The term ullage is used to describe the amount of headspace between the bottle closure and the liquid inside a wine bottle. But how important is this and what does it mean for the condition of the wine?
The ullage, or headspace, is one of the key things that you should look for, particularly in more mature vintages. If you buy from auction houses, for example, you should pay close attention to ullage as part of your assessment of the wine’s condition.
It is the best guide you have to the condition of a bottle of wine, especially if you don’t know for certain how it’s been stored. The ullage level can give you a few clues about the wine before you have the opportunity to open the bottle.
OLDER BOTTLES
The fill level of the wine (along with seepage, colour and signs of tampering with the label) should be the first thing you must check when buying older bottles.
I’d usually discuss with my guest if the level looks particularly low, and suggest that it would be best to open and taste the wine before agreeing to consume it.
In a restaurant it’s a risk that’s worth taking, because invariably they will open another bottle if the first is not right.
If the fill level is low, it suggests that air has been seeping into the bottle, which would cause the wine to oxidise.
You should look at it as a marker of how well the wine’s been stored, as lower fill levels (in the bottle neck) and seepage usually point to heat exposure and poor storage.
It is often the age of the wine that will determine whether ullage is of concern. A bottle naturally evaporates very slowly through the permeable cork, so it is only expected that a 40 year old bottle will be less full than a current vintage of the same wine.
In short, the ullage level will give you a few clues about your wine before you have the opportunity to open it.
For instance, a bottle of Bordeaux (shape) with ullage down at the ‘low shoulder’ (where the curvature from the neck becomes the body of the bottle) is risky. I would only purchase it if the wine or label is exceptionally rare or interesting.
‘Top shoulder’ is normal for any wine 10 years or older, while ‘mid-shoulder’ isn’t abnormal for a 20 to 30 year-old wine.
Ullage in Burgundy (Pinot shape) bottles is measured in centimetres, because of the bottle shape. The condition and drinkability from Burgundy bottles is less affected by ullage than its equivalent Bordeaux
An idea is if you are buying an expensive older bottle of wine in a shop (10 years old or more), line up all the available bottles and choose the bottle with the highest fill, just to be safe.
But remember, this is not a foolproof method.
What I have discussed is not a totally reliable measure of condition. Because you do sometimes come across old bottles with a very low fill that have remained in good nick.
Like most aspects of a wine, the clues can only be confirmed once the wine is tasted, but it’s certainly a help by analysing its condition first.
