Mineral water is produced from rainwater. The water penetrates into the ground and seeps away. On its long journey deep underground, it passes through layers of rock that purify and filter the water. They also enrich it with valuable ingredients such as minerals and trace elements. Depending on the layer of rock, this happens in different concentrations and compositions. Besides magnesium from dolomite, salt deposits release sodium, rocks rich in gypsum provide sulphate and rocks rich in lime provide calcium and hydrogen carbonate. Especially in volcanic regions, the water (H₂O) is enriched with natural carbon dioxide (CO₂), which produces carbonic acid (H₂CO₃). The mineral water is stored in protected water deposits that prevent contamination. From region to region, the layers of rock through which the water passes differ, as do the ingredients it absorbs.