The addition of sulphur is an extremely effective method of preservation, stabilisation and sterilisation in winemaking. In this sense, sulphurisation has three essential functions:
Sulphur binds oxygen and thus protects against Oxidationwhich can impair the flavour of the wine.
Sulphur inhibits Enzymeswhich can have a negative influence on the development of wine.
Sulphur removes Microorganisms(yeasts, bacteria, etc.) that can negatively influence the development of wine and spoil it.
Already in the Vineyard sulphur is used as the most effective remedy against fungal diseases such as powdery mildew - also in organic viticulture.
In the Wine cellar sulphur is used in various production steps. For example, the must or mash is already sulphurised to prevent uncontrolled fermentation or oxidation; after fermentation or pressing, theyoung wine is sulphurised to stabilise it; in the course of ageing, it is sulphurised again if necessary; and before bottling, it receives its final sulphurisation to preserve it.
How often and how much sulphur is added depends on a variety of factors - from the grape variety to the quality of the grapes, the production process, cellar hygiene and the desired ageing style. Through its reductive and antiseptic effect and its reaction with other chemical elements, sulphur also influences the smell and taste of the wine.
Sulphur is added in the form of sulphur dioxide, sulphurous acid (sulphur dioxide dissolved in water) or potassium pyrosulphite (the potassium salt of sulphurous acid, abbreviated KPS). The sulphur combines with the water in the wine to form sulphurous acid, and its salts are called sulphites. This is why virtually all wine bears the legally prescribed label "Contains sulphites". Natural wines are usually bottled with minimal sulphurisation or unsulphurised. Their shelf life is often achieved through oxidative ageing.
Sulphites are harmless to health in the quantities permitted by wine law. According to current scientific findings, they are not responsible for possible headaches after (excessive) wine consumption, but biogenic amines (e.g. histamine), which are also contained in wine.