The key to storing unopened wine is about consistency, and there are six main factors to consider. First and potentially the most important is temperature as this can cause a range of issues. Bottles should be stored at room temperature ranging from 10-15 degrees Celsius, obviously a couple of degrees either way isn’t disastrous but it’s a good guide. Above this then the wine can ‘cook’ producing stale, unwanted flavours. If a corked wine is kept in the fridge, then it can cause shrinkage of the cork allowing air to enter into the bottle and oxidise the wine.
Another factor for bottles sealed with a cork is the angle it is stored. In order for the bottle to remain sealed the wine inside must stay in contact with the cork otherwise it will dry out, if this occurs then oxidation can occur, therefore horizontal positioning is vital. For bottles secured with a screw cap then this isn’t a concern and any angle will do.
Vibrations, this is only the case if there is sediment in wine, if so then keeping the wine still is important as this can affect the quality of the final pour.
Humidity, if a wine is sealed with a cork then it's crucial the room is not too dry and there is a slight moisture in the air otherwise the cork can dry out and oxidise. However, if the humidity levels are too high then this can cause damage to the label, although this is only an aesthetic issue and occurs slowly.
Not keeping the bottles away from direct sunlight. This will cause changes in the wine and ruin the bottles. Ultra violet light commonly known as UV, causes colour damage and reduces the wines stability meaning the aromas and flavours change. Ever wondered why wine bottles are often green? the coloured glass limits the impact of the light strike meaning less damage occurs. Discussed more in Faults and Flaws.
The last factor in wine storage is keeping the bottle out of contact with strong smelling odours as these can impart into the wine and affect the overall taste, reducing flavours that are critical to enjoying the product.
Once opened the key is to reducing the wines' contact with oxygen to a minimum. There are two main methods of wine preservation once the bottle has been opened. The first is known as a ‘blanket system’ here the oxygen is removed from the bottle by an inert gas, this technique is affective but far more commonly used in professional situations e.g. restaurants or wine stores.
The second and more affordable option is the vacuum system using a pump. This gadget removes the oxygen from the opened bottle by sucking out the air, creating as the name suggests a vacuum. A pump and two seals can be purchased for under £10, they can preserve the wine for an extra 3-5 days.
Another key factor when storing open wine is reducing the surface area to volume ratio. This means reducing the amount of wine in contact with oxygen. It can easily be achieved by keeping the wine in a vertical position so only a small circular section of liquid is accessible to contact.
Finally sparkling wines. There are many theories and suggestions about the storage of open sparkling wine for example placing a teaspoon in the neck of the bottle to retain the bubbles. Most of these theories and the given example have no scientific backing. The best way to retain freshness and fizz is to again seal the bottle using a vacuum. Using the original cork to reseal the wine is unlikely to work due to the pressure in the bottle, that will cause the cork to pop out. Keeping the wine cold is also vital. The lower temperature will keep the carbon dioxide dissolved in the wine. Combining both these techniques will extend the wines' life but only for an extra couple of days as the quality will rapidly decrease.
Oxidation- see Faults and Flaws
Vacuum- ‘creating a space void of matter.’ Removing the air, especially oxygen within the bottle by suction.