As the size of brewery operations increased, the need for quality control procedures also increased. Brewers examine beer for contamination by microorganisms, alcohol content, clarity, flavor, and color. Alcohol content is checked by measuring the index of refraction or circular dichroism of the beer, or amount that a light beam is twisted or bent compared to pure water. A refractometer is simple in principle, consisting of a prism, a lens and a light source. Modern refractometers used in the brewing industry are small enough to be held in one hand.
Wahl, Robert, b.1858. American Handy Book of the Brewing, Malting and Auxiliary Trades; a Book of Ready Reference for Persons Connected with the Brewing, Malting and Auxiliary Trades, Together with Tables, Formulas, Calculations, Bibliography and Dictionary of Technical Terms. 3d ed. Chicago: Wahl-Henius Institute, 1908. Crerar 663.3 Q800