Closed transfer and bottling - are they mutually exclusive?

[Wynne]

In commercial environments you’ll find they cap on foam. The flow is controlled to fill gently with a splash at the end to create the foam. I agree - what is the point of purging the bottle with co2 when you’re going to purge it with beer.
Withdrawing the wand draws in air - displace it with foam, or if you are going for co2 purge do it at this point.

In a well-run, commercial environment bottles are purged with CO2 once or twice before filling against CO2 counter-pressure then, as you say, deliberately, the bottles are then “fobbed” to create foam to cap on. This gives very low levels of in package oxygen and means that most in-pack staling is from other causes. Canning is similar but open cans aren’t mechanically strong enough to use counter-pressure so CO2 is blown over the surface of the beer before the lid is fitted. In each case, it is usually filtered beer from which the yeast has been removed that is being packaged.

When bottling bottle-conditioned beer, up to now, I have relied on the SO2 generated during fermentation and reducing power of the yeast to protected the beer from oxidation but the video and photos earlier in the thread make me wonder whether this is sufficient. When using corny kegs I ferment under pressure and use the CO2 generated during fermentation to flush the serving keg.

 

[JockyBrewer]

The biggest single improvement I've found in avoiding bottle oxidation was to make sure I was capping on foam. To do that means you need a bit of carbonation in the beer.

Obviously if you have kegs and CO2 it's easy. Without you will either need to have a pressure capable fermenter that you can spund in, or transfer to a secondary vessel (e.g. budget plastic keg) that you can partially carbonate in (and potentially dry hop too).

Then you bottle (with more sugar if you want), letting the foam purge the headspace and capping over that. That will get you 95% of the way there.


When I got kegs I bought a fancy Tapcooler bottle filler, letting me purge bottles with CO2 before filling from the keezer tap. Honestly though it works no better and ends up more messy than just filling a bottle using a party tap and capping on foam.

 

[MickDundee]

I’ve kegged a NEIPA this morning, and had enough left to fill a 1.5L growler.

All I did to fill the growler was take the disconnect off one end of the line and stick it down the bottom of the growler. I added a spoonful of sugar to finish the carbonation off and capped on foam. In a few weeks time I will compare the two and see if there’s been any noticeable effect.

 

[Wynne]

In a commercial context, where beer has been filtered to remove yeast, bottles are evacuated and purged with CO2, usually, twice then filled against CO2 counter-pressure, “snifted” to allow a controlled release of counter-pressure, fobbed to produce foam then capped. Commercial brewers take a lot of trouble to avoid oxidative staling of beer in-pack but, generally, filtered beer contains no residual yeast to consume in-pack oxygen.
Personally, I have never bothered with purging bottles with CO2 (unlike kegs) and I’ve never noticed any staling of my bottle-conditioned beers but the dramatic examples of changes to heavily-hopped, NEIPA style beers, shown or linked in this thread, makes me wonder if I’ve been too gung-ho.
What are other folks experience of beer oxidation/staling?
Are heavily-hopped, cloudy style beers particularly vulnerable?
Does anyone have experience to share of using ascorbic acid as an antioxidant?

 

[JockyBrewer]

Heavily hopped beers are certainly the most vulnerable, but any beer benefits from avoiding oxidation, except perhaps certain stouts.

In a commercial environment the brewer will be aware that their beer might not be treated too well between leaving the brewery and being drunk, so they do what they can to prolong the life and freshness of the beer.

 

[An Ankoù]

Quick edit to say that I'll be revising that amount down .

At dry hop: Ascorbic acid (vitamin C) 0.72g per litre of head space mixed with the hops and added to wort
= 10g for a 14 litre headspace on a 21 litre batch in a 35 litre fermenter

This is based on worst case scenario for the amount of oxygen introduced at dry hop and should leave some left over to scavenge oxygen at bottling.

Anna

(the science bit for the calculation:

This paper goes some way to explain why the idea of bottle priming consuming the oxygen through fermentation is a bit of a myth - as is empirically demonstrated in the experiment shown in the video earlier on this thread. It also shows how ascorbic acid is consumed faster and before the earlier antioxidants naturally occurring in beer such as from hops, so protects over a short time. Notably copper trace elements catalyse this reaction, which is of benefit rather than a problem as erroneously reported on another forum as ascorbic acid accelerating oxidation. The evidence is that the ascorbic acid is oxidised faster with copper trace element but ahead of other natural antioxidants.
http://pdfs.semanticscholar.org/0cf0/53f6b4f7d88d576eda3ae0ca65a927a91d90.pdfThe oxygen in the headspace is consumed through oxidation within a few minutes (less than 10) far before fermentation could consume it over a few days.
Also that 10 to 50 molecules of oxygen are consumed for each molecule of ascorbic acid.

This paper makes the case for flavour stability with vitamin C added to cooled wort at 30mg/l
https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.2007.tb00252.x
Balancing this with the merit of oxygen at the initial pitch on the exponential growth phase of yeast, and that flavour stability is sought with the final beer rather than initial wort, the time for addition for most benefit would be at dry hopping.

At dry hop: Ascorbic acid 0.72g per litre of head space mixed with the hops and added to wort
= 10g for a 14 litre headspace on a 21 litre batch in a 35 litre fermenter
This is based on 14 litres headspace at 1 bar (standard atmospheric pressure) having 0.574 mol of ideal gas at 20 deg C
https://www.omnicalculator.com/physics/ideal-gas-lawIf at the time of dry hopping all the headspace were replaced by air as the worst case scenario at oxygen 21% would mean
7.264 x10^22 molecules of oxygen, which would require a 10th to a 50th of the same number of molecules of ascorbic acid to consume the oxygen. With the mole mass of ascorbic acid of 176.12g/mol that translates to 10 to 2 g of ascorbic acid (0.72 g per litre of headspace at most). While the amount of air will increase at lower temperature, it is a relatively small change in density at the range of fermenting temperatures (translating to a difference of 0.07g for air at 10 deg C) so the temperature difference can be effectively disregarded for the air temperature.

Based on 99.8% purity of purchasable ascorbic acid the mass to be added can be taken without adjustment for fillers:
https://www.intralabs.co.uk/ascorbi...qdsAUAsCNrAtzsI5twdEW_-OU7sxvq4RoCbWgQAvD_BwE)

Hi Anna,
I read this with interest in the thread about brewing an IPA to last. I had thought of using ascorbic acid some time ago, bought the stuff and then read somewhere that it had to be used in the presence of sulphur dioxide or sodium metabisulphite, and that the effects were unpredictable and it could actually promote oxidation. I wish I could find that stuff to look at it again.
Anyway, I'm going to give your method a go as the contents of the Paper 1 seem to confirm my original feelings, and its got brewers' input in there. I'm going to go with the maths and add 0.72g per litre of headspace at the time of racking into secondary fermentation. I'll do any dry hopping at this time, too, instead of leaving it until fermentation has finished. One question. the paper says a trace of copper is necessary to catalise the reaction and the experiment uses 0.4 mg Cu++ ions per litre, which seems a massive amouint for a "trace" element. I use a coiled copper pipe immersion chiller and a bit of perforated copper pipe as my hop strainer, which stays in the kettle throughout the boil. I hope to get enough of a trace of copper from those.
Nothing ventured, nothing gained.

 

[Brew_DD2]

I can thoroughly recommend Scott Janish's "The New IPA" book. It has reams of fantastic information on oxidation and novel methods to avoid it.

 

[An Ankoù]

I can thoroughly recommend Scott Janish's "The New IPA" book. It has reams of fantastic information on oxidation and novel methods to avoid it.

I've got the book. I'll give it another look. Thanks.

 

[DocAnna]

Hi Anna,
I read this with interest in the thread about brewing an IPA to last. I had thought of using ascorbic acid some time ago, bought the stuff and then read somewhere that it had to be used in the presence of sulphur dioxide or sodium metabisulphite, and that the effects were unpredictable and it could actually promote oxidation. I wish I could find that stuff to look at it again.
Anyway, I'm going to give your method a go as the contents of the Paper 1 seem to confirm my original feelings, and its got brewers' input in there. I'm going to go with the maths and add 0.72g per litre of headspace at the time of racking into secondary fermentation. I'll do any dry hopping at this time, too, instead of leaving it until fermentation has finished. One question. the paper says a trace of copper is necessary to catalise the reaction and the experiment uses 0.4 mg Cu++ ions per litre, which seems a massive amouint for a "trace" element. I use a coiled copper pipe immersion chiller and a bit of perforated copper pipe as my hop strainer, which stays in the kettle throughout the boil. I hope to get enough of a trace of copper from those.
Nothing ventured, nothing gained.

Table III in that first paper shows that the copper content even at much lower levels still catalyses the reaction with ascorbic acid but just a bit slower. As for copper being present, hops contain copper at varying levels so you are adding copper exactly at the time of dry hopping that would accelerate oxidation, which goes some way to explain why heavily hopped beers are more prone to oxidation:
https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.2050-0416.1954.tb02781.x
Also final levels of copper in commercial beers while low are still relevant as shown in this paper on copper levels in European beers: https://www.researchgate.net/figure/Cu-concentrations-mg-L-for-the-investigated-beers_tbl2_315844057

As copper in this case is acting as a catalyst, and at the high levels the oxygen was consumed in minutes, it seems no bad thing at all if the level in our beer is lower than 0.4mg/litre.

Anna

 

[An Ankoù]

Thanks @DocAnna and @Brew_DD2. I'll give all this material a good looking at with new eyes over the next few days.