In wine grapes, potassium plays an important role in determining the pH of juice and the stability of finished wine. As the potassium content in grapes increases, tartaric acid binds with potassium ions, forming potassium tartrate. Once saturated, potassium tartrate will precipitate, removing free acidity from juice. This results in a juice with decreased acidity and increased pH. Potassium uptake from the soil by the grapevine roots is accelerated in warm, dry climates. This causes the resulting grapes to typically have pH values above the ideal range of pH 3.0 to 3.8.
Wines and juice with pH values above pH 3.8 due to high potassium content may be adjusted by the addition of tartaric or malic acid. These adjustments will both lower the pH and raise the acidity, and are typically made in the juice before fermentation. Potassium can also naturally be lowered in grapes by limiting the availability of potassium to the vines or utilizing a blend of wine grapes to ensure an ideal balance of potassium, pH, and acidity.
Winemakers with a robust laboratory setting may use ion selective electrodes (ISEs) to understand the potassium concentration of their juice, must, or wine.
A selection of portable and benchtop ISE meters are available to measure potassium in wine using a potassium ion selective electrode.
Below are the most common conductivity products for measuring potassium during the wine making process.
For the Winemaker we offer the HI5000 series benchtop meters These meters are our most advanced meters incorporating the latest microprocessor to bring exceptional features and performance for the most demanding user. These meters are completely customizable to user specific requirements. The meters have an Ion Selective Electrode (ISE) input and are pre-programmed with the molecular weight and ion charge for potassium so that measurements can be displayed in various forms of concentration units.
A portable ISE meter is available to measure potassium. The portable meter is convenient in that it does not take up much benchtop space and can be stored in the carrying case when not used. The portable meter, like the benchtop meters, requires a stirrer for mixing the sample when performing the measurment.
Ion Selective Electrodes
Potassium ISEs in this category include both combination and half cell versions. A reference half-cell electrode for use with the potassium half-cell can also be found in this category.
In this category are the calibration standards and ISA solutions used to calibrate the meters and perform potassium concentration measurements.
Accessories in this category include magnetic stirrers for adequate mixing along with replace parts for the potassium ISE.