Everything you need to know about calcium sulphate (E516)

dans le vin

Did you know that calcium sulphate, also known as gypsum, is used to regulate the pH of liqueur wines? Find out more about its role in wine, and its other uses.

Calcium sulphate is a mineral compound that acts as an acidity regulator, used exclusively in liqueur wines, meaning wines created by preventing fermentation of the grape must through the addition of brandy. Its main function is to lower the pH of must destined for these wines, thereby intensifying their freshness and balancing their aromatic profile. This natural mineral, more commonly known as gypsum, has unique properties that make it an asset to other food sectors also.

What is calcium sulphate (or gypsum)?

Calcium sulphate is a natural mineral composed of three essential elements: calcium, sulphur and oxygen. In its natural form, it is known as gypsum. In oenology, it is used to regulate and adjust the acidity of liqueur wines. Although it may seem to make only a modest contribution to the winemaking process, gypsum plays a crucial role in the final balance of flavours and acidity in a liqueur wine.

What is calcium sulphate used for in wine?

The main role of calcium sulphate is to intensify the acidity of a wine by adjusting its pH. It is reserved exclusively for must destined for the production of liqueur wines, where this intensification of acidity is particularly sought-after to guarantee an optimal flavour balance.

By lowering a wine’s pH, calcium sulphate enhances its freshness and helps structure its aromas. Its use is strictly regulated, and it is not permitted in other categories of wine, such as traditional reds, whites or rosés.

More specifically, why is it called a “pH regulator”?

Unlike organic acids such as malic, citric, lactic or tartaric acid, calcium sulphate acts on the acidity of must by interacting with other compounds present in wine, particularly tartaric acid. This chemical interaction leads to a decrease in pH, and thus an increase in perceived acidity.

In oenology, pH plays an essential role, influencing not only the microbiological stability of a wine, but also its organoleptic qualities, such as freshness and balance. Thanks to its effect on pH, gypsum helps improve the perception of acidity in liqueur wines, making them more harmonious and pleasant to drink.

When is calcium sulphate used in wine production?

Calcium sulphate can only be added to must prior to alcoholic fermentation. At this stage, the winemaker determines whether an adjustment in acidity is necessary to obtain the desired profile. This early use ensures that calcium sulphate is perfectly integrated into the winemaking process, without altering the aromas or structure of the final wine.

It is important to note that this practice is reserved for the production of liqueur wines. Other types of wine, such as still or sparkling wines, cannot benefit from this calcium sulphate adjustment under current regulations.

Is calcium sulphate also used in the food sector?

Apart from oenology, calcium sulphate has many uses in the food industry. It is commonly used to make tofu, where it acts as a coagulating agent, converting soya milk to firm blocks.

It is also found in dairy products, to improve their texture, and in canned vegetables, where it helps to preserve their firmness and freshness. Lastly, some cereal products use calcium sulphate to improve their structure and stability.

Whether in wine, food or even other industries, calcium sulphate (E516) demonstrates remarkable versatility, combining science and know-how to improve the products it accompanies.