Carbonated water (also known as club soda, soda water, sparkling water, seltzer, fizzy water, or water with gas) is water into which carbon dioxide gas under pressure has been dissolved. This process, known as carbonation, is a process that causes the water to become effervescent (form bubbles). Most carbonated water is sold in ready to drink bottles as mineral water and carbonated beverages such as soft drinks. However, it is rather easy to prepare at home with soda makers.
Whether homemade or store-bought, soda water may be identical to plain carbonated water or it may contain a small amount of table salt, sodium citrate, sodium bicarbonate, potassium bicarbonate, potassium citrate, potassium sulfate, or disodium phosphate, depending on the bottler. These additives are often included to emulate the slightly salty taste soda water developed years ago from first using them as preservatives. Naturally occurring processes also produce effervescent mineral water similar to carbonated water in artesian wells, such as in Mihalkovo in the Bulgarian Rhodope Mountains, in Medžitlija in Macedonia, or most notably in Selters in the German Taunus mountains.
By itself, carbonated water appears to have little impact on health. While carbonated water is somewhat acidic, this acidity is quickly neutralized by saliva. It can increase symptoms of bloating and gas due to the release of carbon dioxide in the digestive tract. It does not appear to have an effect on acid reflux. There is tentative evidence that carbonated water may help with constipation among people who have had a stroke. Some carbonated waters have added sodium, so they may be an issue for those on low-sodium diets.
Typical carbonated soft drinks such as colas do have health risks. Carbonated colas have a correlation with slightly decreased bone density in older women. Soft drinks are about 100 times more erosive to teeth than plain carbonated water.
Carbon dioxide gas dissolved in water at a low concentration (0.2–1.0%) creates carbonic acid. The acid gives carbonated water a slightly tart flavor. The pH level between 3 and 4 is between apple juice and orange juice in acidity, but much less acidic than the acid in the stomach. The human body robustly maintains pH equilibrium vi aacid–base homeostasis and will not be affected by consumption of plain carbonated water. If an alkaline salt, such as sodium bicarbonate, potassium bicarbonate, or potassium citrate is added to the water, its acidity is reduced.
The amount of a gas like carbon dioxide that can be dissolved in water is described by Henry’s Law. Water is chilled, optimally to just above freezing, in order to permit the maximum amount of carbon dioxide to dissolve in it. Higher gas pressure and lower temperature cause more gas to dissolve in the liquid. When the temperature is raised or the pressure is reduced (as happens when a container of carbonated water is opened), carbon dioxide comes out of solution, in the form of bubbles. This is known as effervescence.
Many alcoholic drinks, such as beer, wine and champagne, were carbonated by fermentation for centuries. In 1662 Christopher Merret created ‘sparkling wine.’ In 1750, Frenchman Gabriel François Venel produced artificial carbonated water for the first time. In 1767, Joseph Priestley discovered a method of infusing water with carbon dioxide when he suspended a bowl of water above a beer vat at a local brewery in Leeds, England. The air blanketing the fermenting beer—called ‘fixed air’—was known to kill mice suspended in it. Priestley found water thus treated had a pleasant taste, and he offered it to friends as a cool, refreshing drink. In 1772, Priestley published a paper titled ‘Impregnating Water with Fixed Air’ in which he describes dripping ‘oil of vitriol’ (sulfuric acid) onto chalk to produce carbon dioxide gas, and encouraging the gas to dissolve into an agitated bowl of water. Priestley referred to his invention of soda water as being his ‘happiest’ discovery.
In the late eighteenth century, J. J. Schweppe of Switzerland developed a process to manufacture carbonated mineral water, based on the process discovered by Priestley, founding the Schweppes Company in Geneva in 1783. In 1792 he moved to London to develop the business there. In 1799 Augustine Thwaites founded Thwaites’ Soda Water in Dublin. A London Globe article claims that this company was the first to patent and sell ‘Soda Water’ under that name. Modern carbonated water is made by passing pressurized carbon dioxide through water. The pressure increases the solubility and allows more carbon dioxide to dissolve than would be possible under standard atmospheric pressure. When the bottle is opened, the pressure is released, allowing the gas to come out of the solution, forming the characteristic bubbles.
In the United States, carbonated water was known as ‘soda water’ until World War II, due to the sodium salts it contained. These were added as flavoring and acidity regulators with the intent of mimicking the taste of natural mineral water. During the Great Depression, it was sometimes called ‘two cents plain,’ a reference to its being the cheapest drink at soda fountains (i.e. without the addition of three cents-worth of flavored syrup). In the 1950s, terms such as ‘sparkling water’ and ‘seltzer water’ gained favor. The term ‘seltzer water’ is a genericized trademark that derives from the German town Selters, which is renowned for its mineral springs. Naturally carbonated water has been commercially bottled and shipped from this town since the 18th century or earlier.
Generally, seltzer water has no added sodium salts, while club soda still retains some of the sodium salts that once were used. The term ‘Seltzer water’ is virtually unknown in Britain and most Commonwealth countries, although Australians of a certain age remember Selza Saline powder in metal tins with lids which had to be opened for each use with the back of a spoon, sold during the 1950s. In many parts of the US, soda has come to mean any type of sweetened, carbonated soft drink. In the United Kingdom and Canada today, drink mixers sold as soda water or club soda contain bicarbonate of soda, which gives them a specific flavor and differentiates them from carbonated water. It is popularly used for drinks such as whisky and soda and Campari soda.
Carbonated water changed the way people drank. Instead of drinking liquor straight/neat (without a mixer), soda water and carbonated soft drinks helped dilute alcohol, and made having a drink more socially acceptable. Whisky and sodas can be seen in many British TV series and films from the 1960s and earlier. Only a small amount of soda water is added; a ‘splash’, and ‘Scotch and a splash’ was a common bar order. Whisky and soda was commonly drunk without ice in the UK. The soda siphon, or seltzer bottle — a glass or metal pressure vessel with a release valve and spout for dispensing pressurized soda water — was a common sight in bars and in early- to mid-20th century homes where it became a symbol of middle-class affluence.
Social drinking changed with the counterculture movement of the 1970s and the arrival of new bottled and canned beverages in the 1980s, and soda water has declined in popularity. Soda siphons are still bought by the more traditional bar trade and are available at the bar in many upmarket establishments, but in the UK there are now only two wholesalers of soda-water in traditional glass siphons, and an estimated market of around 120,000 siphons per year (2009). Worldwide, preferences are for beverages in recyclable plastic containers. Home soda siphons and soda water are enjoying a renaissance in the 21st century as retro items become fashionable.
The gasogene (or gazogene, or seltzogene) is a late Victorian device for producing carbonated water. It consists of two linked glass globes: the lower contained water or other drink to be made sparkling, the upper a mixture of tartaric acid and sodium bicarbonate that reacts to produce carbon dioxide. The produced gas pushes the liquid in the lower container up a tube and out of the device. The globes are surrounded by a wicker or wire protective mesh, as they have a tendency to explode.
In 1872, British soft drink maker Hiram Codd of Camberwell, London, designed and patented the Codd-neck bottle, designed specifically for carbonated drinks. The Codd-neck bottle encloses a marble and a rubber washer/gasket in the neck. The bottles were filled upside down, and pressure of the gas in the bottle forced the marble against the washer, sealing in the carbonation. The bottle was pinched into a special shape to provide a chamber into which the marble was pushed to open the bottle. This prevented the marble from blocking the neck as the drink was poured.
Soon after its introduction, the bottle became extremely popular with the soft drink and brewing industries mainly in Europe, Asia and Australasia, though some alcohol drinkers disdained the use of the bottle. One etymology of the term ‘codswallop’ originates from beer sold in Codd bottles, though this is generally dismissed as a folk etymology. The bottles were regularly produced for many decades, but gradually declined in usage. Since children smashed the bottles to retrieve the marbles, they are relatively rare and have become collector items, particularly in the UK. The Codd-neck design is still used for the Japanese soft drink Ramune and in the Indian drink called Banta.
Modern soda makers or soda carbonators are appliances that carbonate water with multiple-use carbon dioxide canisters. Soda makers may reach a higher level of carbonation than home soda siphons. A variety of systems are produced by manufacturers and hobbyists. The commercial units may be sold with concentrated syrup for making flavored soft drinks. One major producer of soda carbonators is SodaStream. Their products were popular during the 1970s and 1980s in the United Kingdom, and are associated with nostalgia for that period and have experienced a comeback since.