbing the beer to 2.3
The psi is set to 10 and the keg is at 40F
The gas line is a little over 2 feet and the beer line is 4 feet
The carbonation seems just right. Good head and visible carbonation. Good mouth feel and no problems with the pour.

 

[Bobby_M]

I would be looking at the sulfate content of your water.

 

[CBMbrewer]

I would be looking at the sulfate content of your water.

I have never had this problem with any bottled batches or when I have primed a keg before. I have been using the same water for every batch. I am pretty sure it is carbonic acid, I just want to know how to get rid of it or prevent it.

 

[edds5p0]

I honestly don't think it's carbonic acid, as any time co2 is dissolved in water, it exists as carbonic acid until it bubbles out.

 

[CBMbrewer]

I honestly don't think it's carbonic acid, as any time co2 is dissolved in water, it exists as carbonic acid until it bubbles out.

So, any thoughts on what it is then?

 

[edds5p0]

Could it be iron? In some municipalities when the fire hydrants are flushed there can be a surge of iron, or perhaps a fitting has rusted

 

[Bobby_M]

I honestly don't think it's carbonic acid, as any time co2 is dissolved in water, it exists as carbonic acid until it bubbles out.

I don't believe this to be true. Most or at least some C02 is simply dissolved into the liquid as CO2 molecules.

I didn't remember where I read that but just found it:

http://www.thuisexperimenteren.nl/science/carbonaatkinetiek/Carbondioxide in water equilibrium.doc

"At equilibrium, only a small fraction (ca. 0.2 - 1%) of the dissolved CO2 is actually converted to H2CO3. Most of the CO2 remains as solvated molecular CO2."

 

[Bobby_M]

I have never had this problem with any bottled batches or when I have primed a keg before. I have been using the same water for every batch. I am pretty sure it is carbonic acid, I just want to know how to get rid of it or prevent it.

One possibility is that your naturally conditioned beers had a lower level of carbonation as it's relatively more difficult to predict ultimate volumes of CO2 in bottle conditioned beers without the proper measuring tool. Another reason a carbonation level variation may exist is that your regulator low side gauge could be reading a few PSI low.

To test if it is carbonic acid, take the now "tainted" beer, pour it into a glass and let it warm up to room temp, then put it in the fridge and bring it back down to 40F and taste it. The warming will drive off carbonic acid and free CO2. If it still tastes funky, I'd start looking at your CO2 source or cleanliness of your gas lines.

To your actual goal of preventing carbonic acid, you can't. It forms as a percentage of dissolved CO2 so you can't have carbonation without carbonic acid and no method of carbonation, natural or forced will change it. There is speculation that methods of speed, rush, burst, or whatever name you want to give to faster methods of force carbing will spike carbonic acid for a short time, that's not relevant because that's not what you've done.

 

[CBMbrewer]

To test if it is carbonic acid, take the now "tainted" beer, pour it into a glass and let it warm up to room temp, then put it in the fridge and bring it back down to 40F and taste it. The warming will drive off carbonic acid and free CO2. If it still tastes funky, I'd start looking at your CO2 source or cleanliness of your gas lines.

To your actual goal of preventing carbonic acid, you can't. It forms as a percentage of dissolved CO2 so you can't have carbonation without carbonic acid and no method of carbonation, natural or forced will change it. There is speculation that methods of speed, rush, burst, or whatever name you want to give to faster methods of force carbing will spike carbonic acid for a short time, that's not relevant because that's not what you've done.

Thanks for all the insight.
Didn't get around to degassing and testing a sample last night but will today. From some things I have read it seems that the carbonic acid taste can be more prominent when the beer is freshly carbonated and hasn't had more time to condition giving some of the H20C3 a chance to be neutralized back into water and carbon. Do you think this could be the case? It also seems that some people are just more sensitive to the flavor, which could be part of my problem. Either way, if a degassed sample tastes fine should I expect to see the flavor go away with some more time?

 

[BreezyBrew]

Thanks for all the insight.
Didn't get around to degassing and testing a sample last night but will today. From some things I have read it seems that the carbonic acid taste can be more prominent when the beer is freshly carbonated and hasn't had more time to condition giving some of the H20C3 a chance to be neutralized back into water and carbon. Do you think this could be the case? It also seems that some people are just more sensitive to the flavor, which could be part of my problem. Either way, if a degassed sample tastes fine should I expect to see the flavor go away with some more time?

Ever get around to trying it?

 

[CBMbrewer]

I know its been a while, but better late then never.
After giving the kegs another week in to condition I pulled a pint and the off flavor is completely gone! The beer is now disappearing very quickly. Glad I brewed 10 gallons of it.
When I primed a keg in the past I didn't encounter this off flavor even when the keg was young. So in the future I think I might just stick to naturally priming my kegs.
Thanks for all the input everyone.

 

[Denny]

I would describe the flavor as astringent and slightly metallic, definitely not sour. I have always gotten my tank filled at the same place. I'll try somewhere different next time.

Astringent is not a flavor.