Emil Christian Hansen
In the second half of the 19th century, it was common for breweries to have scientific employees in their research and development departments. At this stage, great advances were achieved within the brewing world that allowed the production of beer at a global level and obtain a better quality of the final product. One of the most famous of these scientists was the Danish botanist Emil Christian Hansen (1842 - 1909), superintendent of the Carlsberg brewery laboratory in Copenhagen from 1879 until his death. But before joining Carlsberg, Hansen had a previous research career.
Hansen studied several new species of fungi that grew in the feces of mammals, providing detailed descriptions of their morphology and anatomy, such as Peziza ripensis. His work was published as "De danske Gjødningssvampe" (1876) and was awarded the gold medal from the University of Copenhagen. In subsequent years, he continued to study the biology and variation of fungal species, cultivating Coprinus niveus, C. restrupianus y C. stercorariusIn the latter, he also demonstrated his phototropism. He also described a new family of ascomycetes (Anixiopsis) and later studied fermentation in the zoophysiological laboratory of the University of Copenhagen. His works were published in French and German in 1880.
With this trajectory, the Carlsberg Brewery noticed him, and Captain J. C. Jacobsen hired Hansen to work in his laboratory in 1878. His research continued in this laboratory, this time focused on beer. He studied the causes of beer contamination, reaching the conclusion that they are not always caused by bacteria, as Pasteur maintained, but were also caused by other species of Saccharomyces, called wild yeasts. He discovered that these wild yeasts are very common in the environment and that their contaminations in beer are as common as those caused by bacteria. Hansen concluded that, to avoid infection during fermentation, yeast inocula should be single-strain and conditions should reduce, as far as possible, the passage of wild yeast into the wort. He used the pure culture methods developed by Louis Pasteur, Joseph Lister, and Robert Koch to test his hypotheses, isolating a single yeast cell and producing a batch from that culture.
With his experiments, Hansen showed that there were different varieties and strains of the genus Saccharomyces and that an inoculum of ordinary ferment for a beer was actually a mixture of several species of Saccharomyces. Jacobsen allowed Hansen to use his beer's yeast, called "Carlsberg bottom yeast I", obtained from Munich, which was already mixed with other types of wild yeast. The goal was for Hansen to brew beer on a large scale on an experimental basis. Finally, in 1883, a pure culture was made from a single cell of that yeast to make a new beer that turned out to be excellent and free of impurities, as Hansen expected. Consequently, Jacobsen continued to use those pure yeast cultures for beer production in his factory. With this technique, devised by Hansen, it was possible to separate yeast strains to achieve different sensory profiles in the beer and to be able to select those yeast varieties that best fit each recipe.
During his experiments, Hansen reached other conclusions. He built a special "humid chamber" to be able to follow the development of microorganisms under the microscope and was able to determine the life cycle of other species of Saccharomyces. Because each yeast strain had different results in beer, Hansen assumed that each yeast was physiologically different. He delved into yeast genetics and studied both wild yeast and brewery strains. One of the species of yeast, which was found more frequently and with which beers were obtained with a strong sedimentation and maintaining a good bitterness, he named it Saccharomyces carlsbergensis, later renamed as Saccharomyces pastorianus, in honor of Louis Pasteur. Beginning in 1900, Hansen studied the relationship between Ale and Lager yeast and discovered that changes in the nature of yeast are caused by mutation.
The culture system that Hansen used is the foundation of all modern brewery yeast culture protocols today, and was a major advance in the industrialization of brewery production. In 1890, Emil C. Hansen was a member of the Royal Danish Science Society and obtained large donations from the Carlsberg Foundation and the Brewers Association. His research was published in seven articles under the title "Undersøgelser fra Gjaeringsindustriens Praxis" (1888 - 1892), which were translated into French (1888), German (1888, 1890, 1893) and English (1896).
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