Originally Posted by cheezydemon3
I've only made one batch of vino, but during the clarifying secondary, there is air in contact.
Unless you fill a carboy up to the neck, there is the same surface area whether 4 gallons or 5.
Absolutely. That is why winemakers will fill the carboy up to within an inch of the bung, to prevent oxidation. Some use sanitized glass marbles, if the headspace is already minimal and just needs a "boost". If there is 4 gallons, an ideal set up would be a one gallon and three gallon carboy, or a three gallon carboy filled, and then a growler or wine bottle or whatever is available to hold the rest of the wine without any headspace.