So I recently got two used corny kegs, about 3 months apart, both from the same place. I cleaned them both very thoroughly - soap, rinse, pbw, rinse, rinse, etc. I also changed all of the o-rings on both of them. I have a new 5lb C02 tank and a new 5ft picnic tap (I think it's food grade PVC) that came with the kit.
I kegged a pumpkin ale back in October, and it always tasted off to me. It seemed like there was this slightly sweet finish to the beer. It was a residual taste that would kind of come in late, maybe a little in the aftertaste as well. My first thought was that maybe I hadn't cleaned the keg as well as I had thought and some soda flavor was still coming through. My other thought was that it was my first attempt at a pumpkin ale, so I figured that maybe the recipe needed more hops or something. The taste bothered me to the point that I set up a taste test. One glass of beer that went through the picnic tap, and another glass of beer that I scooped out of the keg with a measuring cup. The test was inconclusive. I thought maybe the scooped beer didn't have as much of the flavor, but the difference was minimal enough for me to think it was possibly all in my head.
I put filtered H20 in the 2nd keg to make club soda. I was troubled to find that this water also has a very similar airy sweet finish like the beer did. It's really hard to describe the flavor. You wouldn't try it and say "hey, this water is sweet", it's more of a perception of sweetness. And it's not just me who tastes it - the wife does as well.
The only constants between the two kegs have been that I'm using the same CO2 tank, same C02 line, and same picnic tap. The CO2 itself was actually different because I had to get the tank refilled before carbing up the H20 keg. I did get the tank filled at the same place though - but I'm not worried about that because the place specializes in setting up draft systems for restaurants, so the CO2 should be fine.
From what I've gathered from this forum - the taste probably isn't coming from the C02 itself, but I have to ask - does CO2 have an inherent flavor?
Also, is it possible for the C02 tubing to be imparting a flavor?
I'm thinking the picnic tap is the most likely culprit at this point, but even after pouring out half a cup of beer or water that's been sitting in the line, I feel like I can still taste the off flavor. Can an off flavor be imparted just by having the drink pass through the tubing as it's served?
Any help/ideas would be great!