adding o2 to cider

[fletcher]

hey guys,

just wanted to know, as I'm brewing a simple cider today, if like unfermented wort, the unfermented cider needs to be splashed around also? my guesses tell me no, as I'm not boiling anything (using store bought apple and pear juices, small amount of tea and lemon juice). this is just being added to the fermenter before the yeast. just wanted to confirm if the yeasties needed more o2 or if this would perhaps cause off-flavours.

am I on the right track? yeast is s-04 and hydrated.

 

[gap]

Oxygen is a big no no for cider.

 

[fletcher]

Oxygen is a big no no for cider.

thanks mate.

is there a simple explanation as to why? no worries if not.

 

[Airgead]

Oxygen is a big no no for cider.

Whoa there....

Its more complicated than that.

Oxygen once the yeast kicks into anaerobic phase is a big no no just like in beer. It promotes acetobacter, off flavours and is otherwise generally undersirable.

Oxygen before you add yeast will also oxidise the juice and make it go brown and yuck. Although some controlled oxidisation of the juice can add some colour and flavours to the finished cider.

But oxygen while the yeast is actively reproducing is essential.

Having said that, I find that the juicing process incorporates enough oxygen that I don't need to add extra. But then again i usually pitch yeast within a few hours of pressing. If you leave your juice to stand for a while between pressing and adding the yeast, or if you use shop bought juice, some aeration may well help the yeast get a good start. The active yeast will quickly scavenge the o2 and protect the juice.

 

[fletcher]

Whoa there....

Its more complicated than that.

Oxygen once the yeast kicks into anaerobic phase is a big no no just like in beer. It promotes acetobacter, off flavours and is otherwise generally undersirable.

Oxygen before you add yeast will also oxidise the juice and make it go brown and yuck. Although some controlled oxidisation of the juice can add some colour and flavours to the finished cider.

But oxygen while the yeast is actively reproducing is essential.

Having said that, I find that the juicing process incorporates enough oxygen that I don't need to add extra. But then again i usually pitch yeast within a few hours of pressing. If you leave your juice to stand for a while between pressing and adding the yeast, or if you use shop bought juice, some aeration may well help the yeast get a good start. The active yeast will quickly scavenge the o2 and protect the juice.

thanks airgead. my s-04 is actually in a stir plate and getting oxygen before i pitch it. i don't often do it for dry yeasts but i had a pinch that i've stepped up just because. i will also add 1/2 tsp yeast nutrient to the tea i boil too. would this be sufficient? i'm happy to give it a little splash if required when everything is all in the fermenter.

 

[Airgead]

Yeast needs oxygen when its growing and dividing. So if you are getting enough yeast reproduction on the stir plate then you won't need so much oxygen in the main cider.

If its shop bought juice it will probably have been treated with antioxidants so it will have close to zero available oxygen in it to support any yeast growth. The yeast will still want to keep dividing once you pitch it and a lack of oxygen will inhibit this. This means a ferment with much lower numbers of yeast cells so a long, slow fermentation. It may even stall early depending on a bunch of factors (yeast health, nutrient levels etc). This may be desirable if you want a sweeter end product but its hard to do consistently.

Some sweet ciders are made by deliberately stripping the juice of nutrients and o2 in a process called keeving.

If you are using freshly pressed juice, there will be plenty of available oxygen unless you used an antioxidant.

The short answer though - if you aren't sure there is enough o2 to support good yeast growth then a little shake wont' hurt.

Cheers
Dave

 

[fletcher]

Yeast needs oxygen when its growing and dividing. So if you are getting enough yeast reproduction on the stir plate then you won't need so much oxygen in the main cider.

If its shop bought juice it will probably have been treated with antioxidants so it will have close to zero available oxygen in it to support any yeast growth. The yeast will still want to keep dividing once you pitch it and a lack of oxygen will inhibit this. This means a ferment with much lower numbers of yeast cells so a long, slow fermentation. It may even stall early depending on a bunch of factors (yeast health, nutrient levels etc). This may be desirable if you want a sweeter end product but its hard to do consistently.

Some sweet ciders are made by deliberately stripping the juice of nutrients and o2 in a process called keeving.

If you are using freshly pressed juice, there will be plenty of available oxygen unless you used an antioxidant.

The short answer though - if you aren't sure there is enough o2 to support good yeast growth then a little shake wont' hurt.

Cheers
Dave

thanks for the info. i'll give her a little shake and pitch what I have. it's not a full batch (only 10ish litres) so a stepped 5gms of s04 I think would be a sufficient amount of yeast but yes, I do understand they need to multiply once pitched. would be happy if it stalled a bit but am not counting on it. i'll report back once done

 

[Greg.L]

Keeving doesn't have anything to do with oxygen as such, but the general rule with cider is to keep oxygen away. Oxygenating the juice before fermenting won't hurt but there's no real reason to do that. The oxygenation from juicing and pressing is beneficial in some ways, and helps with colour, but once fermentation starts you need to keep air out. it pays to be a bit paranoid about oxygen if you make cider, the less oxygen the better the cider.

 

[Donske]

Keeving doesn't have anything to do with oxygen as such, but the general rule with cider is to keep oxygen away. Oxygenating the juice before fermenting won't hurt but there's no real reason to do that. The oxygenation from juicing and pressing is beneficial in some ways, and helps with colour, but once fermentation starts you need to keep air out. it pays to be a bit paranoid about oxygen if you make cider, the less oxygen the better the cider.

You've posted about oxygen in cider a few times, even going as far as saying plastic fermenters shouldn't be used, which makes sense to an extent, and there being enough o2 available to the yeast after pressing also makes sense to me, the thing I'm curious about is if you are using store bought juice to make cider, I'm guessing that Airgead is right about it containing antioxidants to avoid staling in which case we'd need to reintroduce a certain amount of oxygen to allow for yeast growth.

The thing is, how much, would splashing into fermenter from height be enough, a bit of a shake of the fermenter, o2 through an airstone?

 

[Greg.L]

It is important to rehydrate yeast for cider, but my opinion is that enough o2 dissolves that you don't need to make any special effort to dissolve more. It doesn't hurt to agitate or splash so if you feel more o2 is needed that is fine.

Plastic fermenters are fine for the short term but no good for more than a few months if they are well sealed, the same goes for PET bottles.

I don't use store bought juice, anti-oxidants don't stop oxygen dissolving but "mop up" the undesirable products of oxidation.

 

[Donske]

It is important to rehydrate yeast for cider, but my opinion is that enough o2 dissolves that you don't need to make any special effort to dissolve more. It doesn't hurt to agitate or splash so if you feel more o2 is needed that is fine.

Plastic fermenters are fine for the short term but no good for more than a few months if they are well sealed, the same goes for PET bottles.

I don't use store bought juice, anti-oxidants don't stop oxygen dissolving but "mop up" the undesirable products of oxidation.

Would that mean that any staling effects from oxidation would be mopped up by the antioxidants in store bought juice or are the compounds that cause staling post fermentation different to those pre fermentation?

Staling isn't too much of an issue personally as cider kegs get destroyed once I put them on tap but on the off chance I bottled some for give aways it would be nice to know.

 

[Greg.L]

The main anti-oxidants in juice are SO2 and ascorbic acid. After fermentation the so2 will be bound up and inactivated. I am not sure what you mean by "staling" do you mean the cider going stale? The best way to keep cider fresh is to keep out air, but if you are concerned, 50ppm so2 post-fermentation will also help. Keeping cider on the lees also helps to stop oxidation.

 

[Donske]

The main anti-oxidants in juice are SO2 and ascorbic acid. After fermentation the so2 will be bound up and inactivated. I am not sure what you mean by "staling" do you mean the cider going stale? The best way to keep cider fresh is to keep out air, but if you are concerned, 50ppm so2 post-fermentation will also help. Keeping cider on the lees also helps to stop oxidation.

By staling I basically meant any adverse effects of oxidation, maybe not the best use of terminology.

Cheers for the info, seems I've got more reading to do.

 

[Airgead]

I wholeheartedly concur with greg on the plastic fermenters - fine for an active ferment but don't age in them. For that you want something impermeable.

I also never use shop bought juice so have little experience with it. Crushing and pressing adds more than enough for a good fermentation if using fresh.

 

[Mutaneer]

I wholeheartedly concur with greg on the plastic fermenters - fine for an active ferment but don't age in them. For that you want something impermeable.

What's the consensus on aging in oak?

 

[Ferg]

I agree that O2 should be kept out as much as possible from your cider post active fermentation. I have found that the ciders that I have sealed off in kegs, glass bottles or whatever are much better. When you get some oxygen contact you tend to get a very slight wine/vinegar smell & taste.
This year (for the small quantities I will be making due to f#*cking birds) I will be making as much effort as possible to exclude O2. Interestingly these guys (http://custardco.com.au/products/) do their scrumpy in open vats. I have tasted it and it is pretty good but completely different to anything else out there.
I have experimented with leaving the pomice overnight to promote some colour in the cider - it worked really well actually and makes the apple juice more viscous. I think you tend to get a better yield from the juice too.

As for ageing on oak, I did that last year with one of the 100l wine barrels that came from SA. I'm not totally sold to be honest, it is a lot of hassle and the cider developed a film yeast. I will also probably have to turf out the barrel because I didn't clean it immediately afterwards, in fact there is probably still about 10l of cider still in there and I would imagine it has turned to vinegar. In short, unless you are prepared to properly maintain the barrel don't bother - im too scared to put anything back in there this year as it would probably be my whole years worth buggered.

 

[Mutaneer]

hmmm,
I've only got a 5L barrel, to which I'm "seasoning" it with whiskey for 6 months or so.
I was hoping the residual (high %) alcohol in the timber itself would help to ward off any nasties,
And have it filled completely to the brim so there is no air in there at all.

 

[Ferg]

To be honest I haven't read many good things about cider aged in whiskey barrels although Willie Smiths did one in old Lark barrels. Rum & wine seem to be preferable but at 5 litres you are not losing much by trying it out. There are plenty of recommendations on how to prepare and keep a barrel - give it a google.

 

[Mutaneer]

Yeah, The Willie Smiths/ Lark drop is my inspiration,
Especially as I frequent both the Willie Smiths and Lark cellar doors often.

Shameless plug, a MUST DO for anyone visiting Hobart,
Lark on Friday night for some Folk/ Blues tunes and fine whiskey/ craft beers, etc,
Then a lazy Sunday afternoon at Willie Smiths Apple Shed.!!