Headspace, cider, primary, secondary

[siletzspey]

For 2 seasons, I've put fresh pressed apple juice into 1 and 3 gallon carboys, and had no foam-out issues with just ~1 cup of airy headspace in the primary. While pressing apples with friends yesterday (50+ gallons), they had been told to leave ~1/3 of the bottle as headspace.

Other than leaving headspace to guard against foamy blow out, the only other occasional argument I see for headspace during primary is that the yeasts supposedly need O2 early on. Is this true?

I'm under the impression that CO2 quickly pushes the O2 out, so assuming the yeast needs O2 early on, it would seem leaving lots of headspace would be worthless, and some other approach should be used. True?

For secondary, I've been fine at ~2oz headspace.

--SiletzSpey

 

[Yooper]

You don't really need headspace for cider, if it doesn't foam. Sometimes a few of mine do foam up, especially if I use an ale yeast strain. It's true that in primary, the yeast can benefit from oxygen, but I don't worry about it as it seems like apple juice has plenty of nutrients. If I get some "stuff" on top, I stir it in, and that helps to degas the cider a bit and allow oxygen contact.

Often, winemakers don't even cover their fermenters in primary except for with a clean towel to keep out critters. At this time of year, though, I often get a ton of fruitflies so I will cover and airlock if needed.