Trim the angels’ share
If you age your whisky, beer or wine in wooden barrels, you generally have to be prepared to lose some of it along the way. Non-air-tight containers and evaporation mean that over time barrels (and wine bottles with natural corks) end up with a headspace of air between the liquid and the top of the container. The missing liquid is known as the ‘angels’ share’ and the remaining space as the ullage (from the French ouillage).
There is a balance to be found here. Winemakers know that they need to share a little with the angels – some oxygen is needed to break down tannins and so on – but they don’t want to overshare: too much and the wine will be ruined.
This is why wine kept in barrels is regularly topped up, but also why wine dealers look carefully at the ullage levels in old bottles. Wines kept in the wrong conditions will evaporate faster than those kept at the correct temperature and humidity. Old wines with higher than usual ullage are thus deemed to be of less value (thanks to the higher risk of oxidation) than those with normal ullage.
You’ll be wondering what this has to do with your non-wine investments.
• Read the full editor’s letter here: Trim the angels’ share.