The Meaning of pH
The term “pH” is commonly used in processing foods. What does it mean?
It is simply the symbol of a scale, numbered from 0 to 14, that rates water solutions according to their acidity or alkalinity.
Pure water is given the number 7 - right in the middle of the scale - because it contains an equal number of acidic and basic ions and is therefore neutral. As the alkalinity of a solution increases, the pH value goes up; as the acidity increases, the pH goes down. Each step represents an increase or decrease by a factor of ten.
On this scale, the most acid substance is hydrochloric acid, which , in proper concentration, is rated at 0, or ten million times as acid as water. At the other end of the scale is a solution of sodium hydroxide, rated at 14, or 10 million times as alkaline as water. Solutions of other substances take their places in between.