Sugar plays a vital role in the wine in your glass, even if you can’t taste it directly.
What is sugar?
Sugar is the name given to a wide range of carbohydrates, but only the simpler ones are sweet.
Glucose – one of the main products of photosynthesis in a plant, making up about 50% of sugars in ripe grapes. It is one of the three simplest types of sugar, known as monosaccharides. This is absorbed straight into the bloodstream during digestion.
Fructose – another monosaccharide, making up the other 50% of sugars in ripe grapes. It too is absorbed straight into the bloodstream during digestion.
Sucrose – the type of sugar you put in your tea, is typically produced from sugar cane or sugar beet, and very little is found in ripe wine grapes. Sucrose is in fact a combination of glucose and fructose.
Production of sugar in wine grapes
There is very little sugar in a grape until véraison, when the grape starts to change colour and ripen. Acidity decreases, and sugar contents rise, see the graph in a previous post. The trick is to get the correct balance between the two. Sugar concentrations in ripe grapes can easily achieve 20%.
Adding sugar manually
Before fermentation – sugar in grapes is converted to alcohol during fermentation, but if the grapes aren’t ripe enough, sugar may be added to artificially increase the alcohol content. A process known as chaptalisation. If this is done carelessly, there isn’t enough fruit in the wine to balance the relatively high alcohol. This practice is banned in many wine regions.
Adding two lots of sugar – Champagne manufacture involves adding sugar and yeast to produce bubbles in the bottle, and then sugar at the end to take the edge off the acidity.
Fermentation Yeasts turn the simpler sugars into alcohol plus carbon dioxide, but many other reactions also happen, and some of the complex sugars remain.
Effect of residual sugar in wine
Tasting threshold – for most people this is around 1% sugar content, but those who are particularly sensitive can detect 0.2%. A dry wine which is fully fermented out will have a sugar content of < 1.5 gm/litre, which is not detectable.
Balancing other tastes – sweetness balances acid and bitter tastes, making them less harsh.
Provides food for microbes – residual sugar in wine encourages bacterial growth unless it is properly protected. Sulphur dioxide is important here, see previous post.
In most wines, sugar just has a fleeting presence for a short while before the grapes are picked. It is created by photosynthesis, and consumed by fermentation.
Matching wine and food is not an exact science, and everyone’s taste is different. It is a value judgement. But there are some basic guidelines which help to avoid unpleasant clashes.
artichokes – a challenge to match with wine
The more acidic a wine, the easier it is to match with foods. Think of how a dash of lemon juice enhances some dishes.
Acidic wines deal very well with salty foods such as oysters, or oily fish like mackerel.
The wine should be more acidic than the food. In fact food can temper a wine which would otherwise be too acidic for most.
Alcohol Alcohol in wine affects the texture in the mouth, and if it is too high causes a bitterness and burning at the back of the throat.
Match the weight of the wine with that of the dish. Most foods are fairly light-weight, so it is easier to match lower alcohol, more elegant wines.
Avoid drinking high alcohol wines with chilli or very salty dishes – it just reinforces the burning.
Tannins come mainly from the skin and pips in grapes, so are most often found in red wines. They react with the saliva in your mouth to cause a puckering sensation. Tannin levels decrease as a wine ages, so young wines are more tannic than older ones.
Tannic wines clash badly with many fish dishes, leaving a metallic taste in the mouth.
Tannic wines go very well with fat and protein – grilled steak for example.
Both red and white wines can be oaked, but it is much more common in reds. Oak treatment is expensive, so it is done with better wines. The resulting wine has more body and tannin than lighter-styled wines.
Avoid delicate dishes, as the wine will overwhelm it.
Pick dishes with rich sauces, or where the food has been grilled rather than poached.
Are those with residual sugar. Note that they should also have a balancing acidity, or else they are just cloying and will hardly match any food at all.
The sweet wine should be sweeter than the pudding you are eating.
Semi-sweet wines go well with spicy hot food.
There is no point drinking a wine which you don’t like, just because someone on TV has declared it a perfect match with the food you are eating. In the end, you should drink what you enjoy, but perhaps use the above guidelines to avoid the worst clashes. If a wine really does clash, you can always finish it off after you’ve finished the food.
Blue cheeses provide the biggest challenge when matching with wine. They can be sweet, salty and spicy. These attributes clash with the tannins in red wines, producing a metallic taste. The solution is sweet wine.
Methods for making sweet wines Quality sweet wines are made by dehydrating grapes, which concentrates the sugar. If this is high enough, then some remains after fermentation. Examples of how these are made:-
A fungus called botrytis cinerea, also known as ‘noble rot’, can infect individual grapes under the right conditions. The infected grapes look revolting, but taste delicious.
‘Ice wine’ where grapes are left on the vine until the weather gets cold enough to freeze them. If they are pressed in this state, the juice is very concentrated.
Grapes are allowed to dry on the vine, or after picking, to become raisin-like.
Examples of these types of wine are:-
Sauternes/Barsac from the Bordeaux region. Also look for Loupiac and Monbazillac, less expensive and from the same grape varieties and region.
Sweet Chenin Blanc wines from the Loire – Coteaux de Layon, and Quarts de Chaume. Vouvray is made in many styles, and the sweet versions are labelled Moelleux or Liquoreux.
Sweet Alsace wines, particularly Selection de Grains Noble.
Tokaji from Hungary. The more Puttonyos declared on the label, the sweeter the wine.
Sweet Muscats, made in many countries.
Adding alcohol to stop the fermentation:-
Grape spirit can be added to partially fermented grape juice. This stops the fermentation and retains much of the grape sugar. This method is used to produce sweet red wines. Examples are:-
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.