Application Method

pH Measurement of Soft Drinks

Application Method

How to Measure pH in Soft Drinks Accurately: Tips for Sensor Selection

pH of soft drinks
pH of soft drinks

Whether you like the refreshing tang of citrus soda or the subtle sweetness of cola, the right pH level brings out the best flavor. The pH of most carbonated drinks, which are approximately 94% water, typically ranges between 2.5 and 3.5. A slight deviation from this range can lead to off-flavors and impact product stability.

However, measuring pH in soft drinks can be challenging due to their unique properties, including carbonation and varying viscosity. You need a sensor that responds quickly and accurately to fluctuations to ensure precise and reliable measurements.

The InLab® Versatile Pro is a cost-effective pH sensor with a replaceable ceramic junction, tailor-made for carbonated beverage production. This sensor is ideal for routine pH measurements, delivering rapid and accurate results with minimal user effort. Its body is made of polysulfone for robustness, making it well-suited for both laboratory and at-line applications in challenging production environments.

Download our application note for more information on measuring pH in soft drinks and about this sensor.

The following section provides more insights into soft drink samples, their composition, and why accurate pH levels matter.

What are soft drinks?

Soft drinks, the most prominent category in the non-alcoholic beverage sector, are made from water and sugar. Originally derived from mineral-rich spring water, they are now usually carbonated by bubbling in carbon dioxide (CO2) gas for added fizz. Their manufacturing process is similar to other popular beverages such as energy drinks and iced tea. To accommodate the border range of products, the trade association for US beverage producers, formerly the National Soft Drink Association, has changed its name to the American Beverage Association.

Why is pH measurement important in soft drinks?

The pH of a soft drink is important for its flavor, aroma, and safety. Soft drink manufacturers must adhere to stringent guidelines set by regulatory agencies to ensure the consistency and quality of their products. pH measurements at different stages of soft drink manufacturing help ensure the drinks meet regulatory standards. The concentration of CO2, which imparts the fizz, is also one of the key factors affecting pH. As the sweetness and tartness of these beverages determine their overall flavor, pH consistency is critically important to brand loyalty.

How are soft drinks carbonated, and what is their pH range?

Carbonation occurs when pressurized CO2 is passed through water, producing carbonic acid and dissolved CO2 gas. Most carbonated drinks, which are approximately 94% water, have a pH of around 2.5 to 3.5 and are hence highly acidic. However, the partial pressure of CO2 has an important relationship with pH. The typical soft drink is carbonated at 2.5 atmospheric units (atm), resulting in a high concentration of dissolved CO2 and an acidic medium of pH 3.7. Dissolved CO2 is low at normal atmospheric conditions, and the pH of soft drinks is now closer to neutral (around 5.7). The amount of carbon dioxide pressure also depends on the type of soft drink.

How often should pH levels be tested in soft drinks during production?

pH levels should be tested at critical points in the production process, typically at least once per batch. However, depending on the production volume and the product's sensitivity, more frequent testing may be necessary.

How does temperature affect pH measurements in soft drinks?

Temperature can significantly affect pH readings; thus, measuring pH at a consistent temperature or using a pH meter with automatic temperature compensation (ATC) to ensure accurate results is important. METTLER TOLEDO's InLab® Versatile Pro pH sensor has a replaceable ceramic junction and integrated temperature probe.

What are the common challenges in measuring pH in soft drinks?

Reading fluctuations, sluggish sensor response due to clogged reference junctions, and varying measurement environments are key challenges in measuring pH in soft drinks. Temperature variations require integrated temperature probes for accurate compensation, while regular calibration and maintenance are essential to ensure sensor accuracy.

For further details, download our application note.