Brewing and Science
Karl J. Siebert

Brewing and science have a long historic connection. At the time science was becoming capable of successfully providing understanding and solving problems, brewers had problems and were making money. Some brewers supported studies of brewing problems and the results convinced them that investment in research was worthwhile. Much of the effort was in the biology area, particularly studies of microorganisms (yeast and contaminants), culture techniques, analytical methods for beer and raw materials, and studies of seed physiology and biochemistry (related to malting). Brewers allowed the scientists to report and compare their findings and this lead to scientific societies and publications devoted to brewing science and technology. These arose earlier than most similar organizations and publications in the broader food science arena, and exist to this day.

Early Scientific Developments

Some of the early studies were done by scientists who were or became famous. Leeuwenhoek (credited with inventing the microscope) examined fermenting beer and discovered what we now know were yeast cells; he reported this in 1680. Pasteur did studies in an effort to make French beer as good as German beer; he clarified the nature of bacterial spoilage, and in 1860 made the connection between yeast cells and alcoholic fermentation. Emil Christian Hansen, employed by Carlsberg in Denmark, showed in 1883 that wild (non-culture) yeast, as well as bacteria, could produce spoiled beer. He invented single cell propagation (producing a yeast culture from a single cell of a reference culture, thus assuring uniformity and consistency). Also in 1883 and while working for Carlsberg, Johan Kjeldahl developed the nitrogen assay that was for about 100 years the mainstay (and reference) method for protein determinations in biological materials. Slightly later Søren Sørensen was working for Carlsberg when he developed the concept of pH. W.S. Gosset was working for Guinness on yeast counting when he studied statistical distributions and developed the 't' Distribution and the t-test (published in 1908 under the pseudonym A. Student and known today as the Student's t-test).

Beer Quality

Beer quality is the total of all aspects that the consumer can perceive. A good quality product must simultaneously satisfy expectations in all regards and be consistent. It must have good appearance (nice foam head and appealing color). It must in most cases be free of turbidity, although in a few situations (yeast-containing beers such as Hefeweizen and to some extent cask and bottle conditioned beer) this is expected. The beer should have good aroma, taste and mouthfeel and lack stale or off-flavors. Science has done much to help brewers understand and measure these phenomena, and that has led to raw material specifications and process measurements and procedures that provide sufficient control to in most cases produce beer of desired and consistent quality.