This rather unattractive word belongs to the world in general – not just to wine. The Free Dictionary:
1. The amount of liquid within a container that is lost, as by leakage, during shipment or storage.
2. The amount by which a container, such as a bottle, cask, or tank, falls short of being full.
So, the ullage is the space between the cork and the wine in the bottle. It can also describe the space between the wine in a barrel and the stopper, which is called a bung.
Why do you care? When you see a low fill at the wine shop, it doesn’t mean you just get less wine. It means that the wine could be somewhat oxidized or even spoiled. Oxidation shows up as lost fruit (dullness), brownish color. Wine that has spoiled, outright, is brown and can have many sensory manifestations including a sharp vinegar character or insalubrious fingernail polish remover-like aroma. Continue reading