The truth about sulphites in wine

About sulphites

The role of sulphites in winemaking is to prevent oxidation (the conversion of alcohol to acetaldehyde which removes fruit aromas and flavours) and to prevent microbiological spoilage of the wine by killing undesirable yeasts and bacteria.

Sulphite (SO2) exists in two main forms in wine – free SO2 and bound SO2. The addition of free and bound is referred to as total SO2. Free SO2 refers to molecular SO2 and lightly bound bisulphite and sulphite anions.  Bound SO2 refers to the sulphite anions which are bound strongly to other compounds such as acetaldehyde, colour pigments and tannins in the wine.

Sulphite sensitivity

The presence of sulphites in foods and beverages, even in very small amounts, has been shown to cause allergic reactions, in particular asthmatics. Reactions can include wheezing, flushing, low blood pressure, migraines and skin rashes. It is estimated that around 2% of the population may be sulphite sensitive and this does not include asthmatics who can also be affected.

Preservative free red wines will age normally due to the presence of naturally occurring tannin and acid and alcohol which act to preserve the wine and allow it to age slowly. Preservative free white wine has alcohol and acid but not tannin and so whites made without sulphite are subject to aging more rapidly than white wines made with SO2.

White wines generally contain the highest levels, usually above 100ppm total with a higher percentage as free SO2 often around 25-35ppm. Asthmatic consumers often react most violently to white wines due to the higher level of free SO2. Red wines generally contain lower levels of about 70ppm total and about 15-20ppm free.  Sulphite sensitive consumers react to both red and white wines due to the presence of any total SO2.

Sulphur Dioxide is often added to wine as PMS (Potassium Metabisulphite) or as molecular SO2. Its addition to wine has been allowed for centuries due to the fact that it is a natural by-product produced by most yeast during alcoholic fermentation.

Organic wines and sulphites

A large number of organic wines contain sulphites, unless a wine says it is sulphite or preservative free, then it will normally contain sulphites.  Organic wines which state naturally fermented with indigenous yeast and no sulphite added, will also often have sulphite present due to the wild yeast producing some during fermentation. If it’s organic doesn’t mean sulphite free. In Australia organic wines can contain up to 120ppm SO2 under organic status.

The use of SO2 reducing sprays such as SO2GO is effective at removing free SO2, however it does not remove all the sulphites in wine. In fact after the initial spray, free SO2 will start to reform as some of the bound SO2 releases to reform free SO2.

What makes Em’s Table Organic Shiraz different?

Em’s Table Organic Shiraz contains no sulphites (zero free and zero total SO2) and will age just like any other quality red wine – 6 years or more.

Em’s Table Organic Shiraz is made using a specially selected strain of yeast that does not produce sulphite under normal fermentation conditions. Oxidation is prevented using CO2 (dry ice) to cover the wine during storage and making. The wine is sterile filtered into bottle removing all yeast and bacteria, so that once the wine is in bottle it is safe and will age like a normal red wine for 6-8 years in bottle.

The techniques used to produce this wine were developed in 1990 by Macaw Creek winemaker Rod Hooper as part of a research programme established at Charles Sturt University. The first vintage of a preservative free wine under the Macaw Creek label was in 1992.

Em’s Table Organic and  Preservative Free Shiraz is the next step in Macaw Creeks preservative free winemaking, produced from a fully (NASAA approved) certified organic vineyard in the Clare Valley of South Australia as a full bodied red wine with ripe  fruit characters.

Em’s Table is a great Australian Shiraz which also happens to be preservative free, so that all consumers sensitive to sulphites or those choosing to reduce their intake of chemicals, can enjoy a quality red wine.