Sparkling or still? Water with or without carbonation

Still or sparkling water – According to VerbraucherFenster Hessen, most Germans drink sparkling mineral water, whilst others prefer still water. The short answer to the question of which is better is that, for healthy people, sparkling water is generally just as safe as still water. There are exceptions in cases of heartburn and a sensitive stomach. Here you can find out what carbonation does to your teeth, stomach and thirst – and what the terms on the label mean.

What exactly is carbon dioxide?

Carbon dioxide (CO₂) dissolves in water to form carbonated water. This occurs naturally, for example, in regions with a volcanic or geologically active history, where CO₂ rises from deeper layers of the earth into the groundwater. In Germany, mineral water is the second most commonly consumed drink after coffee: according to the Association of German Mineral Springs, each person drinks around 125 litres a year.

The level of fizz in water varies: there are no legal requirements for ‘Medium’ or ‘Classic’; the carbon dioxide content can range from around 2.9 to 5.2 g per litre. Carbonated water is usually slightly acidic; still mineral water is not necessarily pH-neutral either, depending on its mineral content.

What it says on the label

The Mineral and Table Water Regulations set out precisely what a natural mineral water with carbonation must be called:

• ‘Natural carbonated mineral water’: After bottling, it contains the same amount of naturally occurring carbon dioxide as it did at the spring outlet and naturally releases a perceptible amount of it.
• “enriched with carbon dioxide from its own spring”: It contains more carbon dioxide from the same spring source than is present at the spring outlet.
• ‘carbonated’: The carbon dioxide added comes from a source other than the original one.

Natural mineral water may only be sold if it has been officially certified. Table water, on the other hand, is water that contains certain authorised ingredients, such as natural mineral water, drinking water, seawater or salts; if carbon dioxide has been added, the label must indicate this. Our Still and Sparkling varieties are labelled as ‘table water’.

Does carbon dioxide damage your teeth?

According to current scientific knowledge, ordinary sparkling mineral water is not considered harmful to tooth enamel. Carbon dioxide is a weak acid with a very low erosive effect; sugary or acidic drinks such as cola, lemonades or energy drinks are a far greater cause for concern.

A laboratory study by the University of Birmingham measured this using extracted teeth: sparkling mineral waters dissolved slightly more tooth substance than still waters, but about a hundred times less than the soft drinks used for comparison. When the sparkling water was de-carbonated, the figure fell – but overall it remained low, suggesting that carbon dioxide itself does not appear to be a significant factor. Calcium in the water further slowed down the dissolution process. Important: these were laboratory experiments, not measurements taken in the mouth.

Stomach and digestion: For those who prefer to drink quietly

When you drink sparkling water, carbon dioxide enters the body and has to be expelled again: some of it is absorbed into the bloodstream via the intestines and exhaled through the lungs, whilst the rest is released through burping and flatulence. This is generally harmless.

The situation is different for people who are prone to heartburn: when burping, stomach acid can enter the oesophagus and trigger heartburn. For those with a sensitive stomach, too, still or lightly carbonated water is preferable.

Conversely, there is evidence of benefits for certain symptoms: in a small Italian study, 21 people with functional dyspepsia and constipation drank either sparkling water or tap water for around 15 days. In the sparkling water group, the symptom scores for dyspepsia and constipation improved. This is a very small group of people with these symptoms – the findings cannot be generalised to everyone.

Thirst: Does sparkling water quench it better?

It certainly feels that way. In experiments at the Monell Chemical Senses Centre, adults who had gone more than twelve hours without food or drink first drank 400 ml of a test drink, followed by as much still water as they wanted. The cold temperature and the fizz of the carbon dioxide increased a drink’s thirst-quenching effect by up to 50 per cent. When participants were asked to estimate the amount they had drunk, they estimated that cold and fizzy drinks amounted to around 22 per cent more.

Two caveats: two of the co-authors were employed by a drinks manufacturer. And ‘feeling more thirsty’ does not mean that the body is actually taking in more water. People who do not feel very thirsty – such as many older people – should still pay attention to the amount they drink.

Why mineral water tastes different

Before rainwater becomes mineral water, it seeps many metres through the ground and collects in underground reservoirs, sometimes several hundred metres deep. As it passes through various layers of rock, it is filtered and absorbs minerals. Depending on the region, the type and quantity of minerals vary – and so does the taste: mineral water can taste salty, sour or bitter. The carbon dioxide adds to the flavour, as it makes the water slightly sour.

Incidentally, in the laboratory study carried out in Birmingham, it was the minerals – particularly calcium – that slowed down the loss of tooth structure.

Sparkling water in the kitchen

Sparkling water isn’t just for drinking. VerbraucherFenster Hessen lists several ways it can be used:

• Steaming and frying: Vegetables steamed in mineral water retain their colour and stay crisp. Fish and meat can be fried in a non-stick frying pan with a little sparkling water, without any fat – the base should be just barely covered.
• Creamy desserts: Quark stirred until smooth with sparkling water instead of milk turns out particularly light and creamy, as do waffles and mousses.
• Light and fluffy batter: Using some mineral water instead of milk makes pancakes, spaetzle, scrambled eggs or omelettes lighter and fluffier. However, it does not completely replace baking powder in cake batter.
• Yeast dough: Mineral water can improve the texture of the dough and result in a light crumb; however, this does not usually allow the amount of yeast to be reduced significantly.

When doing sport: with or without?

According to the Consumer Advice Centre, water is often sufficient for shorter training sessions; it is recommended to drink one or two glasses about half an hour before training. It does not specify whether the water should be still or sparkling. Anyone who experiences burping or stomach discomfort whilst running should follow the advice for sensitive stomachs: choose drinks with little or no carbonation. After exercise, mineral water is just as suitable as diluted fruit or vegetable juices for replenishing fluids and electrolytes. Read more in ‘Electrolytes no sugar’.

Another advantage: shelf life

Carbon dioxide can inhibit the growth of certain microorganisms and thus helps to preserve the water. If you drink still tap water: if it has been standing in the pipes for more than four hours, let it run until it cools down. In Germany, tap water is safe to drink.

You can find out how much you should drink in total – with or without fizz – in the guide ‘Drinking Water’. Our flavoured varieties are available both with and without fizz under ‘Flavoured Water’.

Frequently Asked Questions

Sources

1. VerbraucherFenster Hessen (Hesse Ministry): More than just H₂O: Everything you need to know about mineral water as a thirst-quencher, 29 June 26. verbraucherfenster.hessen.de
2. Federal Ministry of Justice (gesetze-im-internet.de): Mineral and Table Water Regulation (Min/TafelWV), last amended on 20 June 2023. gesetze-im-internet.de
3. Journal of Oral Rehabilitation (Parry J, Shaw L, Arnaud MJ, Smith AJ): Investigation of mineral waters and soft drinks in relation to dental erosion, 2001;28(8):766–772. doi.org
4. European Journal of Gastroenterology & Hepatology (Cuomo R et al.): Effects of carbonated water on functional dyspepsia and constipation, 2002;14(9):991–999. doi.org
5. PLOS ONE (Peyrot des Gachons C, Avrillier J, Gleason M et al.): Oral Cooling and Carbonation Increase the Perception of Drinking and Thirst Quenching in Thirsty Adults, 29 September 2016. doi.org
6. Institute for Quality and Efficiency in Health Care (IQWiG), gesundheitsinformation.de: Drinking enough in everyday life: tips and advice, 18 October 2023. gesundheitsinformation.de
7. Hessen Consumer Advice Centre: Specialised sports drinks are unnecessary, as at 27 April 2022. verbraucherzentrale-hessen.de
8. Bavarian Consumer Information System (Centre of Excellence for Nutrition, Ursula Haas): ‘What’s the truth about drinking enough?’ – The importance of drinking for human nutrition, 10 August 2021. vis.bayern.de
9. ACQUA REAPER: Product labels – Still and Sparkling, 26/08.
10. ACQUA REAPER: Product labels, as at 26 July.