How do carbon dioxide bubbles give soft drinks their sparkle and tangy taste?

Carbon dioxide (CO₂) is added to soft drinks under high pressure to create their characteristic sparkle and tangy flavor. When the beverage is bottled, the high pressure forces the gas to dissolve into the liquid, a process governed by Henry’s Law.123

The "sparkle" or fizz occurs when the bottle is opened, causing the pressure to drop and the dissolved CO₂ to rapidly escape the solution as bubbles. Because water molecules have high surface tension, the gas relies on nucleation sites—microscopic rough spots or impurities—to cluster and form these visible bubbles.3

The "tangy" taste is primarily a result of the chemical interaction between the gas and the water. When CO₂ dissolves, a small portion reacts with water to form carbonic acid ($H_{2}C{O}_3$). This mild acidity contributes to the sharp, refreshing sensation associated with carbonated beverages. Additionally, the carbonation process helps preserve the drink by preventing spoilage.4123