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.