Solid carbon dioxide, or dry ice, is soluble in water, but its solubility is influenced by several factors including temperature, partial pressure of CO2, pH, and metal impurities. When dry ice is added to water, much of the carbon dioxide escapes as gas, but some dissolves, resulting in carbonated water. However, dry ice is typically contaminated with compressor oils, making it unsuitable for creating drinkable sparkling water. For carbonation, food-grade CO2 is recommended. Homebrewers often carbonate beer by adding corn sugar or fresh sterile wort, a method known as krausening, to achieve desired carbonation levels. Uncontrolled fermentation can lead to popped bottles and unintended alcohol production.