I've been having some racking issues lately, I can't seem to get a steady flow through the cane and tubing. Would the bubbles or air gaps that I see in the tubing cause oxidation?
Moving forward, I'm going to get an auto-siphon, but just curious for past brews.
Edit, yes it's definitely air, I cracked the cane recently, so it's getting in through there. Definitely time for a new one, was just wondering how much damage it was causing.
Check all your connections to make sure they are tight. I've had problems at the connection point between the tube and the spigot coming off of the bucket, but the spigot had varying widths as it went up so I just shoved the tube on a little farther and it solved the problem. If you heat the tube up a little in some warm water, it will become more malleable and easier to get a tighter fit.
However, are you sure it is actually air getting into the tube? There is dissolved CO2 in the beer during the racking process, though far less than after the beer has finished carbonating. But it may be enough that when the beer gets pushed through the tube, the CO2 comes out of solution and looks like air getting into the tube.
If it is just CO2, it won't hurt the beer of course. A small amount of O2 probably wouldn't be too noticeable unless you plan to age the beer and really want an purely O2 free environment. Since the beer isn't hot, oxidation takes some time and you will probably ok.
If what you're getting is really air and not CO2, then yes, it can be a real oxidation issue. It's happened to me and I've tasted it in other people's beers. As has already been stated, check your connections to be certain that there are no leaks there. I've found that you can ofter clear the bubbles out of the line by pinching the tubing behind the bubbles, right where the tubing connects to the racking cane. You can also try putting a hose clamp at the tubing/racking cane junction to seal it and prevent air from getting in.
I wouldn't worry about this.
You should probably try and minimize all the leaks in your bottling system, butI don't think this will really affect the quality or longevity of your beer to any great extent. I use a racking cane poked into tube which is not the best fit and I have never experienced off-flavours consistent with oxidation. My (untested) explanation is that not much extra oxygen gets dissoved into the wort, and any that does gets scrubbed out by the CO2 from bottle-conditioning.
