Monthly Archives: February 2013

Why use Wood in Wine Production?

wine barrels

Wine barrels in a Burgundy cellar

Fermenting and maturing a well-made wine in oak barrels softens the wine, and makes it more complex.

Four things happen when a wine sits in an oak barrel:-

  • Chemicals are leached out of the wood, which provides the distinctive vanilla taste, amongst others.
  • Small amounts of air pass through the barrels, which influences the way the wine matures.
  • Some wine is absorbed into the barrel, and some alcohol evaporates. So the wine in the barrel needs to be topped up.
  • The wine is gently clarified.

Types of oak and their treatment
Several different types of oak are used, and each gives a different taste. The oak is split into strips, known as ‘staves’, and allowed to dry outside. This seasoning removes the harsher tannins in the wood. The barrels can be further treated by burning the inside, a process known as toasting, which also reduces the flavour and tannins which are imparted to the wine. This video by Jordan Winery tells you all you need to know.

New barrels vs old
Old barrels, which have been used before, will impart less taste than new barrels, as most of the chemicals have already been leached out.

Large barrels vs small
Large barrels impart less taste than small ones, because the flavour is diluted over a larger volume. Also, the air that penetrates the barrels is spread more thinly in large barrels, which leads to slower ageing.

Oak chips
Some winemakers put oak chips into their wine while it is maturing, to give it ‘oak character’. This is obviously cheaper than using oak barrels, and is used on cheaper wine, sometimes with unfortunate results.

Where it can go wrong
The use of oak in winemaking is a complicated business, and a great deal of skill is required in dealing with it. Several factors are listed above, but there are more besides. Most importantly, the wine needs to be tasted during its evolution. Not all wines improve with exposure to oak, and it is easily overdone.

Wine does have Calories

sticky buns


Everything in wine, apart from the water, has calories. Wine is made up of many different chemicals, but the main ones are alcohol, sugar, and acid.

Alcohol has far more calories than sugar – 7 kcal/gram vs 4 kcal/gram.

Ripe grapes have acids and sugar, but no alcohol. In the simplest case, fermentation converts all the sugar to alcohol (ethanol). So, a light and fully dry Sauvignon Blanc will have around 500 calories in a 750ml bottle. A moderate-sized glass holds 150ml (5 US fl.oz.), so would provide you with 100 calories – an essential part of a balanced diet.

Riper grapes will have more sugar, which will be converted to more alcohol. So, a Cabernet Sauvignon with 15% alcohol from a hot part of the world, may well have 800 calories in a 750ml bottle.

Champagne has a moderate alcohol level of about 12%. However, almost all Champagne has an added ‘dosage’ of sugar before the cork is inserted. This means that it typically has 600 calories per bottle.

Sweet wines are a little more complicated – it depends on how they are made. These are usually served in small glasses, which lowers your alcohol and calorie consumption:-

  • A German Riesling Spätlese, with a low alcohol of 9% and some sugar, may be 500 calories per bottle.
  • A top Sauternes from a great year can achieve 1200 calories per bottle.
  • Port, which is made by adding alcohol to stop the fermentation, is 1200 calories or more per bottle.

This isn’t stated on most labels, but perhaps it should be.