Sulfur Dioxide (SO2)

SO2

Is almost indispensable in the winery. It acts as an antioxidant and an antiseptic.

Although some SO2 is produced naturally in fermentation, most winemakers agree that keeping additions of SO2 as low as possible is

Preferable, not least because if levels become too high the wine can seem harsh and lacking in fruit.

Antioxidant effects

SO2 protects the grape juice and wine from the effects of oxidation. In doing this SO2 loses the ability to have any further protective effect and becomes when is know as BOUND

Antiseptic effects

So2 is toxic to the many strain of yeast and bacteria that can cause unwanted flavor in wines. Fortunately for winemakers the principal yeast involved in the alcoholic fermentation is able to tolerate levels of SO2 that are toxic to these other species.

SO2 can be used to protect

Freshly harvested grapes and levels are adjusted throughout the winemaking process

SO2 can also cause

Allergic reactions even at low levels.

The upper levels of SO2 in wine

Are strictly controlled by law because it can be toxic (although the concentrations found in wine lie far below toxic levels and are lower than those that can be found in dried fruit).