Oxygenation - oxidisation during wort racking

[Jahfish]

Hi all
I started a brew yesterday and pitched the yeast. Now I realise I'm not happy with the fermenter (lid not a good fit) so need to move the wort into another fermenter. Within 24hours of brewing, am I still in the window where oxygenation is a good thing and I can just pour the whole lot, or am I now needing to reduce any risk of oxidisation by syphoning instead?

 

[JockyBrewer]

If you don't have krausen yet you're probably ok to pour, although you'll have oxygen pick up even siphoning.

 

[Stu]

I've done all kinds of things that should bring oxygenisation into play, however, I've since learned that you can do a transfer.
What I'd suggest is making sure you transfer by "filling" from the bottom. i.e. use a long tube sitting at the bottom of the new vessel rather than opening a tap and aeriating the wort.

 

[Agentgonzo]

Yeast will quite happily mop up any oxygen that's present if the yeast is active.
Double-dropping/moving into a secondary is a common practise where you move the wort from one vessel to another (normally at/towards the end of fermentation), which is way later in the process than where you are. https://en.wikipedia.org/wiki/Brewing_methods#Double_dropping.

It's also quite common for people brewing high ABV beers to also give the wort a second dose of oxygen deliberately on day 2 of the fermentation to encourage more yeast growth/health.

The dropping process has two primary effects on the beer being fermented: the trub that has settled during the first period of fermentation will be left behind, leaving a cleaner beer and a cleaner yeast to crop from the beer for the next fermentation; the second effect is the aeration of the wort, which results in healthy clean yeast growth

 

[RichardM]

Why aren't you happy with the lid of your fermenter?

 

[hoppyscotty]

I'd be inclined to leave it. If the lid is not good you'll be fine during fermentation. As long as the lid is mostly sealed then your o2 pick up will be minimal post fermentation. You'll have a column of CO2 sat on the beer filling the bucket space and though some 02 will diffuse through any gaps in your lid it will be minimal and will take a long time to diffuse into the CO2 headspace and contact your beer so you're pretty safe...certainly preferable than transferring right now. You can infuse too much oxygen in your wort and any residual o2 dissolved in your wort post fermentation will have an impact if it's a beer style that is susceptible to oxidation - the yeast has an aerobic and anaerobic phase so will only use oxygen for a portion of the fermentation. When we're talking oxidation risk we're talking about dissolved oxygen in the parts per billion region, not million, so if you're concerned about oxidation then you really need to be as anal as possible to avoid or minimise to the max any contact with the air.

If you're that worried bout the fit of the lid you could always put cling film over the top then the lid on top so the airlock pierces the cling film.

 

[ARNWD]

so need to move the wort into another fermenter. Within 24hours of brewing, am I still in the window where oxygenation is a good thing and I can just pour the whole lot

It's called "Double Dropping".

See Wikipedia @ Double Dropping for an explanation.

On a seperate note I typically re-oxgenate for the first 48 hours of fermentation, every six hours. More oxygen creates = healthy yeast to complete the fermentation process. No stalled brews.

Oxygen can be introduced at any time during fermentation. It's only after fermentation is completed that oxygen is bad.

 

[foxy]

I would just leave it. For instance, if the lid is not sealed correctly it isn't going to oxidise, if you do decide to transfer to another fermenter any oxygen uptake will be scrubbed by the CO2 when fermentation starts in earnest, but transfer as Stu recommends to hedge your bets. Once yeast has gone into anaerobic respiration it will not return to aerobic respiration, if for some reason it did and oxygen is present and no sugar it will produce acetic acid by consuming the ethanol. But that is highly unlikely.

 

[hoppyscotty]

It's called "Double Dropping".

See Wikipedia @ Double Dropping for an explanation.

On a seperate note I typically re-oxgenate for the first 48 hours of fermentation, every six hours. More oxygen creates = healthy yeast to complete the fermentation process. No stalled brews.

Oxygen can be introduced at any time during fermentation. It's only after fermentation is completed that oxygen is bad.

Not so sure at home brew volumes any additional wort oxygenation is required. The yeast will only 'consume' as much oxygen as it needs and any dissolved oxygen that is not needed will start the process of oxidising the beer and shorten shelf life and suck any flavour and aroma from your beer. Through the mash, sparge, boil and hopstand/whirlpool you're usually increasing dissolved oxygen, then during the transfer to fermenter, especially if you're splashing the wort around a bit, you're getting plenty of oxygen into the wort to support a healthy fermentation. The big commercial breweries will invest big $$$$ in expensive dissolved oxygen meters and measure the DO levels and manage accordingly and calculate the amount of additional oxygen needed, if any, as you're transferring to the fermenter...they'll be getting the levels of DO down to the low PPB by the time the beer is packaged. If you go pumping loads of O2 into your wort assuming the more O2 the better, the chances are you're going to end up with high levels of DO in your packaged beer.

There are tables to enable you to calculate how much O2 to add as you transfer wort to the fermenter but without knowing the exact level of DO that you're starting off with you cannot know within the required precision, how much DO you're going to end up with.

 

[foxy]

Not so sure at home brew volumes any additional wort oxygenation is required. The yeast will only 'consume' as much oxygen as it needs and any dissolved oxygen that is not needed will start the process of oxidising the beer and shorten shelf life and suck any flavour and aroma from your beer. Through the mash, sparge, boil and hopstand/whirlpool you're usually increasing dissolved oxygen, then during the transfer to fermenter, especially if you're splashing the wort around a bit, you're getting plenty of oxygen into the wort to support a healthy fermentation. The big commercial breweries will invest big $$$$ in expensive dissolved oxygen meters and measure the DO levels and manage accordingly and calculate the amount of additional oxygen needed, if any, as you're transferring to the fermenter...they'll be getting the levels of DO down to the low PPB by the time the beer is packaged. If you go pumping loads of O2 into your wort assuming the more O2 the better, the chances are you're going to end up with high levels of DO in your packaged beer.

There are tables to enable you to calculate how much O2 to add as you transfer wort to the fermenter but without knowing the exact level of DO that you're starting off with you cannot know within the required precision, how much DO you're going to end up with.

It isn't really clear what yeast the OP used could be dry yeast not needing any oxygen, also people get confused between oxygenating and aerating, big beers 1,080 could get a second dose after 12 hours, and I wouldn't be doing anymore.
For a big beer, I will do a big starter and not oxygenate/aerate the wort, the yeast is ready to go as soon as it gets acclimatised.

 

[hoppyscotty]

Interested in the difference between oxygenating and aerating...I kind of assume to increase the level of oxygenation (i.e. dissolved oxygen) you aerate....Its dissolved oxygen that is what's important so by aerating are you not increasing oxygenation?

 

[Agentgonzo]

Interested in the difference between oxygenating and aerating...I kind of assume to increase the level of oxygenation (i.e. dissolved oxygen) you aerate....Its dissolved oxygen that is what's important so by aerating are you not increasing oxygenation?

Oxygenating and aerating are basically the same. They both add oxygen to the wort by bubbling a gas through the wort. Aerating uses air. Oxygen uses pure oxygen. You can get more dissolved oxygen into the beer by using oxygen, but they basically the same.

 

[foxy]

Interested in the difference between oxygenating and aerating...I kind of assume to increase the level of oxygenation (i.e. dissolved oxygen) you aerate....Its dissolved oxygen that is what's important so by aerating are you not increasing oxygenation?

Aerating is shaking the wort or using an air pump, oxygenating is using pure oxygen through a stone, oxygen doesn't stay in wort too long that is why I prefer to do a big starter on a stir plate over 3 or 4 days. Plus its cheaper than buying oxygen.

 

[Agentgonzo]

the yeast has an aerobic and anaerobic phase so will only use oxygen for a portion of the fermentation

This is a oversimplification and a common misconception. The yeast lifecycle that we read about has the lag/growth phase (aerobic) and the fermentation phase (anaerobic), but these are vast generalisations and simplifications of a very complex biological organism (if we took it at face value, the fermentation phase would "only" produce alcohol, and not lots of the lovely flavour compounds like phenols/esters etc that give beer its delicious flavour).

Whilst fermentation (which is different to anaerobic respiration and confused by beginners) is indeed anaerobic, there are many other metabolic pathways in the yeast which includes consumption of oxygen (eg, during the biosynthesis of ergosterols). So whilst oxygen is not consumed as a part of fermentation, it is consumed by the yeast at the same (but for a different reason) if the yeast requires it.

The yeast will only 'consume' as much oxygen as it needs and any dissolved oxygen that is not needed will start the process of oxidising the beer and shorten shelf life and suck any flavour and aroma from your beer.

True. And over-oxygenation can be an issue. But in reality it is not possible over-oxygenate the wort using air alone (unless you are continuously aerating, which we're not) - you'd have to inject pure O2 to be at risk of that - even when double-dropping/transferring to a secondary (if it was an issue, the breweries that have been double-dropping for over a century would horribly oxidised beer - and they don't). Even with dried yeast where the yeast has been prepared to not "require" aeration/oxygenation of the wort, that doesn't mean that the yeast won't benefit from additional oxygen present. It doesn't 'require' it because you'll get a perfectly good fermentation without aerating the wort. But if you do aerate the wort, the yeast will still consume the oxygen and you'll end up with even healthier yeast (that's why fermentis etc still recommend aerating high SG worts when using dried yeast)

There are tables to enable you to calculate how much O2 to add as you transfer wort to the fermenter but without knowing the exact level of DO that you're starting off with you cannot know within the required precision, how much DO you're going to end up with.

Agree, but in practise for the homebrewer, you're unlikely to introduce "too much" O2 and a rough ballpark of "enough" is "good enough".

 

[hoppyscotty]

All good stuff but if you consider cask conditioning as a form of double dropping though the beer is relatively safe whilst in the cask, I presume due to secondary fermentation that takes place, as soon as the cask is tapped and beer starts to be drawn and air introduced into the headspace then the beer becomes oxidised and spoils very quickly, within a few days, presumably due to the exposure of the beer to air...so beer can be spoiled by simple exposure to air rather than having pure O2 injected into it. Maybe to successfully double drop into another vessel it is essential to have some secondary fermentation to occur in the vessel to purge or consume the air/o2 in the headspace.

 

[MashBag]

Leave it alone and just chuck a towel over it, if there is a real, physical gap.

I do 1000s of liters under a sheet without an airlock. Don't believe the bolleau.

 

[Agentgonzo]

All good stuff but if you consider cask conditioning as a form of double dropping though the beer is relatively safe whilst in the cask, I presume due to secondary fermentation that takes place, as soon as the cask is tapped and beer starts to be drawn and air introduced into the headspace then the beer becomes oxidised and spoils very quickly, within a few days, presumably due to the exposure of the beer to air...so beer can be spoiled by simple exposure to air rather than having pure O2 injected into it. Maybe to successfully double drop into another vessel it is essential to have some secondary fermentation to occur in the vessel to purge or consume the air/o2 in the headspace.

Yes!

When double dropping or casking, the beer will be exposed to air (21% oxygen) and some oxygen will dissolve in it.
But given that the yeast is still active, the yeast will consume the oxygen quickly and prevent the beer from spoiling. This is why beer can be good in casks/bottles for months (or years). Even if you package it without purging the casks/bottles, the yeast (fed by priming sugar or residual sugars at the end of fermentation) will consume the oxygen in the beer/headspace.

But once you tap the cask and let air in, the beer will spoil in a few days.

 

[Agentgonzo]

Leave it alone and just chuck a towel over it, if there is a real, physical gap.

I do 1000s of liters under a sheet without an airlock. Don't believe the bolleau.

Yes, we went down a rabbit hole. Transferring to another vessel will be fine. Open fermenting, or even "very slightly open fermenting" if you're unhappy with the lid will be fine! The active fermentation/CO2 head protects your beer in both cases.

 

[Twostage]

Leave it alone and just chuck a towel over it, if there is a real, physical gap.

I do 1000s of liters under a sheet without an airlock. Don't believe the bolleau.

Yep and I'm sure I've seen piccies on here of open vessels being used.

 

[MashBag]

I agree I am sure I have too, but for the record (and to cover my ***) It wasn't me