Carbon dioxide bubbles in a carbonated soft drink.

Carbonated water (also known as club soda, soda water, sparkling water, seltzer, or fizzy water) is water into which carbon dioxide gas under pressure has been dissolved, a process that causes the water to become effervescent.

Carbonated water is the defining ingredient of carbonated soft drinks. The process of dissolving carbon dioxide in water is called carbonation.

[edit] Etymology

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. In the 1950s, terms such as sparkling water and seltzer water gained favour. The term seltzer water is a genericized trademark that derives from the German town Selters , which is renowned for its mineral springs.^[1] Naturally carbonated water has been commercially bottled and shipped from this town since the 18th century or earlier.

In many parts of the United States, soda has come to mean any type of sweetened, carbonated soft drink.

[edit] Chemistry

Carbon dioxide and water form carbonic acid (H₂CO₃),^[2] which gives the water a slightly sour taste with a pH between 3 and 4.^[3] An alkaline salt, such as sodium bicarbonate, may be added to soda water to reduce its acidity.

Carbon dioxide dissolved in water at a low concentration (0.2%–1.0%) cannot be tasted by humans, but the sour flavor of carbonic acid can be. The addition of a sodium or postassium salt can neutralize some of the acidic flavor of drinks that are made with soda water.

[edit] Manufacture

[edit] Commercial

A modern bar soda "gun."

The process of dissolving carbon dioxide in water is called carbonation. Commercial soda water in siphons is made by chilling filtered plain water to 8 °C (46 °F), adding a sodium or potassium based alkaline compound such as sodium bicarbonate to reduce acidity, and then pressurising the water with carbon dioxide. The gas dissolves in the water, and a top-off fill of carbon dioxide is added to finally pressurise the siphon to approximately 120 pounds per square inch (830 kPa), some 30–40 psi (210–280 kPa) higher than is present in fermenting champagne bottles.

In most modern restaurants and drinking establishments, soda water is often manufactured on-site using devices known as carbonators. Carbonators use filtered water and pressurise it to approximately 100 psi (690 kPa) using mechanical pumps. The pressurised water is stored in stainless steel vessels and CO₂ is injected into the water producing carbonated water.

[edit] Home

Carbonated water can be made at home by use of a readily available 1 L (1.1 US qt) rechargeable soda-siphon and disposable one-shot screw-in carbon dioxide cartridges. A simple recipe is to chill filtered tap water in the fridge, add one quarter to one half a level teaspoon of sodium bicarbonate (baking soda) to the rechargeable soda-siphon, pour in the chilled water and add the carbon dioxide. A pH testing kit can be used to alter the amount of sodium bicarbonate per litre of carbonised water to neutralise acidity. The siphon should be kept in the refrigerator to preserve carbonation of the contents, and brought out for use, but many rechargeable soda-siphons are handsome objects in their own right, and are kept out for viewing on the drinks tray in many homes. Soda water made in this way tends not to be as 'gassy' as commercial soda water although chilling of the water before carbonation helps.

Carbonated water can be produced in the home by "charging" a refillable seltzer bottle by filling it with water and then adding carbon dioxide. 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 included to emulate the slightly salty taste of homemade soda water. The process can also occur naturally to produce carbonated mineral water, such as in Mihalkovo in the Bulgarian Rhodopes, or Medzitlija in Macedonia.

[edit] Soda siphons

An antique soda siphon circa 1922.

The gas pressure inside a siphon pressure vessel drives soda water up through a tube inside the siphon when a valve actuation lever at the top is depressed. Careful regulation of the valve lever is needed by the operator of the siphon to prevent pressurised soda water being released into the drink, which then splashes forcibly upwards, often soaking the operator.^{[citation needed]}

[edit] Use

Carbonated water is often drunk plain or mixed with fruit juice. It is also mixed with alcoholic beverages to make cocktails, such as Whisky and soda or Campari and soda. Flavoured carbonated water is also commercially available. It differs from sodas in that it contains flavors (usually sour fruit flavors such as lemon, lime, cherry, orange, or raspberry) but no sweetener.

Carbonated water is a diluent; It works well in short drinks made with whisky, brandy and Campari and in long drinks such as those made with vermouth. Soda water may be used to dilute drinks based on cordials such as orange squash. Soda water is a necessary ingredient in many cocktails, where it is used to top-off the drink and provide a degree of 'fizz'. Adding soda water to 'short' drinks such as spirits dilutes them and makes them 'long'. One report states that the presence of carbon dioxide in a cocktail may accelerate the uptake of alcohol in the blood, making both the inebriation and recovery phases more rapid.^[4]

The addition of carbonated water to dilute spirits was especially popular in hot climates and seen as a somewhat "British" habit. Adding soda water to quality Scotch whisky has been deprecated by whisky lovers, but was a popular lunchtime drink or early evening pre-dinner or pre-theatre drink until the late part of the 20th century. Pre-filled glass soda-siphons were sold at many liquor stores, a deposit was charged on the siphon, to encourage the return of the relatively expensive siphon for re-filling. In 1965, the deposit on a single soda-syphon in England was 7/6d (seven shillings and six pence).

[edit] History

In 1767, Englishman Joseph Priestley invented carbonated water when he first 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.^[5] 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 entitled 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.^[6]

In 1771, Swedish chemistry professor Torbern Bergman independently invented a similar process to make carbonated water. In poor health at the time yet frugal, he was trying to reproduce naturally-effervescent spring waters thought at the time to be beneficial to health.^{[citation needed]}

Carbonated water was introduced in the latter part of the 18th century, and reached Kolkata (formerly known as Calcutta), India in 1822.

In the late eighteenth century, J. J. Schweppe (1740–1821), a German-born naturalised Swiss watchmaker and amateur scientist developed a process to manufacture carbonated mineral water, based on the process discovered by Joseph Priestley, founding the Schweppes Company in Geneva in 1783. In 1792 he moved to London to develop the business there.

The soda siphon, or syphon — a glass or metal pressure vessel with a release valve and spout for dispensing pressurised 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.

Ányos Jedlik (1800–95), a Hungarian, invented consumable soda-water that continues to be a popular drink today. He also built an early carbonated water factory in Budapest, Hungary.^{[citation needed]} However, the process he developed at his factory for getting the CO₂ into the water remains a mystery to this day. After this invention, a Hungarian drink made of wine and soda water called "fröccs" (wine spritzers) was spread throughout several countries in Europe.

Since then, 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, thus forming the characteristic bubbles.

[edit] Social popularity, decline, and renaissance

Carbonated water changed the way people drank. Instead of drinking spirits neat, soda water, and later, carbonated soft drinks helped dilute alcohol, mitigating its harsh effects, and made having a drink more socially acceptable. Popping into a chum's house for hospitality from a "dash and a splash" - a whisky and soda - before going out to a social event was part of everyday activity in Britain as late as 1965.^{[citation needed]} Whisky and sodas can be seen in many British TV series and films from the 1960s and earlier and the soda siphon is ubiquitous in many movies made before 1970. Social drinking would change with the counter-culture anti-establishment movement of the 1970s, and the decline of soda water would begin from that point. Soda water's 'last hurrah' in Britain may have been the popular 1970s product, 'Soda Stream' A commercially available home bottling kit, which enabled purchasers to combine fruit syrups, and water, to create sparkling beverages. The famous advertising tag-line 'Get Bizzy With The Fizzy' spawned a series of similar expressions, such as 'Get Buzzy With the Fuzzy'.

The popularity of soda water has declined since the late 1980s as drinking habits and fashions change and new bottled or canned beverages arrive, but soda-siphons are still bought by the more traditional bar trade and available at the bar in many upmarket establishments. 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 to be distributed in recyclable plastic containers which may, or may not, be recycled.

Home soda siphons and soda water are enjoying a renaissance in the 21st century as retro items become fashionable. Contemporary soda siphons are commonly made of aluminium, although glass and stainless steel siphons are available. The valve-heads of today are made of plastic, with metal valves, and replaceable o-ring seals. Older siphons are in demand on on-line auction sites. Carbonated water, without the acidity regulating addition of soda, is currently seen as fashionable although home production (see below) is mainly eschewed in favour of commercial products.

[edit] Health effects

Carbonated water is a negligible cause of dental erosion; also known as acid erosion. While the dissolution potential of sparkling water is greater than still water, levels remain low: by comparison, carbonated soft drinks cause tooth decay at a rate of several hundred times that of regular sparkling water. De-gassing of carbonated water reduces its dissolution potential, but the total levels are still relatively low, suggesting that the addition of sugar into water, not its carbonation, is the main cause of tooth decay.^[7]

Intake of carbonated beverages has not been associated with increased bone fracture risk in observational studies, and the net effect of carbonated beverage constituents on the amount of calcium in the body is negligible,^[8] leaving carbonated water as harmless as regular water.^{[citation needed]} The phosphoric acid present in many soft drinks is what reduces bone density and increases bone fracture risk.

Carbonated water eases the symptoms of indigestion (dyspepsia) and constipation, according to a study in the European Journal of Gastroenterology and Hepatology.^[9]

A 2004 article in the Journal of Nutrition found that fizzy waters with higher sodium levels reduced cholesterol levels and the risk of cardiovascular problems in postmenopausal women.^[10]

[edit] See also

• Carbonation
• Carbonic acid
• Effervescence
• Premix and postmix
• Sodium bicarbonate
• Sodium carbonate
• Soft drink

[edit] References

[edit] External links

Wikimedia Commons has media related to: Mineral waters

• The Priestley Society
• Priestley's paper Impregnating Water with Fixed Air 1772
• Interview with one of New York City's last seltzer delivery men