Oxidation During Bottling

[violinguy]

There's a thread up in the beginners forum (where I spend most of my time ) that deals with oxidation. When I bottle, I usually fill 3 or 4 bottles, then cap them. Then fill a few more, then cap, and so on...

In the few minutes before I cap them, am I letting in too much O2? Should I be filling and capping one at a time? I haven't noticed the normal oxidized beer off-flavor, but my palate isn't as refined as many of the experts here.

 

[Gravity]

There's a thread up in the beginners forum (where I spend most of my time ) that deals with oxidation. When I bottle, I usually fill 3 or 4 bottles, then cap them. Then fill a few more, then cap, and so on...

In the few minutes before I cap them, am I letting in too much O2? Should I be filling and capping one at a time? I haven't noticed the normal oxidized beer off-flavor, but my palate isn't as refined as many of the experts here.

Most people cap this way, you're fine

If you're leaving the bottle uncapped for a long period of time, then thats a different story.

Oxidation happens more when beer is splashed around or when it has O2 introduced to it (think creating bubbles from mixing quickly or something) a coupe of minutes in between caps is cool

 

[Sbe2]

It happens when bottling unfortunately. My IPAs fade quickly. For my process I fill one bottle, place a cap on it while filling the next, until I have three with caps on them. Once I have three, I crimp them and repeat.

 

[ncbrewer]

I've read several places that it's good to wait several minutes after placing the caps on the bottles before crimping the caps. Supposedly, it lets escaping and newly formed CO2 push oxygen out. This is one source: https://en.wikibooks.org/wiki/Brewing/Bottling_and_Kegging
I can't confirm this, but it's what I do, and I'm happy with it.

 

[eadavis80]

I fill 12, cap 12 and repeat 4 more times. Never really worried about it honestly.

 

[doug293cz]

If you fill a bottle with a bottling wand to overflow, and then withdraw the wand, the resulting headspace will be 100% air (21% O2.) This will be the same whether you pre-purged the bottle with CO2 or not. The only thing pre-purging accomplishes is reducing the amount of O2 that gets picked up (dissolved in the beer) due to agitation during the filling operation itself. The headspace is all air.

Let's say your bottle has 12 oz of beer and 1 oz of headspace. As fermented beer has about 0.8 volumes of residual CO2, so to get 2.5 volumes, you add enough priming sugar to create 1.7 volumes of CO2. 1.7 volumes times 13 oz (have to "carbonate the headspace too) is 22.1 oz of CO2 at atmospheric pressure. This CO2 gets generated over at least two weeks, or 336 hours. Thus the average rate of CO2 production is somewhere around 22.1 / 336 = 0.06 oz/hr. You're not going to displace much of the air in the bottle headspace with newly generated CO2, by waiting to crimp the caps.

Commercial breweries bottle beer that is already carbonated, so the beer foams a bit during the fill. They then cap quickly on top of the foam (which is CO2 filled bubbles), so that they don't have the air filled headspace problem when capping.

The O2 in the headspace will absorb into the beer over time, and will eventually cause oxidation. The yeast action during carbonation mitigates the O2 presence by forming benign (non-oxidizing) compounds as a result of the yeast metabolism. Ideally, the yeast metabolism would consume all of the free O2, and thus minimize subsequent oxidation of the beer. I don't know the degree to which this actually occurs.

Brew on

 

[mabrungard]

There was a presentation by Bob Hall and Andy Mitchell at the 2017 Homebrew Con that included a discussion on measured O2 levels in bottled beers. Andy is a brewer at New Belgium and he has access to high-tech headspace testers. They were able to prove that a careful homebrewer using a CO2-flushing rig like a counter-pressure filler or beergun can achieve O2 ingress that is actually lower than a high-speed brewery bottle filler can achieve. (I guess they can't achieve perfection at 700 bottles per min!!).

The strong recommendation was that we do need to CO2 purge and cap on foam to achieve low O2 packaging.

 

[kh54s10]

I always fill a bottle, place a cap on top, fill another put a cap on top, repeat this 48-56 times then crimp them all. I have never detected any off flavor.

I think any oxidation problem comes before letting the bottle sit. Like oxygen getting in at transfer to the bottling bucket or a leak in the bottling wand set up.

 

[Hoppy2bmerry]

I've read several places that it's good to wait several minutes after placing the caps on the bottles before crimping the caps. Supposedly, it lets escaping and newly formed CO2 push oxygen out. This is one source: https://en.wikibooks.org/wiki/Brewing/Bottling_and_Kegging
I can't confirm this, but it's what I do, and I'm happy with it.

This makes sense CO2 in solution is being released from the beer.

 

[ncbrewer]

You're not going to displace much of the air in the bottle headspace with newly generated CO2, by waiting to crimp the caps.

Very interesting. I've always had my doubts about getting any appreciable amount of CO2 being generated during this waiting period, but never did the math. But this small amount, plus any off-gassing, might be significant. Either way, I think it's safe to say no more oxygen is getting into the bottle as it waits since there's no negative pressure to draw it in. So it seems that waiting and crimping a whole case or two at a time should be fine.

 

[Smellyglove]

I only bottle beers which are supposed to be yeasty, rest if CFP. But, I carbonate them with speise using a dosage syringe, so I can have close to zero headspace.

Then maybe it's not dumb (haven't tested, but havent had any problems with oxidation either this way) to store the bottle flat for the first few days so the yeast have greater access to the oxygen, thus consuming it faster, and then store the bottles upright.

 

[Epos7]

There was a presentation by Bob Hall and Andy Mitchell at the 2017 Homebrew Con that included a discussion on measured O2 levels in bottled beers. Andy is a brewer at New Belgium and he has access to high-tech headspace testers. They were able to prove that a careful homebrewer using a CO2-flushing rig like a counter-pressure filler or beergun can achieve O2 ingress that is actually lower than a high-speed brewery bottle filler can achieve. (I guess they can't achieve perfection at 700 bottles per min!!).

The strong recommendation was that we do need to CO2 purge and cap on foam to achieve low O2 packaging.

That's very interesting. I have been bottle priming for about a year, and intend to switch over to kegging at some point in the future. While I don't currently have space for a kegerator, I have been considering buying several kegs and a CO2 tank, and force carbonating then bottling from the keg as you described. The advantages in the interim would be beer staying fresh for longer due to lower oxidation, and beer being ready to drink much sooner. In the long term I'd end up using the kegs and CO2 tank for a kegerator setup. I'm encouraged by this evidence that my beer would indeed stay fresher, and my hoppy beers fade slower, if I were to go this route.