pH is a fundamental element of the wine-making industry. pH strongly influences wine properties such as color, oxidation, biological and chemical stability. The IQ benchtop and handheld ISFET meters are accurate and reliable tools for measuring wine pH.
pH measures the quantity of acids present, the strength of the acids, and the effects of minerals and other ingredients in the wine. Wine pH depends on three main factors: the total amount of acid present, the ratio of malic acid to tartaric acid, and the amount of potassium present. Wines that contain little acid and excess potassium show high pH values. Wine with more tartaric acid, less malic acid, less potassium and more titratable acid has lower pH values.
pH values range from 2.9 to 4.2 in wine. Wine’s chemical and biological stability are very dependent on pH value. Lower pH values are known to improve the stability, so winemakers usually prefer a pH range of 3.0 to 3.5. The wine is so stable in this range that many winemakers believe pH is a crucial guideline in wine making.
There are many advantages to low pH values in wine. Low pH inhibits bacteria, causes sugar fermentation to progress more evenly and makes malolactic fermentation easier to control. Low pH also has a direct influence on the hot stability of wine. When bottled wines are stored in warm areas, protein precipitates out of them, causing serious problems. These wines are then treated with bentonite, which removes excess protein. pH is important to the treatment because bentonite successfully removes more protein when the pH value is low. If wine pH increases, bentonite is less effective, making it necessary to add larger amounts. The danger is adding too much bentonite because it can strip wines of their unique aromas and flavors.
An example of the importance of low pH is displayed with Sauvignon Blanc. Sauvignon Blanc grapes normally have large amounts of protein, so they can be difficult to sufficiently stabilize when pH values are too high.
Low wine pH results in better visual qualities as well. When pH is lower, both red and white wines maintain better color intensity. Red wines have more and better color and white wines do not brown as easily.
When wine has high pH values, bacteria grow rapidly and undesirable bacterial fermentation is more problematic. This condition causes less biological and chemical stability, and poorer color. Wines with a high pH always need more attention and greater care.
Refer to the table below as to the effects of pH levels on wine quality:
| Wine Characteristic | Low pH Range (3.0-3.4) | High pH Range (3.6-4.0) |
| Oxidation | Less | More |
| Amount of color | More | Less |
| Kind of color | Ruby | Browner |
| Yeast Fermentation | Unaffected | Unaffected |
| Protein Stability | More stable | Less Stable |
| Bacterial Growth |
Less | More |
| Bacterial Fermentation | Less | More |
As you can see, pH measurement is very important to the process of wine making. In order to ensure the best quality, use IQ benchtop and handheld ISFET meters with stainless steel probes. Conventional probes have glass bulb sensors, which are easily clogged by the chemical ingredients of wine. Clogging causes unstable and incorrect pH readings. The IQ silicon chip sensor eliminates this problem. Our probes have no glass to break and maintain high accuracy and fast response times. The sensors are easy to clean with a toothbrush and detergent. Don’t waste your time maintaining delicate sensors. IQ guarantees rugged and reliable pH measuring equipment to improve your wine quality. One probe also features a piercing tip for measuring at the grape level of processing.