How much O2 does the yeast actually consume in bottle?

[n87]

So after a recent comp (Newcastle), both me and another of my fellow Central Coast Brewers got notes referring to oxidisation.
Now I am aware that the judges dont always know exactly what has caused a particular taste, and they have tasted many beers before yours etc.... And there are plenty of sources for oxidisation, but it has got me thinking, how much O2 is in the headspace, and how much of that does the yeast consume?
There has been a hell of alot of 'The yeast will eat up all the O2 in the headspace, but no 'proof' or sources other than 'ive had an old beer and it was fine' especially on the oxygen scavenging cap threads I have been reading.

I have done some searching and calculating, and i am coming to the conclusion that the yeast really doesnt consume much of the available O2 in the headspace.

Assumptions:
normal fermentation, plenty of yeast left in suspension
using bottle wand to fill bottles to overflowing
bottle wand is 10mm OD (dont have mine here to measure right now)
longneck is 230mm high and 750ml liquid under headspace
Maximum amount of DO from shaking is 8ppm source

Constants used:
O2 = 21% of air
O2 weight = 1.429 kg/L source

Calculations:
h = Headspace = volume of bottle wand
h = 52π x 230
h = 18064.2 mm3 = 18mL
O2h = 21% x h
O2h = 3.78ml = 5.4mg

Much of this will be dissolved into the beer just by being there, but if this was all dissolved in the beer, it would amount to 7.2ppm

Now, that is quite a lot of oxygen, more than I expected tbh.
What I dont know is how much of that oxygen the yeast actually consume. I am under the impression that yeast only consumes oxygen when in growth.

So, the question:
Will yeast consume 7.2ppm O2 in the bottle assuming it was a healthy primary fermentation, bottled after 2-3 weeks and you added 0.008SG in priming sugar?

 

[Adr_0]

I thought exactly that - that very little would be taken up by the yeast, due to the limited growth and potentially already getting all they need during primary or in the starter.

I think most people consider O2 in the bottle headspace only. With the production of CO2 - from broken down glucose, NOT from dissolved O2 - this may reduce the concentration in the headspace due to the extra CO2 molecules there.

In the actual beer itself, would O2 be scrubbed from the beer? I really don't think that's possible.

Could be missing something obvious, but I tend to agree with your conclusion, hence:
http://aussiehomebrewer.com/topic/94128-bottling-oxidation-reduction-trick/?p=1434484

 

[n87]

I thought exactly that - that very little would be taken up by the yeast, due to the limited growth and potentially already getting all they need during primary or in the starter.

I think most people consider O2 in the bottle headspace only. With the production of CO2 - from broken down glucose, NOT from dissolved O2 - this may reduce the concentration in the headspace due to the extra CO2 molecules there.

In the actual beer itself, would O2 be scrubbed from the beer? I really don't think that's possible.

Could be missing something obvious, but I tend to agree with your conclusion, hence:
http://aussiehomebrewer.com/topic/94128-bottling-oxidation-reduction-trick/?p=1434484

I did see that when you posted, purging the bottle helps minimise the oxygen getting in when filling the bottle, but you would need to also have some way of filling the headspace as you remove the tube

 

[Bribie G]

This is one of the reasons I rarely use glass nowadays. The temptation for comp entries is to use Coopers bottles etc. for a "good look" but as per this thread there is going to be a headspace after bottling. Some competitions I have entered have even specified how much headspace is desirable but I don't know if this still applies with any of them.

For a long time now on bottling, I use a bottling wand and standard brewing PETs, and squeeze the sides to elimitate any headspace, until the beer is flush with the surface, then cap.

Obviously the CO2 generated by bottle conditioning restores the shape of the bottle, and the headspace is hopefully fairly pure CO2.

 

[good4whatAlesU]

I usually give the bottle a bit of a 'bump' after removing the filler tube, this pushes C02 filled foam up to the mouth displacing any 02 left in the neck.

In doing so you also lose a slight bit of carbonation, but can be counterbalanced by slightly over carbonating in the first place. A bit of living yeast in the bottle will produce an extra bit of C02 anyway.

 

[Bribie G]

I've just become aware of the other thread about bottle oxygenation that's been necro..d (necroed??)

MHB said at that time that it was a WOFTAM to buy oxygen absorbing caps etc as the bottle conditioning should use up any available oxygen.

Well worth a read rather than re thrashing an interesting discussion from 2010, unless any new results have come in.

 

[Adr_0]

I did see that when you posted, purging the bottle helps minimise the oxygen getting in when filling the bottle, but you would need to also have some way of filling the headspace as you remove the tube

I'm hoping there in enough CO2 around the surface, and the surface area is not a massive amount at that point.

I'm curious if there's a better way, though Bribie did highlight a good way. Most automated bottling lines would not be too different from my method, although I guess a smaller diameter tube is used? That would be help get a more accurate and stable level.

 

[DUANNE]

i used to do the same as bribie with plastic bottles. but i have in the past bottled beer from one batch in plastic and glass bottles. after six months the plastic bottles were an oxidised mess but the glass was still good as the day it was born. it might not prove a great deal but i havent used plastic for anything since then.

 

[kaiserben]

For a long time now on bottling, I use a bottling wand and standard brewing PETs, and squeeze the sides to elimitate any headspace, until the beer is flush with the surface, then cap.

Obviously the CO2 generated by bottle conditioning restores the shape of the bottle, and the headspace is hopefully fairly pure CO2.

How quickly does the shape of the bottle get restored?

When bottling a batch yesterday, the last bottle was only 2/3rds fulI, so I squeezed the headspace and put the cap on. All good there. I went to move the bottles ~36 hours later and the shape of the bottle was back to normal (with the huge headspace due to being only 2/3rds filled).

I was a bit shocked that it'd happened so quickly and immediately thought O2 had got in somehow, but hopefully it's CO2 and the beer will be drinkable.

 

[n87]

Most likely the beer has heated up (assuming you cold crashed) and some of the CO2 breaking out of solution, both helping to equalise pressure.
That along with yeasty farts of course.

Provided the cap was actually put on properly, I would be very sceptical if that amount of O2 would have gotten in.

I would hazard a guess that that bottle will be under carbed when you go to try it. while liquid doesnt compress, gas does. this is one of the reasons headspace size is 'critical'

 

[DJ_L3ThAL]

I'm hoping there in enough CO2 around the surface, and the surface area is not a massive amount at that point.

I'm curious if there's a better way, though Bribie did highlight a good way. Most automated bottling lines would not be too different from my method, although I guess a smaller diameter tube is used? That would be help get a more accurate and stable level.

A lot of modern craft brewers and other beverage packagers are using Liquid Nitrogen droplet dispensing systems in between filling and capping. That is a micro droplet of Liquid Nitrogen is dropped onto the liquid surface which rapidly flashes into Gaseous Nitrogen and inserts the entire headspace as the machine seals the top.

Some "larger" brewers simply drop hot water on top to froth CO2 out of solution to achieve a similar outcome but they are pasteurised beers. Saw that on a brewery tour in Abbotsford VIC [emoji6].

So if they go to those efforts there needs to be a good reason/benefit. I've seen bottle carbonated/conditioned beers still going through this process, so the dissolved O2 is what the yeast use in those cases.

 

[Adr_0]

A lot of modern craft brewers and other beverage packagers are using Liquid Nitrogen droplet dispensing systems in between filling and capping. That is a micro droplet of Liquid Nitrogen is dropped onto the liquid surface which rapidly flashes into Gaseous Nitrogen and inserts the entire headspace as the machine seals the top.

That's awesome.

Well maybe I should jet CO2 in on top of the beer as well?

 

[n87]

https://www.youtube.com/watch?v=SUWBFOnln4k


How hot do you think the water needs to be?
after watching the above video, I figure this could happen with a spray bottle and pre boiled water

 

[Adr_0]

Or some dry ice pellets.

 

[tugger]

I run a rims tube in line with a jet of water at 97c on my commercial bottle filler as said above to produce foam in the neck of the bottle right before the crowner.
I try and aim for under 50 ppb of dissolved oxygen in all beers.
On the can line we use a jet of co2 to fill the headspace with co2 right before the seamer.
On uncarbonated juices and teas in cans I use the liquid nitrogen injection system. It's more about giving the can some pressure over evacuating the head space.
I have a video here showing the hot water jetting process, I need to upload it somewhere so I can post a link to it.

 

[MHB]

Time moves on and we all learn (well some do some don't) in the last 6-7 years I have reached the conclusion that yeast wont do as good a job of scavenging yeast as I thought.
I think it will scavenge O2, but not before the O2 has done measurable oxidative harm, partly due to the point in the life cycle we are packaging at and the time it would take the yeast to wake back up and get to work. Partly because yeast wont wake up unless there is enough sugar available to make it worth while.

Short answer - not enough, too slowly and we should do all we reasonably can to avoid Oxygen uptake at every point in the brewing process (well except obviously when pitching yeast)

A bit of light reading for those so inclined
View attachment Oxygen_11.pdf
View attachment DO in beer IBD.pdf
Mark

 

[DJ_L3ThAL]

https://www.youtube.com/watch?v=SUWBFOnln4k


How hot do you think the water needs to be?
after watching the above video, I figure this could happen with a spray bottle and pre boiled water

Hmm, not like that, I mean a droplet placed directly into the liquid, that looks more like it cleans the surface of the crown seal and outside of the bottle. These bottles passed on the conveyor for a few seconds before being capped too at the "Abbotsford" brewery, foam slightly spilled out the top.

Or some dry ice pellets.

You'd want to be damn sure it has flashed off so that you didn't over-pressurise the head space and end up with a bottle bomb. Few seconds probably but thought it prudent to mention in case someone capped a stubby after reading this with a partially sublimed pellet still in the neck.

 

[n87]

Hmm, not like that, I mean a droplet placed directly into the liquid, that looks more like it cleans the surface of the crown seal and outside of the bottle. These bottles passed on the conveyor for a few seconds before being capped too at the "Abbotsford" brewery, foam slightly spilled out the top.

The caption to that movie :
"Injection of hot water, for the creation of the foam.
in this way the oxygen present in the filled bottle, is evacuated while the bottle is in the closed"

While a little broken in English.... suggests it is for the same ends.

My guess is that given that bottle is obviously isn't already carbonated, it needs a little more motivation to let go of its CO2