Probably a daft question

[chub1]

Can i use my beer fermentation bucket to brew 'easy cider' made with pure apple juice and raspberry syrup,of around 7 litres or will the apple juice oxidise due to the large head space in the FV.
Thanks

[oldbloke]

It's more of a risk, certainly, but if you don't slosh it about to disturb the layer of CO2 that forms on top it should be fine.
But, why not pick up a demijohn or two from a boot sale or similar? Or buy a couple of 5l bottles of water from the supermarket?

[vacant]

Sugars ferment to roughly 50% alcohol and 50% CO2 by weight. If you start with 7 ltr (approx 7000 grams) and end up with 500g alcohol then 500g CO2 given off will occupy 280 ltr (ten times the volume of the bucket (pdf)).

CO2 is denser than air so forms a layer over the liquid. Lastly beer can be brewed in open fermenters.

Anyway, that's from someone who has never made cider so there may be overwhelming reasons why a large head space would be a bad idea? I'd wait a bit for an expert to comment.

[TheSumOfAllBeers]

Like vacant said, the CO2 generated during fermentation will completely displace all the O2 in the headspace, even if the headspace is quite large.

However I would caution about over depending on co2 density as an oxidation protection. Co2 is a gas and will mix readily with other gases.

Gas stratification only occurs in very careful circumstances.

[chub1]

Thanks all.
Oldbloke, i really don't want to get more equipment if i can avoid it, my beer gear takes up enough space indoors as it is, along with all my fishing tackle and trains
I might consider doing 20 ltrs instead which will leave only a small amount of head space and chance it

cheers