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mercredi, 13 février 2013






Sulphur dioxide has been used in wine since the ‘heart’ of the world moved from Geneva to Amsterdam. The Dutch fleet could transport six times more goods than all the other fleets put together. They generalised the use of the ‘Dutch match’ known to-day as ‘méchage’ whereby a match containing sulphur dioxide is burned into the barrel before adding the wine.


It is not possible to make wine without sulphur dioxide as a small percentage (10-15 mg/l) is formed naturally during fermentation. It is, however, possible to make wine with no added sulphur dioxide,  but the risks of making bad wine are high and this is why even the ‘naturalist’ movement recommends its addition but at very low concentrations.


Sulphur dioxide has important properties in wine making.

  • It is an antiseptic which eliminates the unwanted yeasts during fermentation.
  • It has anti-microbial properties that help preserve the wine.
  • It acts as an anti-oxidant dissolving the oxygen which avoids oxidation of polyphenols.
  • It acts as an inhibitor against oxidases enzymes and can even destroy them, hence protecting the majority from oxidation before fermentation.
  • It acts as a solvent allowing the anthocyanes to pass through the grape skin.
  • Finally, it improves the purity of the taste of the wine removing unpleasant odours such as acetaldeydes (ethanol), ketones and pyruvic acid and acts a clarifying agent as it mops up colloidal particles in suspension.


So what are the main risks if there is insufficient sulphur dioxide in the wine?

The oxidation is the greatest problem for white wines. The wine very often has overwhelming aromas of cider and pears and the colour is often very yellow. The reds can re-ferment in bottle. They can smell of sweat, leather, used bandage or even barnyard and farmyard. These odours are attributed to a by-product (4-éthylphénol or 4-EP) of the decomposition of unwanted yeast produced during fermentation called Brettanomyces. Some people, even experienced tasters, actually like these deviations.   It is difficult to understand why, unless as Jancis Robinson suggested in one of her articles, some people are not able to detect  these faults in the wines.   Usually, the better and the more experienced the taster,  the greater he is put off by these deviations. Even when they do not show obvious faults, they have often  lost their sense of place and/or grape variety. 




The greatest problem is that there is no substitute for sulphur dioxide as yet, despite the large amount of research taking place in this field.  I think today most people would agree that the best wines are those called minimal intervention wines, a self-explanatory term.  The key is to grow the best possible grapes and the winemaker will coax them into transforming themselves into good wine, at least that is the theory.  They are usually wines that contain the least sulphur while retaining their full varietal characteristics and their sense of place. Herewith a list (non exhaustive) to make a minimal intervention wine and hence probably make wine within the limit suggested by the naturalists without their usual faults or shortcomings.


  • Use  Massal selection in preference
  • Try to work with auto-controlled old vines.
  • Practise organic, biodynamic or sustained farming.
  • Reduce yields to a maximum of 5 T per hectare.
  • Hand pick grapes in small crates.
  • Pick at optimal maturity avoiding over-maturity, which will produce wines with low pH that will require more SO2 even if the resulting wine does not fit the tasting criteria of some critics.
  • Avoid delay between picking and placing the grapes in the tanks or barrels (this will avoid oxidation and bad start of fermentation)
  • Practice selective sorting of the grapes
  • Maintain good hygienic conditions in the winery
  • Use indigenous yeasts
  • Avoid all adjustments of the musts
  • Use large containers rather than small ones (foudres, demi-muits)
  • Clean used barrels with steam rather than sulphured solutions
  • Avoid racking
  • Used maturation of the wine on fine lees which need oxygen.
  • Increase the delay between alcoholic fermentation and malolactic fermentation
  • Avoid fermentation and maturation at high temperature
  • Bottle the wine without fining or filtration
  • Avoid transporting wine in adverse climatic conditions especially extreme heat
  • Keep your wine at optimal temperatures (13-18o C) or buy from air-conditioned shops



Easy?  Not so sure....... and totally risk free for the consummer?  probably not. 



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