What Chemicals Are In Fizzy Drinks?

Kate Onissiphorou

by Kate Onissiphorou

14th September 2022

Fizzy drinks are sweet, bubbly beverages that contain chemicals such as phosphoric acid, along with carbon dioxide and various additives, artificial colours, and flavours.

The carbonated water in fizzy drinks (made when carbon dioxide and water react) is responsible for the beverage’s characteristic bubbles. As the dissolved carbon dioxide evaporates when the pressure is released, bubbles are formed. The bubbles themselves contribute to the unique flavour and appearance of fizzy drinks.

Other chemicals in fizzy drinks serve as preservatives, artificial colourings, and additional flavourings. The exact flavours vary depending on the brand and specific product, but they’re all artificial. Even in products that are technically the same, such as cola-flavoured fizzy drinks, there are subtle flavour differences between the different brands.

How are fizzy drinks made?

Companies that manufacture fizzy drinks follow standardised methods when making their products. They also use similar ingredients and machinery. 

Three glasses of fizzy drinks; orange, cola, and lemonade

There are two main methods of producing finished products from flavouring syrup. The first involves diluting the syrup with water. It’s then cooled before carbon dioxide is added and the solution is bottled or canned. The second method is slightly different because instead of diluting the syrup with water, a precise amount of syrup is added to each bottle before it’s filled with carbonated water.

Some fizzy drink fountain dispensers in restaurants have separate compartments for the syrup and carbonated water, which can either be automated or controlled manually. The latter allows for more customisation when it comes to taste and flavour.

The key ingredients of fizzy drinks

The most obvious identifier of fizzy drinks is the ‘fizz’ or bubbles that make a hissing sound when a bottle or soda can is opened. If the drink is shaken before it’s opened, the soda foam can overflow and spill. Hence, the main ingredient that easily identifies fizzy drinks is the dissolved gas that creates the bubbles. 

Cola being poured from a can into a glass filled with ice

Here are the key ingredients of fizzy drinks:

  • Water – this serves as the solvent for the other ingredients
  • Carbon dioxide – CO2 is added to water under pressure to make carbonated water
  • Fructose corn syrup – this is a viscous liquid with a high sugar (fructose) concentration. It can either be diluted with carbonated water or added in precise amounts to each container
  • Colour – for example, caramel colour is present in cola drinks, and other fizzy drinks have different artificial colourings, such as orange and green
  • Caffeine – caffeine is a common ingredient in many fizzy drinks, especially cola. It’s thought to cause some level of addiction to soft drinks
  • Phosphoric acid – this is mainly added as a preservative to prevent the growth of bacteria and fungi. It’s also responsible for the characteristic tangy taste
  • Citric acid – chemically identical to the chemical found in citrus fruits, citric acid acts as a preservative and gives fizzy drinks their fruity flavour. It should not be confused with ascorbic acid, which is vitamin C
  • Sodium benzoate and potassium sorbate – these are inorganic salts that are commonly added as preservatives

Why is carbon dioxide used in fizzy drinks?

When carbon dioxide is added to water under high pressure, it dissolves to form carbonated water. Fructose syrup and other ingredients are then mixed with the carbonated water to produce fizzy drinks.

Carbon dioxide was originally added as a preservative to prevent the sugary content from spoiling and to make the drink look more interesting. It also contributes to the unique taste of fizzy drinks. 

Carbon dioxide is highly soluble in water and is safe when compared to other types of gases that can also produce fizz or bubbles.

Is carbon dioxide in fizzy drinks bad for you?

Carbon dioxide itself is safe as a drinks additive; it does not cause any serious or long-term health issues. 

When carbon dioxide is dissolved in water, it temporarily forms a weak acid, known as carbonic acid (H2CO3). This acid contributes to the tingly sensation on your tongue when you consume fizzy drinks. The carbon dioxide and its resultant acid don’t inflict any real harm, although they can be easily burped.

How much carbon dioxide is in fizzy drinks? 

The level of dissolved carbon dioxide in water, otherwise known as carbonation, is measured in terms of either ‘volumes’ or grams per litre. 

A typical fizzy drink has a carbon dioxide content of between six and eight grams per litre, or three to four volumes. A volume of carbonation is equivalent to one litre of carbon dioxide in one litre of water.

What acid do fizzy drinks contain?

Fizzy drinks contain several types of acid, depending on the brand and specific product. The most common type of acid in fizzy drinks is carbonic acid, which is a weak acid formed by the reaction of carbon dioxide with water. 

The second most common acid in fizzy drinks is phosphoric acid, which serves as a preservative. This is followed by citric acid, which acts as both a preservative and flavouring.

Are fizzy drinks harmful?

Fizzy drinks are considered to be harmful to your health, both in the short- and long-run. Just like other sugary drinks, they can cause type II diabetes when consumed over a long period. The high sugar content also leads to tooth decay, while the acids in the drink can also weaken tooth enamel.

Can of cola surrounded by white sugar cubes

The phosphoric acid in fizzy drinks competes with calcium absorption, which may lead to osteoporosis. Although consuming too many fizzy drinks can increase the risk of liver disease, it’s not necessarily worse than alcohol, which can cause liver cancer.


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