I've been trying to resolve an issue with a flavor in my beers I dislike for some time now. I've had a number of people taste my beers and the results have been inconclusive. I don't want to call it an "off flavor", because, from what I know, it's not one of the typical off flavors discussed in brewing. I changed a number of things in my process for this past brew. I sampled the beer after slowly force carbing for a week and I didn't notice the dislikeable flavor. If it was there at all, it was not noticeable. I'm drinking it now after another week or so of being on tap and I'm starting to get the flavor again. I assume it will only get worse from here.

Are there different grades of CO2? I get my tank filled at a welding supply shop. I'm wondering if this could be the issue. It seems the hops are much less prevalent now as well, although I suppose that could be because the first pull had some of the hop matter in suspension.

Thanks in advance.

I've asked this question before and gotten the answer that CO2 is CO2 - Still I've always wondered because the place I get my gas from doesn't fill tanks they just exchange them. I've got some pretty rusty beaten up tanks from them and i've wondered what the inside must look like


Still - The biggest problem that I found in my process and the cause of the metallic flavor in my beer was that i wasn't purging my kegs with gas before filling them

I stated doing that and have notice a big difference, now if I could just get my water sorted out...

I think Blowmax pretty well addressed it. CO2 is CO2, but a crappy tank could certainly impart something off into the keg. If you are exchanging tanks, I would see what other options are available in a gas supplier. Where in Philly are you? Keystone Homebrew does tank exchanges for $17.

If you have your own good tank that is being refilled, I would look into other variables. Certainly starting with a purged tank before you begin filling it is paramount.

Good luck.

I bought a brand new tank when I switched to kegging so I refuse to do the exchange thing. I don't purge my keg before filling. I siphon my beer into it, seal it up, and then purge the O2/air out, replacing it with CO2. Is this not acceptable?

I've been looking at other variables for probably a couple years now... :\

Your beer is coming into contact with oxygen, then. Though it's not for a long time, it's still being introduced into the environment - try purging. Once the keg is clean and sanitized, seal it and hit it with 10-15 lbs, release the relief valve a couple of times, then de pressurize, remove the lid and fill her up. Try a few like that and see if it helps.

Also, what pressure do you keep them under for serving? You can over carb which will change some of the flavor profile.

I get my CO2 from a welding shop. I have never noticed any off flavors associated with it. They fill my tank while I wait. Up until yesterday, my process when kegging was to not purge the keg with CO2 prior to filling. It didn't seem to have any impact on flavor stability. When I kegged last night, I remembered to purge before filling. I guess we'll see if it makes a difference.

you need to purge, when kegging I hook up a line out fitting to one of my co2 hoses and connect that to the out port pushing c02 to the bottom,, c02 is heavier than 02 so it fill the corny from bottom to top,, then siphon beer in then purge again and pressurize and purge again just for sure

The easiest way I have found to purge the keg (and know that I have all the O2 out) is to fill the keg with starsan, purge the minimal head space, then push the starsan out of the tap with CO2. In the end, I have a santized and CO2 filled keg ready for filling.