Whether homemade or store-bought, soda water may be identical to plain carbonated water or it may contain a small amount of table salt, sodium citrate, sodium bicarbonate, potassium bicarbonate, potassium citrate, potassium sulfate, or disodium phosphate, depending on the bottler. These additives are often included to emulate the slightly salty taste soda water developed years ago from first using them as preservatives. Naturally occurring processes also produce effervescent mineral water similar to carbonated water in artesian wells, such as in Mihalkovo in the Bulgarian Rhodope Mountains, in Medžitlija in Macedonia, or most notably in Selters in the German Taunus mountains.