Mined sulfur is heated into a liquid and used to protect wine from oxidizing.
The same method has been used to protect wine from oxidization for centuries. In grape juice or wine, sulfur dioxide reacts with water molecules to form sulfites. In solution, all forms act the same way, releasing sulfur dioxide. There is strong evidence that sulfur dioxide was used by Egyptians and has been in regular use since Roman times. European winemakers have used sulfur dioxide to prevent wine spoilage for centuries.