Test Results from Bottling using Oxygen scavenging caps and reduced headspace in bottles

[foxy]

This is a beer I posted on what are you drinking about a week or so ago, it is a Sierra Nevada Pale Ale clone. I have checked, and the brew day was 22 December 2020. Dry hops were only 25 gram but the beer still tastes fresh and hoppy.
From my experience if bottling is done carefully it takes a long time to oxidise, presuming it isn't moved around and the temperature stays below 20 C. One I made took two and a half years before I started getting any sherry like flavours. I also fill my bottles to the level of displacement of the wand.

 

[Agentgonzo]

@Neale, @foxy - what temperature did these beers get stored at? Storing them cold helps slow the rate of oxidation, but isn't something that's practical for me, so they just live in the garage.

 

[foxy]

@Neale, @foxy - what temperature did these beers get stored at? Storing them cold helps slow the rate of oxidation, but isn't something that's practical for me, so they just live in the garage.

I store and condition mine on the fermenting room floor which is around 15C

 

[Neale]

what temperature did these beers get stored at?

Once conditioned I store all my bottles at around 6°C. I have a fridge in the garage converted to allow for temperature control for fermentation, so all my bottles go in there between brew days.

 

[chthon]

Just tasted this weeks two beers that were brewed 12 and 13 months ago, bottled. One a light and spicy tripel, the other a wheat beer. No colorisation, no bad tastes.

I bottle from a bucket, which means I need to rack my beer first into it. But I keep the ends of the racking tube and the bottle filler tube always as deep as possible in the liquid.

I also need to store my beers in the garage. But they are placed close to the ground, and on warm days I can open the garage door a little bit so that the temperatures are a bit suppressed.

 

[Neale]

Some time ago I did some tests to see if using oxygen scavenging caps made any perceivable difference to a NEIPA and then to a session IPA or if just filling very close to the brim is enough. (see above).

Some time after doing these tests I made an IPA and bottled one bottle using a standard cap but filling to approximately 5mm from the top of the bottle with the intention of leaving it for a while to see if any noticeable oxidisation happens.

Well after 279 days in the bottle it looks like the picture below. The bottle has been stored in a fridge for the entire time and when poured it looked like it did when it was bottled. I don't think there are any visual signs of oxidation.

Taste wise, it was brewed using Lallemand Kveik yeast so always had that tangerine taste from the yeast which it still has in abundance and is as I remember it from the other bottles. I think it has probably lost a bit of the hoppy fruitiness that it had when it was younger but thats to be expected after this long.

There are no off flavours that I can detect and certainly no wet cardboard taste and its still a very pleasant beer to drink.

So do we need to use oxygen scavenging caps, maybe, maybe not. I do usually use oxy caps because why not as extra insurance, but it doesn't appear to have had a negative effect on this beer to use standard caps. I think this points again to the easiest way to reduce oxidation in bottled beer is to reduce the headspace.

Another test.....

I have recently made a pale ale with necatron hops. I have bottled three test bottles, two using ascorbic acid, (which I have never used before), and one without ascorbic acid that I will keep as a control sample. I intend on leaving these for a long time to see if there is any difference. I will post the results when I eventually open them. They are all bottled with oxy caps and are all filled to 5mm from the brim so the only thing on test is if the ascorbic acid makes a difference to retaining hops aroma and flavour.

On a side note I have used bottles that are 215ml for these tests, if you need any they came from the Harry Potter studio and originally contained 'Butter Beer', my daughter is a fan. The butter beer is carbonated and the bottles take a standard cap so are ideal for test bottles. You'll need a sweet tooth if you want to drink the butter beer yourself though....

279 day old IPA

 

[Agentgonzo]

Excellent work Neale!
It's good to see how well the beer was protected over such a long period of time.

Your scientific approach has helped us fellow bottlers much more than the Chinese whispers that "conventional wisdom" often turns out to be. It'll be interesting to see what effect the AA has over the long period

 

[Cwrw666]

Can someone explain how oxygen scavenging caps are supposed to work? And how are they packaged? If they come in a plastic bag full of air like ordinary caps I would be very dubious.

 

[The Baron]

Protect your beer against oxidation! These oxygen scavengers have a special liner that absorbs oxygen molecules in the head space of closed bottles. This layer protects your beer from oxidation, it ensures flavour stability and extends shelf life.

 

[Agentgonzo]

They're supposed to be activated when they get wet for the first time. But it sounds very much like snake oil. I've not seen any evidence they are different from normal caps

 

[Neale]

I'm not sure on the science of how they work, and from the few tests that I have done there doesn't seem to be a significant difference compared to standard caps when bottled the same way. But they only cost a few pence more than standard caps so I usually get them if they're available when I order. From GEB its £1.75 for 100 standard caps and £1.94 for Oxy caps.

I'll tend to use the oxy caps for more heavily hopped beers and standard caps for porters and stouts.

They do just come in a plastic bag like standard caps. And my understanding is also that moisture activates them, so when I use them I dip them in sanitiser then put them straight on the bottle.

I haven't brewed a NEIPA since my original test a couple of years ago, maybe I need to brew one again and leave a couple in clear bottles for a year. One with an oxy cap and one with a standard cap, that would show if the oxy caps really make a difference.

 

[Pennine]

It's not too often you come across a thread that changes your process. This one however definitely has.

 

[Agentgonzo]

It's not too often you come across a thread that changes your process. This one however definitely has.

Agreed!

 

[foxy]

I'm not sure on the science of how they work, and from the few tests that I have done there doesn't seem to be a significant difference compared to standard caps when bottled the same way. But they only cost a few pence more than standard caps so I usually get them if they're available when I order. From GEB its £1.75 for 100 standard caps and £1.94 for Oxy caps.

I'll tend to use the oxy caps for more heavily hopped beers and standard caps for porters and stouts.

They do just come in a plastic bag like standard caps. And my understanding is also that moisture activates them, so when I use them I dip them in sanitiser then put them straight on the bottle.

I haven't brewed a NEIPA since my original test a couple of years ago, maybe I need to brew one again and leave a couple in clear bottles for a year. One with an oxy cap and one with a standard cap, that would show if the oxy caps really make a difference.

They don't work, they are no worse or better than the standard caps. Ken Grossman tried them for a while and came to that conclusion.

 

[The Baron]

yes but they really cost no more so why not use them even if its the imaginary magic bullet

 

[foxy]

yes but they really cost no more so why not use them even if its the imaginary magic bullet

I'm not saying not to use them, just that if someone wants to use them all well and good, just not to expect it to be the holy grail of bottle caps.

 

[The Baron]

No I was not meaning that Foxy I was saying the same as you, they are virtually the same price so use them but do not expect them to work as sold in the description

 

[Neale]

It's not too often you come across a thread that changes your process. This one however definitely has.

Thanks, I'm glad to have helped. I figure if there's an easy variable that can be tested then why not.

I'm only 22 brews into my homebrew journey and am learning all the time. The testing of reduced headspace came from suggestion on this forum, it seemed to make sense that it would help reduce oxidation so I tested it.

I would encourage everyone to test things like this out for themselves where possible. There were people on both sides of the argument when it came to bottling with reduced headspace. And I suspect a lot of them had never tried it but still had an opinion. I figure there's only one way to find out if it works....

 

[dad_of_jon]

I have found less oxidation from no longer racking to a bottling bucket, but that leads to more sediment per bottle. I reduce the headspace further by tilting the botte when removing the bottling want as per clints suggestion and that also has led to an improvement.

 

[DocAnna]

Thank you for reactivating this thread. The oxidative effect from the headspace occurs within minutes rather than hours, the darkening may take longer as may the effect on taste as this reflects an oxidation cascade. This is why oxidation caps can't influence the risk of oxidation since the absorption of the oxygen from the cap is too slow. I can't quote the references off the top of my head but they were in the ascorbic acid thread.

@Neale did you purge your bottles with CO2 before filling with a wand ?