The colour of a wine can tell you much about it, but sometimes all is not what it seems.
Decades ago it was quite normal for a Burgundy producer to add a good slug of wine from a warmer part of the world to make up for any deficiency in their product. In theory this shouldn’t happen any more, and better vineyard practices and winemaking skills have improved the wines. There are rumours of this sort of practice still happening in some regions; and in some parts of the world the geographic boundaries are so large that blending is normal practice.
What gives a wine its colour?
The colour comes mainly from the grape skins. A classic example of this is the Pinot Noir grape variety. It normally makes red wine, but the pulp in the centre of the grape is white, so, if you gently press the grapes, and ferment the juice you get a white wine, as in Blanc de Noir Champagnes.
I’ll exclude fortified wines.
White – wine made by pressing grapes, and fermenting the juice without skin contact.
Orange – wine made from white grapes, but where the skin is in contact with the juice during fermentation. This was very unusual, but is becoming more popular.
Rosé – wine made from red grapes, where the grape skins are left in contact with the juice for a short period to impart some colour.
Red – where the grape skins are left in contact with the juice throughout fermentation. The colour can vary from a pale garnet to an inky impenetrable purple.
Which other factors influence the colour?
Acidity. Usually expressed as the pH. The acidity decreases as a wine ages.
Sulphites. These are added as an anti-oxidation and to kill off bacteria, but they also change the colour of a wine.
Ageing. The chemical reactions in a wine cause white wines to become darker in colour as they age, and red wines to become paler. They all tend towards brown in the end.
Oak barrels. Some air reaches the wine whilst it is an oak barrel, and this can affect the colour, as can some chemicals leached from the oak.
Wine additives which influence colour
In addition, or instead of, blending wine from outside the region, some winemakers will add food colouring. The most honest of these are at least grape-derived, an example being ‘Mega Purple’. They are concentrates where a little goes a long way, and some change the taste as well as the colour.
It is also possible to remove colour by using activated charcoal.
There are two ways of looking at the manipulation of wine:-
The wine reflects the area that it comes from, often referred to as terroir, and also the winemaker’s skill. The addition of wine from outside the area, or wine concentrate, masks the individuality of the wine and so detracts from it.
The winemaker aims to produce a consistent product every year, and that additives which achieve that are entirely justified. Cynics might suggest that they simply make up for poor winemaking. It should be said that the blending techniques used in Champagne to achieve a standard non-vintage wine are an honest way to achieve a consistent product.
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.