A buffer zone in chemistry is a region where the pH of a solution remains constant. In an acid-base titration of a weak acid with a strong base, the pH of the solution increases, levels off through the buffer zone and then increases quickly to reach the equivalence point.
Buffer zones also exist with weak bases and strong acids. Biological processes using enzymes are dependent on the buffer zone to provide the correct pH for the reaction to occur and to protect the enzymes. Enzymes that encounter a pH outsize of their normal range sometimes lose their ability to serve as catalysts for their intended biological function. Manufacturers use buffers in the production of alcohol and in coloring fabric.