What does the 'expiration date' on bottled water mean?
Many consumers are confused by the expiration date printed on bottled water, assuming it means the water itself goes bad. In reality, the U.S. Food and Drug Administration (FDA) does not require bottled water to have an expiration date, and manufacturers primarily use it for quality and inventory control purposes. The critical factor is the packaging material, usually plastic, which deteriorates over time and under specific conditions. When stored improperly, especially in heat or direct sunlight, the plastic can break down and leach chemicals into the water, which can affect the taste and, more importantly, pose health risks.
The risks of drinking water from an old plastic bottle
Even if the water is perfectly pure, the container itself can introduce contaminants. This risk is present with any bottled water, not just alkaline. The primary risks are linked to plastic degradation, not microbial growth within a sealed bottle. Heat and sunlight are major catalysts for this process. The chemicals commonly leached from plastic, such as antimony and bisphenol A (BPA), have been linked to potential health issues including hormonal disruptions and increased cancer risk with long-term exposure. Therefore, the expiration date serves as a manufacturer's guideline for when the water's taste and the bottle's integrity are guaranteed to be at their best.
How plastic leaching affects alkaline water
Alkaline water, which has a higher pH level, is particularly susceptible to changes influenced by its environment. The beneficial properties of alkaline water, including its antioxidant potential and high pH, are not stable indefinitely. Over time, particularly when the container's integrity is compromised, the water's pH can drift back towards neutral due to exposure to carbon dioxide from the air. This not only negates the purpose of buying alkaline water but can also exacerbate the effects of plastic leaching. For instance, the mineral hydroxides that contribute to the water's alkalinity can be edged out by CO2, leading to a breakdown of the water's special properties.
What happens to alkaline water's properties over time?
Alkaline water, especially ionized water, is best consumed fresh. The two most sought-after properties, high pH and antioxidant potential, are transient. The negative electrical charge, or oxidation-reduction potential (ORP), which gives the water its antioxidant properties, is the most fragile and can dissipate within 24 to 48 hours of being made. The higher pH level, though more stable, will also gradually decrease as the water is exposed to air, causing it to absorb carbon dioxide and become more acidic.
Proper storage preserves quality
To maintain alkaline water's quality and delay the effects of degradation, proper storage is paramount. Here are some key recommendations:
- Use airtight containers: Storing alkaline water in a container with a tight seal helps minimize exposure to air and prevent the absorption of carbon dioxide, thus preserving its pH.
- Opt for non-reactive materials: Glass is the best choice for storing water long-term because it is non-reactive and does not leach chemicals. Alternatively, BPA-free plastic or vacuum-sealed stainless steel bottles can be used.
- Refrigerate: Storing alkaline water in the refrigerator helps to slow down both bacterial growth and the loss of its alkaline properties.
- Avoid sunlight and heat: Direct sunlight and high temperatures dramatically accelerate the breakdown of plastic and can promote bacterial or algae growth, even in sealed containers.
- Consume promptly: Once a bottle is opened, its exposure to air and potential contaminants increases significantly. It's best to consume it within 24 to 48 hours to enjoy its full benefits and quality.
Potential health risks of expired alkaline water
Although the risk may be low for a single consumption, the accumulation of leached chemicals from old or improperly stored plastic bottles is a genuine concern. Long-term consumption of water contaminated with chemicals like BPA and phthalates can potentially lead to hormonal disruptions, liver problems, and a weakened immune system. While the water itself does not spoil in the traditional sense, the degraded packaging makes it a questionable choice. Moreover, expired alkaline water will have lost its intended pH benefits, rendering it no different than regular water, but with the added risk of chemical exposure from the packaging.
Comparison: Expired vs. Fresh Alkaline Water
| Feature | Expired Alkaline Water (Past Expiration) | Fresh Alkaline Water (Before Expiration) |
|---|---|---|
| Alkalinity (pH) | Significantly reduced, likely near neutral due to CO2 absorption. | At or near the advertised high pH level (e.g., pH 8-10). |
| Antioxidant Properties | Lost, as the negative ORP dissipates quickly, often within 48 hours. | High initial antioxidant potential, especially in ionized water. |
| Chemical Leaching | Higher risk, especially if exposed to heat or sunlight. | Minimal risk, assuming proper storage and bottle integrity. |
| Taste | May develop an off, metallic, or plastic-like flavor. | Clean, smooth taste with no foreign flavors. |
| Overall Safety | Caution advised; depends heavily on storage conditions. | Generally considered safe when purchased and stored properly. |
Conclusion
In conclusion, while the water molecule itself is stable, the safety and quality of expired alkaline water are compromised by the deterioration of its plastic bottle and the degradation of its special properties. The expiration date on the bottle serves as a warning for the packaging, not the water itself. For maximum benefits and safety, it is best to drink alkaline water within a reasonable timeframe after purchase, store it correctly in a cool, dark place, and use a non-reactive container like glass or BPA-free plastic. The small, transient benefit of alkaline water is not worth the potential long-term risks associated with chemical leaching from old, degrading plastic. When in doubt, it is always safest to discard any bottled water that is significantly past its expiration date or has been stored improperly.
For more detailed information on bottled water safety and quality, you can consult resources from the International Bottled Water Association (IBWA).
Is it safe to drink expired alkaline water?: Quick Guide
Expiration date is for the bottle: The date on bottled alkaline water applies to the plastic container, not the water itself. Plastic leaching is the primary risk: Over time, and especially when exposed to heat, plastic bottles can leach harmful chemicals like BPA and antimony into the water. Alkalinity diminishes quickly: The high pH and antioxidant potential of alkaline water are not stable and decrease significantly after opening, making expired water less effective. Proper storage is key: To preserve quality, store alkaline water in a cool, dark place and preferably in a glass or BPA-free container. Taste and odor can indicate contamination: If expired water has a strange odor, metallic taste, or visual changes, discard it immediately. Fresh is best for benefits: To get the full intended effects of alkaline water, consume it fresh and well before its listed best-by date.
FAQs
Q: Does water itself expire? A: No, pure water is a stable compound and does not expire, but the container it is stored in, particularly plastic, can degrade over time and affect the water's safety and taste.
Q: What are the potential health risks of drinking expired bottled water? A: The main risk comes from chemicals leaching from the plastic bottle, which can potentially cause hormonal disruptions, weaken the immune system, and in rare cases, lead to other health complications.
Q: What happens to the pH of expired alkaline water? A: The pH of alkaline water will gradually decrease over time as it is exposed to air, which allows it to absorb carbon dioxide and become more acidic, reducing its alkalizing effect.
Q: Can I still drink expired alkaline water if it was never opened? A: If stored properly in a cool, dark place, unopened bottled water can remain safe past its expiration date. However, its taste and quality may be diminished, and the risk of plastic leaching still increases over time.
Q: How can I tell if expired bottled water has gone bad? A: Look for any changes in appearance (such as froth or discoloration), smell, or taste. If the water smells strange, tastes metallic or plastic-like, or has a different appearance, it is best to discard it.
Q: What is the best way to store alkaline water to make it last longer? A: The best way is to store it in a tightly sealed, non-reactive container like glass, in a cool, dark place, and away from any strong odors.
Q: How long can I keep alkaline water after opening it? A: Once opened, it is recommended to consume alkaline water within 24 to 48 hours to preserve its optimal alkalinity and taste, as exposure to air will cause its properties to diminish quickly.
