Carbonated or "sparkling" water
Carbonated water that contains dissolved carbon dioxide gas.
The first sparkling water known to mankind was naturally carbonated water, water that picked up its bubbles from underground sources of carbon dioxide.
Examples of naturally carbonated waters are those from the original springs of Selters (from where the word "Seltzer" comes from), Perrier and Gerolsteiner Sprudel.
Naturally carbonated water has a lighter effervesence in comparison to artificially carbonated water, they are "fizzy" yet mild.
Joseph Priestley who discovered carbon dioxide also discovered the way to infuse water with it. He published his discovery in a paper (Impregnating water wth fixed air), in 1767.
A few years later Priestley's method was improved and Thomas Henry built the first carbonated water plant in Manchester, England where he produced "artificial Seltzer water".
Carbon dioxide is a gas with the chemical formula CO2, that is, one atom of carbon and two atoms of oxygen. It is the best known "greenhouse" gas and it is generated by many natural processes (such as breathing, combustion, volcanos and degassing from sedimentary rocks) as well as man-made sources (burning of fossil fuels).
A carbonated beverage has around 3.5 g of carbon dioxide per liter. That is 1 ⁄ 8 of an ounce per quart.
Carbon dioxide is dissolved in water under pressure, this takes place at a low temperature so that the water can dissolve more gas. The bottle is then capped and its contents remain pressurized.
When the bottle is opened pressure drops and the carbon dioxide is released from the solution as bubbles: "effervescence".
Types of Carbonated Water
Sparkling water is the name that cover all the varieties of carbonated water. It can include:
- Naturally carbonated mineral water
- Artificially carbonated water
- Seltzer water
- Club Soda
Club soda is a variety of carbonated water. It is water to which carbonation and potassium bicarbonate and/or potassium sulfate has been artificially added in order to enhance its flavor. It is very similar to seltzer water, but seltzer water does not include the added mineral content (and is very similar to unprocessed mineral water).
Verify the sodium content of Club Soda if you have high blood pressure issues, it contains added sodium to imitate the taste of mineral water
Bubbles, bite and taste
The allure of carbonated water is the oral sensation they provoke. The usual assumption is that the bubbles stimulate the inside of our mouths and tongue as the CO2 bubbles burst.
Wise (2013) ( 1 ) investigated the "carbonation bite" of sparkling water and confirms that the sensation is not mechanical but chemical: Wise tested carbonated water using a laboratory where they could adjust the atmospheric pressure of the room, and found that subjects gave the same carbonation bite rating to water drank at normal atmospheric pressure (which allows bubbles to form) and to water drank at 2 atmosphers (which does not allow bubbles to form).
In other words the bite was not caused by bubbles, but by the reaction of the carbon dioxide with the tongue, which produces carbonic acid.
Other similar experiments in which bubble formation was prevented provoked the same mouth-burn, pricking, bite, tingling sensations in the subjects. Clearly the mechanism is chemical.
In another test Wise created streams of air bubbles around the tongue and found that it did not induce a bite sensation in un-carbonated solutions but it enhanced the carbonation bite in midly tart carbon dioxide solutions.
So bubbles even though not necessary for feeling the "bite", enhance its sensation.
The sensations described are also dependent on the temperature and the carbon dioxide content of the drink: Harper and McDaniel (1993) ( 2 ) had a trained panel taste sparkling water with different carbonation levels at different temperatures and found that increasing CO2 levels increased the use of descriptors such as sour, bitter, bubbly, bubble size, feeling, bite, numbing. Warmer drinks were rated higher for bubble size and bubble sound while cooler drinks rated higher on bite, burn, cooling and numbing.
Does Sparkling water cause weight gain?
The bubbles make you hungrier
A study by Eweis (2017) ( 3 ) gave rats different types of carbonated beverages to drink and meaured their release of the "hunger hormone" ghrelin. A control group was given degassed carbonated drinks (flat sodas). They ran a similar test in 20 healthy men. They found that:
- The rats drinking carbonated beverages "gain[ed] weight at a faster rate than controls on regular degassed carbonated beverage or tap water"
- Weight gain in the rats was due to "elevated levels of the hunger hormone ghrelin and thus greater food intake in rats drinking carbonated drinks compared to control rats".
- In humans, the levels of ghrelin increased in those drinking carbonated beverages compared to controls drinking flat sodas.
The authors concluded that "These results implicate a major role for carbon dioxide gas in soft drinks in inducing weight gain and the onset of obesity via ghrelin release and stimulation of the hunger response."
This study is at odds with a previous study (Wakisaka 2012) ( 4 ) who also investigated the effects of carbonated water on gastric and apetite sensation in young healthy women.
Wakisaka concluded that "Carbonated Water may induce a short-term, but significant, satiating effect ...".
It is evident that further research is required on the effects that carbon dioxide has on hunger.
Salt Rich Carbonated Water and heart disease
Schoppen (2004) ( 5 ) studied postmenopausal women who drank 1 liter per day of carbonated water which was rich in sodium, chloride and bicarbonate and compared them to a control groip that drank plain water. The carbonated water drinkers' cardiovascular disease indicators improved:
- Total cholesterol values dropped by 6.8%
- LDL-cholesterol (or "bad" cholesterol) fell by 14.8%
- HDL-cholesterol (or "good" cholesterol) increased by 8.7%
- Fasting glucoe concentration decreased by 6.7% (blood sugar is an indicator of insulin resistance).
Schoppen concluded that sodium-rich carbonated water prevents Cardiovascular disease and metabolic syndrome.
Sodium Rich Sparkling Water and its effect on Blood Pressure
The interesting part of Schoppen's study (5) is that high-sodium diets are associated with hypertension (high blood pressure), but in this case blood pressure was not affected. The study believes that the bicarbonate ions had a beneficial effect. Furthermore this carbonated water also contained " 39 times more potassium than the control water; potassium counteracts some of the negative effects of sodium."
Santos (2010) ( 6 ) also investigated the effect of sodium-rich carbonated water on blood pressure and found that it had no effect on blood pressure either.
Carbon dioxide gas dissolved in water at a low concentrations (between 0.2 and 1%) form carbonic acid H2CO3. It is the carbonic acid that gives carbonated waters a slightly acidic flavor. Its acid value (measured as pH) lies between 3 and 4 so it is roughly as acidic as an orange juice or an apple juice.
The presence of sodium bicarbonate (as in Schoppen's study) would neutralize part of the carbonic acid, reducing acidity.
Acid and Bone Health
Ogur (2007) ( 7 ) found that consumption of cola drinks is associated with a decrease in the bone mineral denisty, it has not been reported in other carbonated beverages. Cola sodas are acidified with phosphoric acid as a preservative, which may leach calcium from the bones.
Tooth enamel erosion
Acidic foods and beverages can cause erosion of the dental enamel, leading to cavities. The critical level is a pH value of around 4. Below that value dental erosion can occur.
Neutral pH is 7, and as the value decreases acidity increases.
Avanija (2016) ( 8 ) classifies beverages based on their acidity and their erosive power. The table below shows some selected beverages:
- Minimally erosive (pH above 4.0)
- Erosive (pH above 3 - 3.99)
- Extremely erosive (pH below 3.0)
Minute Maid Lemonade
Gatorade Rain Lime
Mountain Dew Reg.
San Pellegrino sparkling
Cola drinks have a pH of around 2.75, which is roughly 100 times more erosive than carbonated water with a pH of 4.75 (the pH scale is not lineal, it is logarithmic so a difference of 1 unit means a difference of 10 times in terms of acidity).
Parry (2001) ( 9 ) studied how still and sparkling mineral waters eroded extracted human teeth. They found that "Dissolution levels with all of the mineral waters were very low and for several still waters were undetectable. Sparkling mineral waters showed slightly greater dissolution than still waters, but levels remained low.".
Another effect was that mineral waters (that is, waters that contain dissolved minerals) with their mineral ions "may positively influence any dissolution processes at the tooth surface."
Some bottled seltzers are flavored with citric acid (an acid which is found in oranges, limes and lemons) which makes them more acidic and can lower their pH below the threshold and cause damage to tooth enamel.
Adding a slice of lemon to your glass of carbonated water will not increase acid levels so it is a safe way to add flavor to your drinks.
Cite this article:
A. Whittall. ©2018. Sparkling or Still Water?. Patagonia Wellness, 11 Oct. 2018. http://www.patagoniawellness.com/health/sparkling-or-still-water.html
Subject: Sparkling or Still Water?. The pros and cons of drinking carbonated or plain still water
References and Further Reading
(1) Paul M. Wise , Madeline Wolf, Stephen R. Thom, Bruce Bryan (2013). The Influence of Bubbles on the Perception Carbonation Bite. Published: August 21, 2013https://doi.org/10.1371/journal.pone.0071488
(2) Harper Steven, McDaniel Mina (1993). Carbonated Water Lexicon: Temperature and CO2 Level Influence on Descriptive Ratings. Oregon State University Agricultural Experiment Station Technical Paper No. 10,016.
(3) Eweis, Dureen Samandar et al. (2017). Carbon dioxide in carbonated beverages induces ghrelin release and increased food consumption in male rats: Implications on the onset of obesity. Obesity Research & Clinical Practice , Vol.11:5 , 534 - 543 DOI: https://doi.org/10.1016/j.orcp.2017.02.001
(4) Shiori Wakisaka et al., (2012). The effects of Carbonated Water upon Gastric and Cardiac activities and fullness in healthy young women. J Nutr Sci Vitaminol 58, 333-338, 2012
(5) Stefanie Schoppen et al., (2004). A Sodium-Rich Carbonated Mineral Water Reduces Cardiovascular Risk in Postmenopausal Women. The Journal of Nutrition, Vol 134:5, 1 May 2004, 1058-1063, https://doi.org/10.1093/jn/134.5.1058
(6) Santos A, Martins MJ, Guimaraes JT, Severo M, Azevedo I, (2010). Sodium-rich carbonated natural mineral water ingestion and blood pressure, Rev Port Cardiol. 2010 Feb;29(2):159-72./p>
(7) Ogur R, et al., (2007). Evaluation of the effect of cola drinks on bone mineral density and associated factors. Basic Clin Pharmacol Toxicol. 2007 May;100(5):334-8. doi: 10.1111/j.1742-7843.2007.00053.x
(8) Avanija Reddy et al., (2016). The pH of beverages in the United States. April 2016 Vol 147:4, 255-263 JADA
(9) Parry J, Shaw L, Arnaud MJ, Smith AJ., (2001). Investigation of mineral waters and soft drinks in relation to dental erosion. J Oral Rehabil. 2001 Aug;28(8):766-72