Understanding Purified Water
Purified water, like Walmart's Great Value brand, undergoes a rigorous process to remove impurities, contaminants, and dissolved solids. This contrasts with spring water, which comes from an underground source and is filtered naturally, retaining its mineral content. The most common method for creating purified water is reverse osmosis, a technology that forces water through a semipermeable membrane. While this makes the water exceptionally clean, it also strips it of minerals like calcium, magnesium, and bicarbonates.
The Side Effect of Purity: Flat Taste
One major consequence of ultra-purification is a lack of flavor. Water isn't purely tasteless; its taste profile is influenced by the minerals it contains. By removing almost all Total Dissolved Solids (TDS), the final product can taste lifeless or 'flat' to consumers accustomed to the flavor of natural spring or tap water. To address this, bottled water companies intentionally add a blend of minerals back into the water, a process known as remineralization.
The Role of Sodium Bicarbonate
Sodium bicarbonate, commonly known as baking soda, is a mild alkaline substance and a key component in this remineralization process. Here’s what it does:
- Enhances Flavor: By reintroducing minerals like sodium bicarbonate and calcium chloride, bottlers can create a more palatable and familiar taste profile for purified water. This makes the product more appealing to a wider range of consumers.
- Balances pH: Purified water can sometimes become slightly acidic during treatment. Sodium bicarbonate acts as a buffering agent, increasing the water's alkalinity to a more neutral or slightly alkaline pH. A balanced pH can contribute to a smoother, cleaner mouthfeel.
- Corrosion Control: In the water treatment industry, adding bicarbonates is a common practice for corrosion control. It helps protect the internal surfaces of pipes and storage containers by stabilizing the water's chemistry. This is an important consideration for maintaining product quality and equipment longevity.
Why it’s Safe in Small Amounts
The concentration of sodium bicarbonate in bottled water is minimal and considered safe for consumption. The purpose is to achieve the desired taste and pH, not to deliver a high dose of sodium. For context, the sodium content in a standard bottle is far below the amount found in many common foods and beverages. However, individuals with health conditions such as high blood pressure or kidney disease should be mindful of their overall sodium intake.
Comparison of Water Types
| Feature | Purified Water (with minerals) | Spring Water | Tap Water (Municipal) |
|---|---|---|---|
| Source | Municipal or ground water | Naturally occurring underground source | Public water supply system |
| Purification | Extensively filtered (e.g., reverse osmosis, distillation) | Natural filtration through rock layers | Coagulation, flocculation, filtration, disinfection |
| Taste Profile | Neutral or slightly mineralized taste from additives | Flavor profile varies based on mineral content of the source | Taste depends on local mineral composition and treatment |
| Mineral Content | Minerals added back intentionally (e.g., sodium bicarbonate, calcium chloride) | Contains naturally dissolved minerals | Varies widely by municipality; often contains minerals |
| Purity | High purity due to extensive filtration | Purity can vary based on source | Quality regulated by local and national standards |
Conclusion
Walmart's decision to include sodium bicarbonate in its Great Value purified water is a standard industry practice driven by consumer preference and water chemistry. The purification process creates water so pure that it lacks flavor, so small amounts of minerals are added back to create a pleasant and balanced taste. This process also ensures the water has a stable pH level. Consumers can rest assured that the practice is safe and simply part of what makes bottled purified water taste good, rather than an unnecessary chemical addition.
Frequently Asked Questions
1. Is sodium bicarbonate in bottled water harmful? No, the small amount of sodium bicarbonate added to bottled water for taste and pH balance is not harmful. It is a common, food-safe additive.
2. Why does pure water need minerals added back? Pure water, such as that produced by reverse osmosis, has a flat or dull taste due to the absence of minerals. Remineralization with compounds like sodium bicarbonate restores a more appealing and familiar flavor.
3. How is sodium bicarbonate different from regular salt? While both contain sodium, sodium bicarbonate (baking soda) is a different chemical compound from table salt (sodium chloride). In water, it primarily affects pH rather than taste in the same way that salt does.
4. Does the added sodium affect my health? The amount of sodium added to purified water is very small. For most healthy individuals, it will not have a significant impact. People on low-sodium diets should always check nutrition labels.
5. Can adding sodium bicarbonate to water make it alkaline water? Yes, sodium bicarbonate increases the alkalinity of water. While it makes the water slightly more basic, it is a different process than the ionization used for some dedicated alkaline water products.
6. Do all bottled water brands add sodium bicarbonate? No, not all brands add it. Spring water, for example, retains its natural minerals. Brands that sell purified water are more likely to add minerals back for taste.
7. What is the pH of Walmart's water after adding sodium bicarbonate? Research and testing show that Walmart's Great Value purified water with added minerals has a slightly alkaline pH, which is desirable for a smoother taste. The specific pH can vary slightly.
8. Why is Walmart water so cheap if it's purified? Walmart's Great Value water is purified from a municipal or ground source, which is generally more cost-effective than sourcing natural spring water. The efficiency of the purification and bottling process allows them to offer it at a lower price point.
