Drinking water should be relatively germ-free, appetizing and inviting according to DIN 2000:2000-10. It should be colorless, cool, odorless and exhibit a flawless flavor.
For evaluating a water sample, e.g., at the source of a water supply, sensory analysis should detect any off-aromas, such as earthy, peaty, musty, mildewy, manure-like, fishy, stagnant, fecal and chemical odors. A chemical odor could arise from hydrogen sulfide, chlorine, mineral oil, ammonia, phenol, chlorophenol, xylenol or tar. In surface water, odors originating from plankton blooms can develop, which are reminiscent of soil (blue-green algae), fish (diatoms), cucumbers or seaweed (flagellates).
If there is no danger of infection, an evaluation of the aroma and mouthfeel of the water is performed to discern the following attributes in greater detail, which are characterized as “weak” or “strong”, if they are at all apparent:
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bland (soft water)
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salty (high sodium chloride content)
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bitter (high magnesium content)
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alkaline (high pH)
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sour (low pH)
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astringent, ink-like (high iron and aluminum content)
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metallic (high lead, copper or zinc content, especially as an aftertaste)
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rotten (contamination)
If the samples for testing the aroma are not evaluated on-site but rather in a laboratory, a water sample (100–150 ml) should be collected in an Erlenmeyer flask (total volume: 200–300 ml) and closed with a glass stopper. Subsequently, immediately prior to performing the evaluation, the water sample is heated to 40–60 °C and shaken thoroughly. For the taste test, the sample is heated to 30–40 °C before performing the test.
According to how water is obtained, its contents and potential pharmacological effect, the product group, which comprises water designated for human consumption, can be further divided into the subcategories of mineral water, table water (drinking water) and therapeutic water as stipulated by the "Verordnung über natürliches Mineralwasser, Quellwasser und Tafelwasser" (regulations governing natural mineral water, spring water and bottled drinking water).
Moreover, a rapidly growing market segment has become established in the last 20 years with a substantial number of products successfully launched, which have successfully closed the gap between water and two beverage categories containing fruit: fruit nectars and fruit juice/mineral water beverages. This so-called “flavored water” (often referred to as “near water” or “aqua plus”) comprises products created with water, enhanced by adding flavor notes based on fruit aromas or extracts. Depending on how the product is to be positioned on the market (e.g., as a “natural” product, soft drink, health or sport drink), supplementing the beverage with functional ingredients, such as minerals, vitamins or oxygen, is also possible.
References
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DIN 2000:2000-10, Zentrale Trinkwasserversorgung – Leitsätze für Anforderungen an Trinkwasser, Planung, Bau, Betrieb und Instandhaltung der Versorgungsanlagen – Technische Regel des DVGW, Beuth Verlag, Berlin
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K. Höll, Wasser: Untersuchung, Beurteilung, Aufbereitung, Chemie, Bakteriologie, Virologie, Biologie, 7. Auflage, Walter De Gruyter, Berlin, 1986
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