Carboy Headspace or Ullage

Once wine hits the carboy for some aging one has to watch how much headspace or Ullage there us. In case you were wondering what Ullage is, it's the air space between the wine and the airlock. Too much Ullage and your wine can oxidize.

The problem we winemakers encounter is having the right sized carboy to reduce the Ullage. One way to do this is to have enough similar wine on hand to top up your carboy. But sometimes the size of carboy doesn't match the amount of wine. What do you do then?

I have solved this problem by buying 3 and 4 liter used wine bottles. The openings to these bottles are large enough to accept a bung and airlock.

Check out the pics below to see what bottles I use to reduce carboy headspace or Ullage.