Sweet or tart, wine is a delicious drink made by fermenting grapes that come in different flavors and colors. The acidity of wine is an important factor in determining its unique taste and texture. This is what makes pH the second most important factor of winemaking. The first is the sugar content.

pH is an essential parameter in winemaking as it correlates to the acid content present during the fermentation process, contributing to the flavor and shelf life of the product. Most wine manufacturers keep the pH value of their wine within 3.0 to 4.0 units. The desired quality and batch consistency depends on this pre-defined value.

Maintaining the pH level within a specific range is crucial for its stability and longevity. If the pH level is high, it can lead to oxidation, bacterial growth and fermentation, thereby adversely affecting the taste, aroma and overall quality of the wine.

The measuring pH of the wine, however, can be a little tricky. Wine contains various organic acids, including tartaric, malic and citric, which can interfere with the pH measurement. The presence of alcohol in wine can also affect the pH measurement. Besides, the grape particles often clog the pH sensors. This is particularly challenging during the initial fermentation stage when frequent measurements are needed.

Some of the other challenges in the pH measurement of wine are as follows:

  • The samples need to be prepared accurately for consistent pH levels throughout the wine and free of air bubbles.
  • The pH values may vary due to temperature variations.
  • The need for specialized measurement equipment and difficulty in selecting appropriate sensors and buffers.

The table below outlines the challenges and negative effects on pH measurement results when using a typical sensor for wine samples.

There are various ways to overcome these challenges, starting from choosing the right meter, sensor, buffers and solutions for the measurements to preparing the wine samples accurately. Download METTLER TOLEDO’s application note on how to measure the pH level in wine precisely. It also provides a step-by-step guide on how to select the right system for these measurements.

Discover the ideal pH measurement system for your specific needs here.

So, red or white, remember the significance of pH in the glass of your wine!

To contact the author of this article, email pHmatters@mt.com