Chapter£±¡¡Basic of Water

¡¡When people think about good taste water, most people bring to mind about spring water from mountain and "mineral water" which is in bottled water. Tap water has changed from bad taste water which has chlorine to good taste water which is treated by advanced water treatment. However, the sales of bottled water rapidly increased even though the price is approximately more than 1000 times higher than tap water.
When looking at brands of mineral water at shops, there are lots of types such as printed famous location, and deep ocean water. There are more than 500 brands in bottled water which has been sold only in Japan. In bottled water, minerals are contained. However, most people don't know about the amount of minerals or its effects. The reason why people drink bottled water is because it seems better taste, safer, and more minerals compared to tap water. Then, what is the factors of good taste water?

¡¡According to "quality indication guideline for mineral water (bottled drinking water)" in Ministry of Agriculture, Forestry and Fisheries of Japan
¡ÊEstablished March, 1990. Revised February, 1995¡Ë

¡¡£±¡¥Natural water

The water is from specified underground water. The water is only treated by settling down, filtering, and heat sterilization. It must not be treated by chemical treatment.

¡¡£²¡¥Natural mineral water¡¡

In natural water, the water is from underground water which contains mineral salts (minerals) in underground. The water which has fizziness by natural CO2 is also included.

¡¡£³¡¥Mineral water¡¡

The source of the water is from natural mineral water. It is mixed with several sources natural mineral water which is conducted regulation of minerals, aeration to make stable of the quality.

¡¡£´¡¥Bottled water¡¡

Any drinkign water except the above 1, 2, and 3.

¡¡Please check which one is the water that you are drinking now.

¡¡It tends to regard that pure water which doesn't have anything is good taste, but it is not true. The factors for good taste water are contained minerals. Rain water is perused into grounds and rocks, and the water dissolves minerals (calcium and magnesium). The taste of water is because it contains minerals rather than just H2O pure water. In natural mineral water, more than 500 types of substances such as mineral and microorganisms are dissolved.
¡¡Moreover, there is soft water and hard water, and they are classified according to contained mineral contents (calcium, natrium, and kalium). Less than 100 mg hardness in 1 liter is classified as soft water, while more than 200 mg hardness in 1 liter is hard water. The water between soft water and hard water is regarded as middle hard water.
¡¡Most water in Japan is soft water which has less than 100 mg hardness in 1 liter. Hardness is one of important factors for water taste. Generally, it is said that hard water has firm taste. By cooling in refrigerator, crystal taste becomes stronger as well as change to better taste. On the other hand, soft water spread in the mouth gently. Soft water is suitable for Japanese tea or tea which is more important of the smell and taste.
¡¡Now, shop mineral water contents are indicated as follow. Because People, such as Japanese, usually drink soft water which contains less minerals, it is said that they don't feel good taste in other countries mineral waters which contains lots of minerals. However, mineral water in France is very popular because it seems that they feel good taste. Thus, it seems that hardness is not only the factor for good taste water.
Water hardness = calcium mg/l ¡ß2.5+ Magnesium mg/l¡ß4.1¡áHardness mg/l

¡¡According to "good taste water research conference" conducted in 1985 by Health, Labour and Welfare Ministry in Japan, these are items for good taste water.

¡¦Residue on evaporation (Minerals)¡§30¡Á200mg/l
¡¦Hardness¡§10¡Á100mg/l
¡¦Free carbon dioxide¡§3¡Á30mg/£ì
¡¦Consumption of potassium permanganate¡§Less than 3 mg/l
¡¦Odor strength: Less than 3
¡¦Residual chlorine¡§Less than 0.4 mg/l
¡¦Water temperature¡§Highest 20 ¡î (better 10 to 15¡î)

¡¡The effects of these items are following.

¡¡¡¦Residue on evaporation

It is the amount of minerals such as Natrium, Calcium, Magnesium, Kalium, Iron, and Manganese. It will be a mild taste if the balance of minerals is good. If too much minerals, the taste becomes hard or bitter.

¡¡¡¦Hardness contents

The main contents of minerals are Calcium and Magnesium. If the water is lack of them, the taste becomes not mild.

¡¡¡¦Free carbon dioxide

It is carbon dioxide dissolved in water. When water contains carbon dioxide, the water is like fizzwater. If it is too much, it becomes too stimulus.

¡¡¡¦Consumption of potassium permanganate

The level of organic matters in water. If it is too much, the water has mold odor or hard taste.

¡¡¡¦Odor strength

It is indicated by dilution rate when targeted water becomes no smell by additing non-odor water. Mold odor is especially regarded as issue.

¡¡¡¦Residual chlorine

The residual amount of chlorine after sterilization. In water supply law in Japan, tap water should contain 0.1 mg/L chlorine.
If the amount is too much, it smells like chlorine so that the water has bad taste.

¡¡¡¦Water temperature

Water temperature is the important factor for good taste water. People feels pleasant cooling sensation by water with 10 to 15¡î.

¡¡There is other new index for good taste water recently. It is "O-index."
This index reports that water which has less Magnesium (Mg) and sulfate ion (SO4) while more Calcium (Ca)and Kalium (K) is good taste. 80% of Water in Japan is classified it as more than 2.0.
¡¡Water taste depends on especially water temperature. Even bad taste tap water, by removing chlorine odor and cooling 10 to 15 ¡î in refrigerator, it becomes better taste which is similar to mineral water.
¡¡In Tokyo, Japan, bottled water from tap water purified by advanced treatment are sold as "Tokyo water."
Let's compare mineral waters.