A chapter in the book Automated Stream Analysis for Process Control, Volume 2. The brewing process is described and applications of various process control and on-stream measurements (wort gravity fermentation monitoring, yeast concentration, fermenter gas purity, carbon dioxide in ambient air, ozone in water, and in beer: dissolved oxygen, alcohol, original gravity, calories, turbidity, carbon dioxide) are described. Many parameters that are important to quality are not yet suitable for on-line analysis.