Sorry for such a late and short post; I was without internet yesterday so it was hard to get the research done for this post. Just a quick intro into Sulphur Dioxide as a preservative and trying to demystify it. Preservatives are used to preserve the wines for transportation as well as shelf life, the preservatives do so by reducing spoilage of the wine through oxidisation and wild yeast continuing fermentation. The most commonly used additional preservative in Australian wine is Sulphur Dioxide/Preservative 220, however there is a few others which are also used less commonly.
Wine is alreay preserved by the acid, alcohol and tannins present in the wine. White wine lacks tannins and therefore looses out on it’s preserving features, the upside to this is that white wine often needs to be drunk in the short-term for the freshness of wine is a key part of a good white wine. While some white wines can be cellared for an extended period of time these wines are often higher in fruit flavour and often oaked. Preservation is also dependant upon many features of the wine from for example the grapes, alcohol, tannin and acid content, as well as the device in which wine is stored and it’s permeability.
Some people react badly to the sulphides or preservatives used in winemaking. There are products on the market which will release the sulphides from the wine such as SO2GO and pure wine, these are basically diluted hydrogen-peroxide aka bleach. I personally am not a fan of these additives as have studied chemistry in the past along with having bleached my hair the thought of adding hydrogen-peroxide even in a diluted form to my wine seems not only a sin but also not the smartest thing to do.
Sulphides however tend to me more present in white wine than red wine so when people say they are allergic to the sulphides in red wine they are more likely reacting to phenolics. I will put up a post in the future on phenolics as red wine allergies seem to be a common problem for many people I know and even I have from time to time felt a little rotten a while after a glass of red wine.
Until next time!