Odd Flavor from 2nd Keg

[lanev]

I kegged up my first batch of homebrew which was an amber ale. I have a 1.75-gallon keg and a 2.5-gallon keg.

My first keg tasted great, however, my second key has an off flavor that I just can't quite place. It's not terrible but not pleasant either. There was probably a month or a little more between tapping the 2 kegs.

I purged the dead space with plenty of CO2. I believe I carefully cleaned both kegs.

I'm sure it would be more helpful if I could place the flavor I'm getting, but any ideas of what I might have done wrong or what I should check to try to narrow down my error?

 

[Dgallo]

I kegged up my first batch of homebrew which was an amber ale. I have a 1.75-gallon keg and a 2.5-gallon keg.

My first keg tasted great, however, my second key has an off flavor that I just can't quite place. It's not terrible but not pleasant either. There was probably a month or a little more between tapping the 2 kegs.

I purged the dead space with plenty of CO2. I believe I carefully cleaned both kegs.

I'm sure it would be more helpful if I could place the flavor I'm getting, but any ideas of what I might have done wrong or what I should check to try to narrow down my error?

Without describing the off flavor no one will be able to guess what it is or tell you what caused it.

Oxidation develops over time so it’s extremely possible (and since you’re new to home brewing, likely) that the older keg oxidized. That being said, even if you cleaned the keg and sterilized it, it’s also extremely possible your beer was infected prior to transferring. This also happens overtime if wild microbes got it.

What was your process for purging the kegs?

What was your process of fermentation and racking into the keg?

 

[VikeMan]

I believe I carefully cleaned both kegs.

You also sanitized them, right?

My first keg tasted great, however, my second key has an off flavor that I just can't quite place.

Try really hard. Or as @Dgallo said, nobody can troubleshoot this.

 

[lanev]

What was your process for purging the kegs?

After I filled and sealed the kegs, I connected the gas in and set PSI to about 20. Let the keg fill and then purged from the keg pressure valve probably 10 times.

What was your process of fermentation and racking into the keg?

Fermentation was in a glass carboy in a temp controlled mini-fridge with airlock filled with sanitizer. It sat for about 4 weeks before using an auto-siphon to move directly to the keg.

You also sanitized them, right?

Yes, used PBW to clean them, let the parts soak for a bit and then let the parts soak in Starsan for a bit as well. Ran Starsan through the kegs just before siphoning the beer to them.

Try really hard. Or as @Dgallo said, nobody can troubleshoot this.

I knew this was a stretch to ask. Sitting here with a little sample, it feels like it lost a lot of the body. I'm hard-pressed to say it tastes bad, just not good anymore. I could drink it, but it would not be enjoyable. It was an amber ale and had nice caramel notes but those almost feel a little fruity to me now.

I have a feeling you'll say it probably oxidized. That would be frustrating considering how many times I purged the dead space and it was still under pressure when I tapped it so I don't think it was leaking or had a bad seal while it sat in the fridge for a month or so.

 

[Dgallo]

After I filled and sealed the kegs, I connected the gas in and set PSI to about 20. Let the keg fill and then purged from the keg pressure valve probably 10 times.




Fermentation was in a glass carboy in a temp controlled mini-fridge with airlock filled with sanitizer. It sat for about 4 weeks before using an auto-siphon to move directly to the keg.




Yes, used PBW to clean them, let the parts soak for a bit and then let the parts soak in Starsan for a bit as well. Ran Starsan through the kegs just before siphoning the beer to them.




I knew this was a stretch to ask. Sitting here with a little sample, it feels like it lost a lot of the body. I'm hard-pressed to say it tastes bad, just not good anymore. I could drink it, but it would not be enjoyable. It was an amber ale and had nice caramel notes but those almost feel a little fruity to me now.

I have a feeling you'll say it probably oxidized. That would be frustrating considering how many times I purged the dead space and it was still under pressure when I tapped it so I don't think it was leaking or had a bad seal while it sat in the fridge for a month or so.

Purging the way you did does not eliminate all the o2. It’s mixes with the co2 you are pressurizing the keg with. I believe it takes nearly 20 purges at 30 psi to eliminate all o2 from the head space. You’re better off filling the entire keg with water and pushing it completely out with the co2 tank, that will completely purge your keg prior to racking into it. Then you should look into connecting your racking cane on a ball lock fitting and then transferring into that closed keg through the liquid post. That will help if it’s oxidation

If you’re losing body there is a high chance it’s an infection. Many wild microbes can process complex sugars which would cause a thinning of the beer’s body

 

[VikeMan]

I knew this was a stretch to ask. Sitting here with a little sample, it feels like it lost a lot of the body. I'm hard-pressed to say it tastes bad, just not good anymore. I could drink it, but it would not be enjoyable. It was an amber ale and had nice caramel notes but those almost feel a little fruity to me now.

"Fruity" could be esters. If they weren't noticeable before, but are now, it could be that some fusel alcohols in the beer have been converted to esters (by yeast) as the beer aged. Fruity can also be a sign of oxidation, especially if it's a "sherry-like" fruity.

ETA: The way to avoid producing excess fusels/esters is to keep fermentation temperatures from getting too high.

 

[VikeMan]

You’re better off filling the entire keg with water and pushing it completely out either the co2, that will completely purge your keg prior to racking into it

...except for the O2 dissolved in the water left in the bottom of the keg. And there is some. I bet @Die_Beerery knows how much.

 

[Dgallo]

...except for the O2 dissolved in the water left in the bottom of the keg. And there is some. I bet @Die_Beerery knows how much.

Turn the keg upside down and blow it out of the pressure relief valve. No more water

 

[VikeMan]

Turn the keg upside down and blow it out of the pressure relief valve. No more water

Thinking about the way a corny keg, the lid, and the PRV are configured, I'm curious about whether that would remove all the water. Have you by any chance done this and then looked inside?

 

[Dgallo]

Thinking about the way a corny keg, the lid, and the PRV are configured, I'm curious about whether that would remove all the water. Have you by any chance done this and then looked inside?

Water shoots out but never checked if is completely gone because it’s always done before a beer goes in but I could give it a chance tonight with an empty keg and throw a cup of water in the keg and blow it out the prv to see if any is left. Will report back later.

 

[Die_Beerery]

...except for the O2 dissolved in the water left in the bottom of the keg. And there is some. I bet @Die_Beerery knows how much.

I do, but science doesn't apply to homebrewers.