Mouth-Watering Molecules

It takes approximately 1.3 million metric tons of CO2 (carbon dioxide) a year to quell Europe's craving for mineral water and other sparkling beverages. But what exactly happens when H2O joins forces with CO2?

Whether heat or sport-induced, sweating is a sign that your body needs water. Lots of water. When it comes to getting enough of the water of life, your body doesn't care whether or how much carbon dioxide is contained in your chosen beverage. Nevertheless, most people in Germany prefer their water with plenty of fizz. Consumption of mineral water increased more than 10-fold in Germany over the past 35 years to reach today's level of 125 liters per person per year – and that figure is growing. "In keeping with the long-standing trend toward fitness and taking care of your body, more and more people are coming to appreciate the purity of mineral water," commented Wolfgang Stubbe, head of the Association of German Mineral Sources (VDM).

"The population in Germany drank approximately 10 billion liters last year. Classic mineral water with a CO2 content of around six grams per liter accounted for approximately half of the total and mineral water with a reduced carbonic acid content made up another 40 percent. Still mineral water and 'near water' products containing added juice are increasing their (at present) minor share of the market.” Germany's appreciation for mineral water is also reflected in the vast range available. The water lovers' website www.mineralwaters.org gives 469 brands, for example. As far as the consumption of mineral water and number of available brands is concerned, Germany is topped only by the "acqua minerale"-loving Italians.

Water Craving
It takes approximately 1.3 million metric tons of CO2 (carbon dioxide) a year to quell Europe's craving for mineral water and other sparkling beverages. But what exactly happens when H2O joins forces with CO2? What makes plain water sparkling? Like all other gases, CO2's solubility in water depends on temperature and pressure. During manufacture, large quantities of CO2 are dissolved in the mineral water under high pressure. The dissolved gas reacts with the water (H2O) to form carbonic acid (H2CO3) (see diagram). The pressure drops suddenly when the bottle is opened. All of a sudden there are more CO2 molecules in the water than there is physical room for them. But because it takes a while for the CO2 molecules to escape the bond with the water molecules, the surplus CO2 is released only gradually and continues to sparkle and pop from the glass for quite a while in the form of tiny bubbles. The liveliness of the fizz mainly depends on the quantity of CO2 added to the water. The right quantity is entirely a matter of personal taste.

Pure CO2 needs to be produced in the first place before it can refresh parched throats in the form of carbonic acid. CO2 is produced at BASF's site in Ludwigshafen as a by-product of ammonia manufacturing. In the carbonic acid plant it is compressed to 20 bar, dried, purified, converted to liquid and filled into storage tanks. Alternatively, CO2 can also be solidified into dry ice, which is mainly used for refrigeration - for example by airlines such as Lufthansa, which use dry ice to keep food fresh during a flight.

Whatever its state (gas or ice): if it's intended for use in food (which accounts for approximately three-quarters of the market), only highly purified CO2 may leave our factory. Quality is strictly monitored using state-of-the-art technologies such as gas chromatography. CO2 that is not immediately required is stored in a tank in Ludwigshafen, ensuring that CO2 is always in supply even at the height of summer – helping mineral water and CO2 producers to meet their customers' refrigeration and refreshment requirements at all times.

Prospects
The bottled water market has now grown into a global industry, with sales of approximately $35 billion. Annual per capita consumption has been relatively low in the USA in recent years compared with Europe, amounting to around 45 liters. However, there's a burgeoning demand for European import brands, especially in upmarket restaurants. Several exclusive restaurants in New York already employ "water sommeliers" to help guests select the right water from an extensive mineral water menu.

Demand is growing not just for high-end water brands, however. The populations of many emerging economies are discovering the appeal of mineral water. Highly populated Asian countries, where imported brands are often a status symbol, are a promising source of income for the European water industry.

"The market for CO2 extends far beyond applications in mineral water," BASF expert Michael Hesser adds. "In addition to carbonization and food refrigeration, more than one-quarter of annual production is used for industrial applications or in fire extinguishers." With a 30 percent market share, Germany is by far the largest market for CO2 in western Europe, followed by France, Italy, Spain and the UK with market shares of 10 to 15 percent, respectively.

www.basf-ag.de