Alkaline water has a pH level greater than 7.0, typically ranging from 8 to 9.5. This contrasts with neutral water, which has a pH of 7, and acidic water, which has a pH below 7. The elevated pH in alkaline water is attributed to the presence of dissolved alkaline minerals, such as calcium, magnesium, and potassium. These minerals contribute to the water’s capacity to resist changes in pH, providing a buffering effect.
What Affects Water Alkalinity
Alkaline water can gradually lose its elevated pH due to several environmental interactions. A primary factor is the absorption of carbon dioxide (CO2) from the surrounding air. When CO2 dissolves into water, it reacts to form carbonic acid, which introduces hydrogen ions and lowers the water’s pH, moving it towards a more neutral or acidic state.
Another factor influencing alkalinity is the precipitation of dissolved minerals. Alkaline water often contains minerals like calcium and magnesium, which contribute to its buffering capacity. Over time, particularly when exposed to heat or light, these dissolved minerals can precipitate out of the solution, forming solids. This reduction in dissolved alkaline compounds diminishes the water’s ability to maintain its higher pH.
Temperature also plays a role in the stability of alkaline water. Higher temperatures can accelerate the rate at which CO2 dissolves into the water, thereby hastening the formation of carbonic acid. Additionally, warmer conditions can increase the rate of mineral precipitation, further contributing to a decrease in alkalinity.
How to Maintain Alkalinity
To preserve the higher pH of alkaline water, specific storage practices are beneficial. Storing alkaline water in airtight containers is highly recommended to limit its exposure to atmospheric carbon dioxide. A tightly sealed container minimizes the opportunity for CO2 to dissolve into the water and form carbonic acid, which would otherwise lower the pH. Filling the container to the brim can further reduce the air space available for CO2 interaction.
The choice of container material also impacts alkalinity retention. Glass containers are generally preferred because they are inert and do not react with the water or leach chemicals that could alter its pH. Food-grade stainless steel is another suitable option for similar reasons. While some plastics are used, choosing BPA-free varieties is advisable to minimize potential chemical interactions.
Storing alkaline water in a cool, dark place helps mitigate factors that lead to pH reduction. Cooler temperatures slow down the chemical reactions involved in CO2 absorption and reduce the likelihood of mineral precipitation. Keeping the water away from direct sunlight also helps prevent temperature increases and light-induced chemical changes that could degrade alkalinity. Refrigeration can further stabilize the water’s temperature and prolong its elevated pH.
Assessing Alkalinity Over Time
The duration alkaline water maintains its pH varies significantly based on storage conditions. If left in an open glass, alkaline water may retain its optimal properties for only about two hours due to constant air exposure. When stored in a sealed, opaque bottle with some air, alkalinity can last for approximately two days. For the longest retention, an airtight, opaque container filled to minimize air space can help maintain alkalinity for up to two weeks.
Over time, a noticeable change in the water’s taste can indicate a loss of alkalinity, often becoming more neutral or slightly acidic. Visual cues are generally unreliable as there are often no apparent changes, although sometimes mineral precipitation might be observed as sediment. The most accurate way to assess alkalinity is through pH testing. Simple and accessible tools for this include pH test strips or digital pH meters.
To use pH test strips, a strip is dipped into a water sample for a few seconds, and its resulting color is then compared to a color chart provided with the kit to determine the pH level. Digital pH meters offer a more precise numerical reading; these devices typically involve immersing an electrode into the water and waiting for a stable value to display. If the pH level has dropped significantly, the water has lost its intended properties and reverts to a more neutral state.