The Pure and Unusual Flavor Profile
Demineralized water, also known as deionized water, undergoes intensive processes like reverse osmosis or ion exchange to remove almost all of its mineral content, specifically salts and other ionic impurities. The taste of regular drinking water comes from these very minerals, which are naturally absorbed as water travels through rock and soil. When these are removed, the water's taste becomes noticeably different.
Experts and those who have tasted it often describe the flavor of demineralized water as "flat," "bland," or "insipid". Instead of tasting nothing, our taste receptors react to the absence of the minerals they are accustomed to detecting. Since there are no dissolved solids like calcium, magnesium, or potassium to provide a flavor profile, the water may simply taste like nothing at all to some, while others perceive a strange or even unpleasant aftertaste. This phenomenon is particularly noticeable when comparing it directly to mineral-rich tap or spring water.
The Science Behind the 'Tasteless' Taste
Our perception of taste is a complex interaction involving our tongue's receptors, our sense of smell, and the brain's interpretation of these signals. In the case of pure water, the brain is missing the usual mineral markers it expects, which can result in the sensation of 'flatness.' This is an example of how the absence of a flavor can, in itself, be a recognizable sensory experience. Essentially, what we are tasting is the absence of taste. Volatile organic compounds and dissolved gases, like carbon dioxide, can still be present in some forms of demineralized water, which could slightly alter the flavor. However, the most significant factor is the near-total removal of charged mineral ions.
Demineralized Water vs. Tap Water
Tap water, by contrast, contains a variety of dissolved minerals and salts, the specific composition of which is dependent on the local geology and water source. This is why tap water from one city can taste completely different from another. These minerals, including calcium, magnesium, and sodium, are what give tap water its characteristic flavor, which people have grown accustomed to. The purification process for municipal tap water also typically involves disinfection with chlorine, which can leave a distinct smell and taste that many find unpleasant, but is still a recognized flavor profile.
Common tastes in tap water include:
- Chalky or smooth: High levels of calcium and magnesium, which define hard water.
- Salty: Higher concentrations of sodium chloride.
- Metallic: Elevated levels of iron or copper from plumbing.
- Chlorine: The taste and smell of the disinfectant added for safety.
Because demineralized water lacks these minerals, it does not carry the regional flavors of tap water. This is why for applications requiring absolute purity, like in laboratories or with medical equipment, demineralized or distilled water is used to prevent mineral buildup and contamination.
Comparison Table: Demineralized Water vs. Distilled Water
While often used interchangeably in discussion, there are important distinctions between demineralized and distilled water.
| Feature | Demineralized (Deionized) Water | Distilled Water |
|---|---|---|
| Production Method | Ion exchange resins, reverse osmosis. | Boiling, evaporation, and condensation. |
| Impurities Removed | Primarily mineral ions, but may retain bacteria, viruses, and uncharged organic compounds. | Minerals, bacteria, viruses, most organic and inorganic substances. |
| Final Purity | Very low electrical conductivity, but not always microbiologically pure. | Considered higher purity; removes a broader range of impurities. |
| Taste | Flat, bland, or off due to lack of minerals. | Often described as flat or bland, with no mineral flavor. |
| Primary Use | Industrial applications, lab use, equipment cooling. | Medical equipment (autoclaves), lab use, engine cooling. |
Is Demineralized Water Safe to Drink?
While safe to drink in small quantities, demineralized water is not recommended for regular consumption, particularly over the long term. The World Health Organization (WHO) and other health authorities have raised concerns about potential adverse health effects. The reason is twofold:
- Leaching of Minerals: Because it lacks minerals, demineralized water can be aggressive, potentially leaching metals from plumbing and storage containers. Additionally, it can draw minerals from the body during digestion.
- Lack of Essential Minerals: The water we drink contributes to our daily intake of essential minerals like calcium and magnesium. While food is the primary source, water can play a supplementary role. Without these minerals, prolonged consumption could contribute to deficiencies. For example, studies have linked the long-term consumption of low-mineral water to increased risks of certain cardiovascular diseases.
For those seeking purified drinking water, many modern reverse osmosis systems now include a remineralization stage, which adds a healthy and palatable balance of minerals back into the water. This creates a clean-tasting and nutritionally-enhanced product that is far more enjoyable for daily consumption.
Conclusion
In summary, the taste of demineralized water is best described as flat, bland, or neutral because it lacks the minerals and dissolved solids that give most water its characteristic flavor. While pure and useful for specific industrial or laboratory applications, it is generally considered unpleasant for drinking. For daily hydration, most people prefer water with some mineral content, whether from tap, natural springs, or remineralized filtered systems. The flavor we associate with 'good' water is actually the result of natural impurities, proving that in this case, pure isn't necessarily better for your palate or your long-term health.
Optional Outbound Link: For further reading on the relationship between water hardness and health, see this study on health risks from drinking demineralised water from the World Health Organization.
