Bicarbonate of cola

I always kind of wondered why some sodas had noticeable amounts of sodium listed on their nutrition information labels.  After all, they're not especially salty.  But Coca-cola has 45 mg of sodium per can.  Canada Dry Ginger Ale has about 55 mg, and Sprite has 65 mg.

It turns out that it has to do with the industrial carbonation process.  In natural carbonation (such as found in expensive fizzy alcoholic drinks), yeast will consume sugar and produce carbon dioxide, which slowly saturates the liquid, forming a soft, gentle bubble.  This process has some downsides for mass production, however-- it's slow, slightly imprecise, and tends to leave dead yeast at the bottom of the container.  It also doesn't work on drinks with sugar substitutes.

So instead, they simply take big vats of water and quickly force carbon dioxide into it under extreme pressure.  This creates a "sharper," "harsher" bubble, and has the benefits of consistency and speed.  However, it also produces a certain amount of carbonic acid, which, in sufficient quantities, can add a sour taste to the carbonated water.  So, to counteract this, many companies add a basic substance, to wit: baking soda, or sodium bicarbonate.  This naturally ups the sodium content in the soda, but that's not a big concern to the soda companies.  Or to most of the consumers, frankly-- it's not really a huge amount, just a couple percent of the US RDA per can.  But I did always wonder.