Wine Preservative: Sulphur Dioxide

Tuesday, August 28th, 2007 at 12:00 am

wine glassThe use of preservatives in wine making is a common practice. Treating the wine with preservatives after it has ferment stabilizes the wine and protect it from any microbial contaminations that would cause spoilage. Most common causes of wine spoilage are bacteria, molds and yeast which are naturally occurring and are always present in grapes. These are also present in winemaking equipment especially those not cleaned properly.

Most often, the effects of microbial spoilage include unpleasant smell and taste of the wine. Winemakers, therefore, have find it vital to add preservatives in their wine. One of the most common preservative used is sulfur dioxide.

Sulfur dioxide have antioxidant properties, stabilizes the wine, function as a solvent and has some effects on the overall taste of the wine.

As an antioxidant, sulfur dioxide prevents the oxidation of coloring substances, tannins, aromas, alcohol and iron present in the wine. Allowing these components to oxidize quickly would affect the taste of the wine. The danger of oxidation is always present from harvesting to every step of the wine making process. As long as the grapes, the juice, and the wine itself comes in contact with oxygen, the risk of oxidation is there. With sulfur dioxide as preservative, winemakers can more or less ensure the consistency of the wine’s taste and maintain its quality.

Sulfur dioxide also slows down the fermentation process. Because yeasts can produce unwanted substances during the fermentation process, sulfur dioxide helps remove these excess yeasts which if left alone can greatly decrease the quality of the wine.

As a solvent, on the other hand, sulfur dioxide helps winemakers extract the coloring substances in the skin of the grapes. Sulfur dioxide is not often used with white grapes since it can draw out too much of the color in the skin resulting to a deep yellow color of the extract.

The preservative was also found to have a good effect on the taste and smell of the wine. Adding sulfur dioxide would help eliminate the possibility that the wine develop that rotting and moldy taste.

With these uses, the importance of sulfur dioxide in winemakeing cannot be stressed well enough. However, due to the dangerous nature of sulfur dioxide, using too much of it in the wine and during the whole wine process have adverse effects on consumers. Moreover, the amount of preservatives is usually regulated by law, such as in the US, Australia, New Zealand, and the European Union.

And because of the dangers from using sulfur dioxide, there are a number of groups trying to advocate the use of alternative methods to help preserve wine. Among the things that winemakers could do are avoiding damaging the grapes during harvesting, cleaning the grapes crusher and other equipment for that matter, maintaining a healthy fermentation process, and the use of a filtration system to screen out substances that could do harm on the the wine.