Proper skin pH is essential for a healthy complexion. The pH of one's stomach directly affects the digestive process. The pH of the soil regulates the availability of nutrients for plant growth, as well as the activity of soil bacteria. The efficient production of food products depends upon careful pH control. The proper curd size, uniformity, and structure of cottage cheese are directly related to the pH at cutting time.
Yeast can ferment and leaven dough only within certain pH limits.
Jelly will not gel properly unless the pH is in the 3.5 region. Accurate pH measurement is necessary to the study of many chemical processes. The researcher needs to know the pH at which a chemical reaction proceeds at its fastest in order. The engineer uses the information to develop practical commercial processes. The pH of a river or lake is important in maintaining a proper ecological balance.