Author Topic: First Time Kegging - Metallic Off-Flavor  (Read 7284 times)

Offline ctownbrewer

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First Time Kegging - Metallic Off-Flavor
« on: February 27, 2012, 10:05:03 AM »
I got a dual-tap kegerator for Christmas, so I brewed 2 beers to test it out. The following is the timeline of events...

- Jan 6 - Brewed Scottish Ale & IPA
- Jan 29 - Disassembled, cleaned, sanitized, reassembled, & filled kegs (also discovered the kegerator had a broken filter dryer, so it wouldn't cool)
- Feb 11 - Began force carbonating kegs at room temp (59 F)
- Feb 23 - Hooked up kegs to new replacement kegerator & cooled to 39 F
- Feb 24 - Turned CO2 back on to serving pressure & drew samples...both beers tasted great
- Feb 25 - Poured pint of each & new metallic off-flavor in aftertaste was present (tried the Scottish Ale out of a bottle & it tasted great, no off-flavor)

The beer was in the kegs for about 4 weeks & the first couple pours were great. It was only after it sat for 24 hours after I turned the gas back on that the off-flavor developed. Can CO2 impart this flavor? It seems like I've isolated the problem to the kegs since the bottled version of the Scottish Ale was great.

Anyone have any ideas to where this metallic aftertaste came from?...Will it fade over time? For what it's worth, it's definitely more prevalent in the Scottish Ale.

Offline morticaixavier

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #1 on: February 27, 2012, 10:11:34 AM »
It could well be slight over carbonation. The carbonic bite can taste kind of metallic or minerally. try dumping presure from the kegs then shake the kegs and dump again repeat a few times and check your carb level then once it's down taste the beer.

The scottish might well show the problem more as you are expecting a lower carb level and there are less hops to cover it up.
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Offline bluesman

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #2 on: February 27, 2012, 10:28:01 AM »
The other option is to take a sample and decarbonate the beer by stirring until all of the carbonation has evolved. Taste the beer and note any off flavors.
Ron Price

Offline morticaixavier

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #3 on: February 27, 2012, 10:41:58 AM »
The other option is to take a sample and decarbonate the beer by stirring until all of the carbonation has evolved. Taste the beer and note any off flavors.

so much more simple. good idea.
"Creativity is the residue of wasted time"
-A Einstein

"errors are [...] the portals of discovery"
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Offline ctownbrewer

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #4 on: February 27, 2012, 11:42:17 AM »
Thanks for the input. I'll give it a shot.

FYI - I hooked everything up after 11 days on CO2 at room temp & the beers actually seemed a little under-carbonated to me. If the beer isn't finished carbonating, could that create off-flavors as well? I know I probably should have waited the full 2 weeks, but people have said they've had carbonated beer after 1 week. I've heard carbonating at room temp isn't as effective as at colder temps, which would have been ideal if the kegerator worked in the first place.

Offline ctownbrewer

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #5 on: March 02, 2012, 06:19:58 AM »
I think I found the issue. I drew off 3 separate 3 oz samples last night & was planning on stirring until the carbonation was gone. Before I tried that, I tasted each sample.
- The first was horrible...strong metallic flavor & slightly flat from sitting in the lines.
- The second was better, but still had a slight metallic aftertaste.
- The third was great...tasted like the bottled versions.

I'm thinking the 4-5 oz of beer sitting in the lines is the reason for the off-flavor. I also noticed the beer improved when it warmed up a little, so I think the warmest setting on my kegerator is still too cold. I'm planning on contacting the company I got the kegerator from to see if they have instructions on how to adjust the t/stat. I'd prefer the temp to be around 42 F, because the liquid temp is 3.5 F colder than the ambient temp inside the kegerator.

Offline tschmidlin

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #6 on: March 02, 2012, 05:28:26 PM »
Sounds like you need to do a thorough cleaning of the lines.  Take off the kegs and run some BLC or LLC through the lines and taps.  If they don't come clean, replace the plastic bits.  Disassemble the faucets and clean them out too.  A good pbw soak will get the gunk off.

http://morebeer.com/view_product/8898//LLC_Liquid_Line_Cleaner_32_oz
Tom Schmidlin

Offline bluesman

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #7 on: March 02, 2012, 06:47:22 PM »
Sounds like you need to do a thorough cleaning of the lines.  Take off the kegs and run some BLC or LLC through the lines and taps.  If they don't come clean, replace the plastic bits.  Disassemble the faucets and clean them out too.  A good pbw soak will get the gunk off.

http://morebeer.com/view_product/8898//LLC_Liquid_Line_Cleaner_32_oz

+1

Cleaning any residue then a hot PBW soak of all parts including the keg should be done. As Tom indicated, disassembly of all parts should be done in order to properly clean and remove all organic soils from the system. This should take care of your problem.
Ron Price

Offline bo

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #8 on: March 02, 2012, 07:31:23 PM »
I'd put my money on something other than dirty lines. You've only had this kegerator for a couple of months and it's not like it's been left in a hot garage this time of year. .

Offline bluesman

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #9 on: March 02, 2012, 07:36:56 PM »
I'd put my money on something other than dirty lines. You've only had this kegerator for a couple of months and it's not like it's been left in a hot garage this time of year. .

It's really hard to diagnose without looking at it.
Ron Price

Offline bo

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #10 on: March 02, 2012, 07:41:02 PM »
I'd put my money on something other than dirty lines. You've only had this kegerator for a couple of months and it's not like it's been left in a hot garage this time of year. .

It's really hard to diagnose without looking at it.

I agree completely, so why suggest cleaning lines?

Offline bluesman

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #11 on: March 02, 2012, 07:58:03 PM »
I'd put my money on something other than dirty lines. You've only had this kegerator for a couple of months and it's not like it's been left in a hot garage this time of year. .

It's really hard to diagnose without looking at it.

I agree completely, so why suggest cleaning lines?

It's an industry standard of practice. Whether or not he has dirty lines he should clean his system, and it will also eliminate that variable. It's a process of elimination at this point.
Ron Price

Offline tschmidlin

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #12 on: March 02, 2012, 08:58:30 PM »
I'd put my money on something other than dirty lines. You've only had this kegerator for a couple of months and it's not like it's been left in a hot garage this time of year. .

It's really hard to diagnose without looking at it.

I agree completely, so why suggest cleaning lines?
Why wouldn't you clean the lines?  A couple of months is plenty of time for some contamination to take hold?  I'd also pull the dip tube and check that out for cleanliness, but that's a bit more invasive and since it is in more than one keg the lines/faucets seem likely.

The fact that it starts bad and gets better in just 6 oz indicates something that is not in the keg but between the keg and the glass.  If you have another suggestion I'd love to hear it.  Dirty lines fits the problem.

The fact that it is a new kegerator and tastes metallic could also mean there is some exposed copper or other reactive metal in the system between the keg and the glass.  You could check that too.
« Last Edit: March 02, 2012, 09:01:39 PM by tschmidlin »
Tom Schmidlin

Offline bo

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #13 on: March 03, 2012, 05:48:37 AM »
I'd put my money on something other than dirty lines. You've only had this kegerator for a couple of months and it's not like it's been left in a hot garage this time of year. .

It's really hard to diagnose without looking at it.

I agree completely, so why suggest cleaning lines?
Why wouldn't you clean the lines?  A couple of months is plenty of time for some contamination to take hold?  I'd also pull the dip tube and check that out for cleanliness, but that's a bit more invasive and since it is in more than one keg the lines/faucets seem likely.

The fact that it starts bad and gets better in just 6 oz indicates something that is not in the keg but between the keg and the glass.  If you have another suggestion I'd love to hear it.  Dirty lines fits the problem.

The fact that it is a new kegerator and tastes metallic could also mean there is some exposed copper or other reactive metal in the system between the keg and the glass.  You could check that too.

That's not actually what he said.


" Feb 24 - Turned CO2 back on to serving pressure & drew samples...both beers tasted great
 Feb 25 - Poured pint of each & new metallic off-flavor in aftertaste was present (tried the Scottish Ale out of a bottle & it tasted great, no off-flavor)"

On the 24th he pulled samples which would have been line contents and they tasted great. My experience with line contamination is that I'll get a slug of bad beer first. After more is poured, the off flavor seems to subside.  It sounds to me like it's coming from directly the keg, but I could be wrong. This is why I always keep a cobra tap line handy for quick, alternate line testing.

Offline bluesman

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Re: First Time Kegging - Metallic Off-Flavor
« Reply #14 on: March 03, 2012, 08:12:14 AM »
The fact that it is a new kegerator and tastes metallic could also mean there is some exposed copper or other reactive metal in the system between the keg and the glass.  You could check that too.

This is another possibility. Reactive metals will leach into a beer that's slightly acidic. That flavor is definitely metallic.

Break down the system piece by piece and inspect for any potential corrosion.
Ron Price