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Coloured Wine

How red is it anyway?

How red is it anyway?

The colour of a wine can tell you much about it, but sometimes all is not what it seems.

Blending wines
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.

Wine colours
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.

Conclusion
There are two ways of looking at the manipulation of wine:-

  1. 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.
  2. 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.

Sulphur Dioxide – the Magic Molecule

Sulphur Dioxide molecule

Sulphur Dioxide molecule

Sulphite additions to food and wine have become a big issue. However, the sulphites, and the sulphur dioxide that they produce have real benefits.

Why is the term sulphite used?
Sulphur dioxide is sometimes injected as a gas, but solid sulphite granules are usually added instead. The acid in wine rapidly splits this up to produce sulphur dioxide which actually does the work.

Sulphur dioxide occurs naturally in wine
This may seem unlikely, but fermentation of grapes produces sulphur dioxide without any help from humans. The amount depends on the the yeasts that are used, but it is a ‘natural’ product.

Why are sulphites added to wine?
There are two main benefits:-

  • Antioxidantif wine is exposed to air, the alcohol is quickly oxidised to acetic acid (vinegar). So, nature’s natural tendency needs to be moderated, if we are to drink the wine before it goes off. Sulphur dioxide attacks the chemicals which would otherwise produce vinegar. This is less of an issue for red wines which have their own antioxidants.
  • Antimicrobial – wine contains yeasts and bacteria. The magic molecule prevents these from multiplying and spoiling the wine.

Which wines have the most sulphur dioxide?
SO2 binds with many compounds in wine, including sugar. Only the unbound sulphur dioxide is able to fend off oxygen and microbes. So, sweet wines need plenty to protect them.

The importance of quality grapes
Rotten grapes make rotten wine, and need more sulphur dioxide to keep the bugs under control. Grapes with plenty of acidity also need fewer additions.

What are the adverse effects?

  • Sensoryan excess of sulphur dioxide produces a smell of burnt matches, but an awful lot needs to be added to have this effect. This fault is rare.
  • Healthis a difficult issue because there is little proof of adverse effects. It may induce asthmatic attacks in some people. It is worth noting that normal food metabolism in the body generates much more sulphites than you would absorb from wine consumption.

Conclusion
In my opinion, the addition of sulphites at the right time and in the right quantity is beneficial, if not essential, for almost all wine.