Bottle Conditioning and Oxygen

[Superdave]

Disclaimer: I am not doing anything crazy when filling the bottling bucket like splashing it around with a spoon; I am and will continue to be careful about splashing and won't introduce oxygen purposly. However, I wonder if this means that it isn't a big deal if a little bit of oxygen is splashed when starting the siphon, or if a bubble gets trapped in the fill tube or something. Basically, this thinking is helping me RDWHAHB.

So while bottling beer the other day, I was thinking about oxygen getting in there.

If I understand everything correctly:
Bottle conditioning relies on the yeast growing a bit, fermenting the sugar that was added at bottling time.

For the yeast to grow and ferment that sugar, they have to multiply.

The stage in yeast's life cycle where they are multiplying is the aerobic stage.
(Growing and multiplying-aerobic; actually digesting the sugars and fermenting-anaerobic.)

Co2, to some degree, "scrubs" oxygen from the beer.

So it seems to me that the yeast would use up any oxygen that might be introduced at bottling time, a very small amount may be beneficial, and the co2 would help remove any leftover oxygen.

Right? What step am I wrong in my thinking?

 

[Dos_Locos_Brewery]

You're right in the RDWHAHB conclusion that a little oxygen is nothing to worry about, but a couple of the details aren't quite right. Ideally, during carbonation, the yeast is fermenting the priming sugar, not reproducing. So there is no guarantee that they will scavage any accidentally-introduced oxygen, but they do tend to do so.
CO2 doesn't scrub oxygen from beer. If it's dissolved oxygen, the yeast will consume it very quickly if they are in the respiration stage (again, yeast normally would not be in this stage for carbonation). If the CO2 is in the fermenter head space, the active fernentation will have a tendency to flush O2 out the airlock - maybe that's what you mean. That would not apply to carbonation, because that's in a closed system. Anyway, my experience is that oxidation from sloppy handling at bottling time is a non-issue unless you tend to keep the brew a long time. Typically, this is many months, unless you're really sloppy...

 

[ifishsum]

Don't worry too much over it - I always get a little splash when I first start the siphon and suck in a little air when it finishes. Do what you can to minimize it and you will be just fine.

One thing I do seem to do when bottling, is to just set a sanitized cap on top of each bottle after filling. Once I'm done bottling, I'll clean up the bottling bucket and everything before I start crimping down the caps - the idea being to give some time for any CO2 coming out of suspension in the bottles to displace the oxygen out the top before they're sealed up. I don't know whether it really matters, but it does make me feel better.

Honestly I probably drink it all up before oxidization would really show up anyway - it takes time to develop - but I can say that I've never tasted it in my brews. In other words, RDWHAHB!

 

[Pappers_]

If you use a bottling wand, you've got no worries! Cheers