Sparkling water, also known as carbonated water, is simply water that contains dissolved carbon dioxide gas. This infusion of gas, either occurring naturally from mineral springs or added artificially under pressure, gives the water its characteristic effervescence and bubbles. When subjected to heat, particularly boiling, sparkling water undergoes significant changes, transforming it from its original bubbly state.
The Escape of Carbon Dioxide
The primary characteristic of sparkling water is the dissolved carbon dioxide, which is highly sensitive to temperature changes. Gas solubility in liquids generally decreases as temperature increases. As sparkling water begins to heat, even before reaching a full boil, the dissolved carbon dioxide becomes less soluble and starts to come out of solution rapidly. This phenomenon is visible as tiny bubbles forming on the bottom and sides of the pot, often appearing before the water visually boils.
As the temperature continues to rise towards the boiling point, the remaining dissolved gas is almost completely expelled from the water. Boiling ensures that nearly all the carbon dioxide escapes into the atmosphere, leaving the water entirely “flat.” This process is a physical change, meaning the carbon dioxide simply leaves the water, rather than undergoing a chemical transformation that would alter the water’s fundamental composition beyond its gas content.
Impact on Dissolved Minerals
Many sparkling waters, especially natural mineral waters, contain various dissolved minerals like calcium, magnesium, and bicarbonates. When sparkling water is boiled, the heat can cause some of these dissolved minerals to precipitate out of the solution. This precipitation often results in solid deposits, commonly known as limescale, which can be observed at the bottom or on the sides of the cooking vessel.
The formation of limescale primarily involves calcium carbonate and magnesium carbonate, which become less soluble at higher temperatures. As carbon dioxide is released during heating, the chemical equilibrium shifts, promoting the formation of these less soluble mineral compounds. The extent of mineral precipitation depends on the initial mineral content of the sparkling water, with waters higher in calcium and magnesium exhibiting more noticeable changes.
Resulting Taste and Texture
Boiling sparkling water alters its taste and texture. The complete loss of carbonation means the water will no longer have its signature effervescence, feeling “flat” in the mouth. This absence of bubbles changes the mouthfeel from a prickly sensation to that of still water.
The precipitation of minerals during boiling can subtly influence the taste. While the water becomes still, the altered mineral profile might impart a slightly different flavor compared to unboiled still water or even regular tap water that has been boiled. Some may perceive it as having a “harder” taste or a distinct mineral note due to the concentrated remaining minerals.