Strange Rubber taste after using "old" CO2

I kegged up a very nice English IPA last week. Have been primarily bottling for the last 5 years, but decided to keg this batch. I had an old tank of CO2 I got from a friend, probably 10 years old.

After contacting the local HBS folks and researching a bit on the net it seemed the consensus was that CO2 will not go "bad" and it would be safe to use. I tried a sample after racking into the corni-kega and was very happy with the results. Well after about 4 hours of forced carb at 13 psi I decided to try the brew and see how it was coming along. Immediately I noticed an off flavor. The next day I tried again, the carbonation was good but same off note. Had a friend try the beer as well and he agreed.

After trying to figure out the flavor I am thinking it tastes like rubber - possibly gasket or o-ring. It may be true that the CO2 will still be CO2 in its molecular form, wondering if something in contact with the CO2 was degraded over time imparting this aweful after taste. Any thoughts would be welcome.

Welcome to HBT!

Yes, your LHBS is correct - CO2 doesn't "go bad". In your scenario, I can think of a couple of possibilities:

1. The CO2 bottle wasn't properly evacuated before filling, leaving some contaminated air in the bottle.
2. The CO2 pump used to fill the bottle was failing (e.g. worn seals) at the time of the fill.
3. The "rubber" off-flavor was already present in the your beer and the escaped CO2 allowed the aromatics to become detectable.

I didn't see anything in the OP about how new the kegging equipment is, aside from the CO2 tank. If the beer lines are new, that could be your culprit. I had the same concern when first kegging; was given an old tank with CO2 in it and was worried the air inside was "bad." However, after the first several pints it started to fade so I deduced it was the beer line and after an oxyclean soak and sanitizer, the rubber taste went away.

Well that was a thought, and yes it is brand new clear beer supply line from the HBS. I think I rinsed it, but not really a good sanitizing soak. The corni keg and fittings were cleaned well and sanitized prior to transfer. I have never had a "rubber" off flavor before in nearly 15 years of brewing - although that doesnt mean it did or will happen. I will look into the hose issue and clean it well and give it a try. I have only poured maybe a pint so far. Would be great if my beer is still "good" and not ruined due to a bad bottle of CO2.
Thanks for both of your responses and any others that follow.

Ripbeer said:

Well that was a thought, and yes it is brand new clear beer supply line from the HBS. I think I rinsed it, but not really a good sanitizing soak.

Thanks for both of your responses and any others that follow.

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First of all, you're welcome =)

Secondly, a sanitizing soak alone won't do much to eliminate the rubbery taste. Get some Oxyclean-Free or the $2 stuff from Wally World and really let the line soak (completely, inside and out) for 30-60 minutes in a hot oxyclean bath; you can do longer if you'd like but best probably not to exceed a couple hours. Some of my 3/8" racking lines are super cloudy now because of too-long soak. Then rinse the living Bejesus out of it to make sure all of the oxyclean is off. Then soak it in your favorite sanitizer.

I removed the old stuff I was using, it was red line, same as I used for the air, but was pretty fouled after 5 years of sitting so opted for the new clear line...never had the issue with the red line stuff...guessing the clear line is vinyl tubing? Oxy clean it is...hope that takes care of the problem.
Steve

If the clear beer line can impart this off flavor woundnt everybody using it be having this issue ??? I figured since I purchased it from a very reputable high end LHBS (F. H. Steinbarts) there would not be any need of "special" preparation, or at least they should mention it upon purchase....oh well, just want my beer back.

Ripbeer said:

If the clear beer line can impart this off flavor woundnt everybody using it be having this issue ???

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Some people say they can taste "plastic/rubber" if the beer sits in clear vinyl line for an extended period of time (e.g., 2 hours). If your line of reasonable length (less than 10ft), it's only a couple of ounces which I don't believe is detectable by 99% of beer drinkers.

However, I can certainly see this being more of a problem in long line runs (e.g., 20+ft). They manufacturer specially lined PET-vinyl tubing that is supposed to solve the flavor issue. It's hard to find and pretty expensive, though.

To test this theory on your problem, take an 8 oz sample and pour it out. Then quickly take a 4 oz sample and taste it. If the plastic taste is still there, the problem is not in the line.

It is 5ft of 1/4" ID line I believe so barely 0.25 onces in that run. I will mess around with the line and clean it. probably open up the keg and grab a sample too to see if the taste is present prior to entering the tubing. If so, I guess I will have to assume it was the CO2 or accessory (tank, regulator etc..), or other carbon based compound formed or now detected. Crap. Oh, well, I have a dozen recipes I have made up and are ready to brew up.

Well I did soak and clean the hose in hot water for about 45 minutes and gave long rinse. The beer is perfectly carbonated and it seems for the most part the rubbery off flavor has either "aged" itself into the brew or the freshly cleaned tubing made the difference. Guess in the future the note to self is to soak any new discharge tubing in cleaning solution prior to using or at least this type. Never had this issue in the past so a bit strange. Thanks for the replies.