Category Archives: UV light

Bottle variation

Bottles of the same wine may taste very different, and variations increase as a wine gets older. In fact one bottle of a mature wine may be wonderful, and the next over-the-hill. Why?

different bottle sizes

different bottle sizes

The blend
Virtually all wine is a blend from different barrels or vats. If the mixing vat is not big enough to take all the wine, then one batch may well differ from the next. So, there may be a difference before the wine is even bottled.

Bottling
A particular wine may be bottled in batches rather than all at the same time. The fill levels, added sulphur dioxide, entrained oxygen, and gas injected above the wine may all vary at each bottling session.

The closure
Historically this was always natural cork. It is a fine closure, but every cork is different and will allow differing amounts of air to diffuse through. This causes bottles to mature at different rates. One big advantage of screwcaps is that each closure is the same.

Transport and storage
This is a major issue, and can completely destroy a wine.

  • Temperature – is covered in more detail by another post. If the temperature gets too high, the wine will be damaged, perhaps fatally. Cases of wine stored at different temperatures will mature at different rates.
  • ‘Lightstrike’ – damage by over-exposure to UV light.

Bottle size
The larger the bottle, the more slowly and gracefully a wine matures. This may just be because the gap between the cork and the wine is the same for a half bottle, a bottle or a magnum. Any air in that gap will be spread more thinly in a magnum than a half bottle, meaning that it will be oxidised more slowly.

Age of the wine
The older a wine, the more time there is for all these influences to take effect, and the higher the chance of one bottle being very different to the next.

Wine storage – what you need to know

Wine rack

A classic wine rack

Wine is alive, and there are two things which will kill or maim it in no time at all, they are direct sunlight, and temperatures above 25°C (77°F). Even if you are going to drink a wine soon after buying it, beware shops and restaurants where these conditions apply.

Light, aromatic wines are most susceptible, and heavy reds the least.

Sunlight has two harmful properties – ultraviolet light (UV) light, and radiation which heats what it shines on. UV light encourages the breakdown of many chemicals, and the oxidation of others. All this is bad news for the wine. Coloured glass provides some protection.

Temperature. High temperatures cause some chemicals to breakdown, and others to react rapidly. New and unpleasant compounds are also produced.

Avoid rapid changes in temperature as this can cause the cork to move within the bottle, and allow air in. This influx of air causes the wine to go off more quickly.

Ideal storage conditions are:-

  • Temperature:- 12°C to 13°C (54°F to 56°F).
  • Humidity:- 60 to 70%. If the cork dries out it will let air into the wine.
  • Horizontal:- the cork should be in contact with the wine, to prevent it from drying out.
  • Keep it in the dark. No sources of UV light or heat.