What is pH?
pH is the measurement of the concentration of free hydrogen ions in a liquid. The pH of pure water is 7. Liquids with a larger concentration of hydrogen ions than water are acid and have a pH value less than 7. Liquids with a lower concentration of hydrogen ions on the other hand, are base and have a pH value higher than 7. The pH scale runs from 1 to 14.
Can I measure the pH instead of the acidity of the must?
No! In winemaking, the acidity is the representation of the amount of grams of acid in your wine/juice, usually expressed in grams of tartaric acid per litre. This can only be measured with a special indicating solution like Vinoferm® blue indicator. You can, however, use a pH meter in combination with the blue indicator: instead of adding blue indicator until the colour turns blue, add blue indicator until a pH of 7.00 is obtained. This method is more accurate and gives better readings for, amongst other things, red juices! The combination pH meter, blue indicator and an automatic burette is a professional set-up for accurately measuring acidity.
The maintenance of a pH meter
The pH meter is a precision instrument. Proper use and appropriate maintenance are important to enjoy your pH meter for a long time. Here are some considerations:
- When you purchase the electrode, it is usually dehydrated. First, you let it soak for 4 hours in the storage solution. After each use the cap that slides over the electrode also has to be filled with this storage solution. This keeps your electrode functioning properly much longer.
- Before the first measurement, the pH meter needs to be calibrated with the buffer solutions. If the pH meter can only be calibrated at one point, use the buffer solution that is closest to your normal measurements.
- When calibrating be careful that no contamination of the buffer solution occurs. Therefore never insert the electrode directly into the bottle, but instead measure by pouring a small amount in a separate cup. After calibration throw away the used cups, do not pour the liquid back into the bottle!
- Preferably never touch the electrode, certainly not with your fingers. If you would like to clean it, only use a soft cloth without rubbing the electrode.