Water Chemistry, oh boy.
As everyone on this forum no doubt knows, carbonation is simply dissolved CO2. What causes the CO2 to stay in suspension within the beer, is the factors based off of temperature, partial pressures, and solubility. Just like oxygen, CO2 tends to dissolve more readily, and at higher concentrations, into colder liquids.
Usings henry's law, and the ideal gas law (wikipedia if you need background on this information), we know that as the pressure in the bottle increases, due to the fermentation process producing CO2, the CO2 concentration in solution will increase. This is what causes your brew to become carbonated.
I told you that story to tell you this story: When CO2 dissolves in a liquid, it does not stay as CO2, but rather, it combines with a water molecule (H2O), to form carbonic acid, H2CO3. This acts as a buffer, which prevents pH changes in solution. If the pH raises (becomes more basic, rather than acidic), a hydrogen proton is cleaved off of the carbonic acid to form the following two chemicals: HA + HCO3 (where A is a base). However, when you add more carbonic acid, you also raise the pH, which in itself causes more free hydrogen atoms to float in the solution.
Now Hydrogen atoms are simply protons, and they are the only acid that exists. So that is to say, the more free hydrogen you have, the more acidic the solution is. This explains why you are able to taste "carbonation", you are simply tasting the extra acid the carbonation adds to the solution.