since carbon dioxide is tasteless, why does carbonated water still have an identifiable “taste” many days after it’s been opened, when the bubbles have long since disappeared?

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since carbon dioxide is tasteless, why does carbonated water still have an identifiable “taste” many days after it’s been opened, when the bubbles have long since disappeared?

In: 16

Carbonated water is supersaturated with CO2, more than the water can naturally hold at atmospheric pressure. Releasing the pressure by opening the bottle or can will start the bubbling process and allowing the excess CO2 to escape. However, the bubbling only continues until the water isn’t supersaturated. It reaches an equilibrium where there is still some CO2 in the water.

Chemical reactions rarely consume all of the reagents in them. Even after the bubbles stop, there’s still a bit of carbonic acid left in the drink, which is what makes carbonated water taste different from regular water.

A quick google search finds that at 1 atmosphere pressure, at 300 K temperature, the pH of a saturated solution of C02 in water is about 3.6.

Since pure water has a pH of 7, the flat carbonated water will be more acidic.

Like other people have mentioned, the acidity is caused by carbonic acid.

At higher pressures, the pH can go below 3.

Since pH is measured on a log10 scale, the pH = 3 is a lot more acidic than pH = 3.6 (about 4X more).

Thanks for this question, it was a fun search.

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since carbon dioxide is tasteless, why does carbonated water still have an identifiable “taste” many days after it’s been opened, when the bubbles have long since disappeared?

In: 16

Carbonated water is supersaturated with CO2, more than the water can naturally hold at atmospheric pressure. Releasing the pressure by opening the bottle or can will start the bubbling process and allowing the excess CO2 to escape. However, the bubbling only continues until the water isn’t supersaturated. It reaches an equilibrium where there is still some CO2 in the water.

Chemical reactions rarely consume all of the reagents in them. Even after the bubbles stop, there’s still a bit of carbonic acid left in the drink, which is what makes carbonated water taste different from regular water.

A quick google search finds that at 1 atmosphere pressure, at 300 K temperature, the pH of a saturated solution of C02 in water is about 3.6.

Since pure water has a pH of 7, the flat carbonated water will be more acidic.

Like other people have mentioned, the acidity is caused by carbonic acid.

At higher pressures, the pH can go below 3.

Since pH is measured on a log10 scale, the pH = 3 is a lot more acidic than pH = 3.6 (about 4X more).

Thanks for this question, it was a fun search.