Gypsum, also known as calcium sulfate, is a natural mineral that is commonly used in winemaking to adjust acidity, improve mouthfeel, and prevent haze. It is a safe and effective product that has been used for centuries by winemakers.
 
Gypsum works by adding calcium ions to the wine. Calcium ions bind to tartaric acid, the primary acid found in grapes, to form calcium tartrate. Calcium tartrate is a precipitate that settles to the bottom of the wine and can be removed by filtration. This can help to reduce the acidity of the wine.
 
Gypsum can also improve the mouthfeel of wine by making it fuller and rounder. It can also help to prevent haze by binding to proteins and other colloidal particles in the wine. These particles are responsible for making the wine hazy.
 
Gypsum is a good choice for acid reduction and mouthfeel improvement in both white and red wines. It can also be used to prevent haze in white wines.