Wondering why the label on your favourite wine says "contains sulphites". Curios as to what that means and also what it means for your body...have a read through all the facts about sulphites in wine...
What are sulfites?
Sulfur Dioxide or SO2, is naturally found in wines as a byproduct of fermentation. Most wines you find on the shelf will also have an extra amount added to help preserve the wine against oxidation as well as protect the contents of the bottle from yeasts and microbes that would be undesirable to the finished product.
As a rule of thumb, sulfites are in highest concentration in sweet, white wines and lowest in dry, red wines. White wines are more susceptible to oxidation, and tannins from the skins of red wines act as a natural preservative, hence why we normally see sulfites added in higher quantities in white wines.
Are they harmful?
The simple answer is, no. To most people these do not have much of an effect and are naturally occurring elements in all wines (between 6 to 40 parts per million. The biggest health risk involving sulfites is an allergic reaction.
Some people who suffer from conditions such as asthma seem to have a reaction to wines heavy in sulfites, and there is a common misconception that sulfites have been known to be a factor in the always annoying next day hangover, but this is actually not scientifically factual, and probably relates to an allergic reaction in people who do notice a difference.
If you want to read more about this check out this article on sulfites and hangovers: https://bevologyinc.com/blog/2016/05/26/the-truth-about-red-wine-hangovers-hint-its-not-about-sulfites/
Sulfites are actually used in all types of food production, from frozen foods such as meats and fruits to juices and canned goods. Even our bodies naturally produce them.
Many of the foods you eat contain much more than the things you buy at the grocery store:
Most natural wines contain much less than their normal counterparts, and in many natural wines you will notice that is says" added at bottling only" or "minimal sulphites"
The simple fact is, that hangover is usually caused by the higher alcohol content of the wine you are drinking and not the sulfites (except in circumstances where there is an allergic reaction).
There are standards in Australia which specify labelling instructions and the maximum amount of Sulfites that can be added. To read more about those standards see here: https://www.wineaustralia.com/news/articles/know-your-sulphite-limits
Sulphur-Free Wines
For those of you who do fall in the category of asthmatic or suffering from an allergy, there is hope. There are many wines on the market without any added sulpher, sometimes labelled as "preservative free" or "sulphur free". These wines still contain the natural occurring amount of sulfites, but no extra has been added to the wine artificially.
Your best bet is to read the label or do some research before you buy, and to be mindful of how different wines affect your body and you might discover less sulpher in your wine works for you.