Louis Pasteur and the Science of Beer Making

Prost! On August 4, 2023, we’re having another #ArchivesHashtagParty, and this month’s focus is #ArchivesScience, so we’re turning to food science. Today’s post from Caroline Shanley in the National Archives History Office looks at a patent from Louis Pasteur on beer-brewing technologies.

Brewing beer has been enjoyed by many cultures for thousands of years. In its rawest form, beer has only two key ingredients: water and a fermentable yeast such as wheat or rice. From there, it’s up to the manufacturer or brewmaster to add other variants such as hops, malt, fruit, or other ingredients that might enhance the flavor.

The Industrial Revolution in the 19th century ushered in a new era of beer making, but the biggest problem with beer was its limited shelf life. In the modern day we have refrigerators, but hops enthusiasts of the 19th century could not easily keep food and beverages in cold storage. Beer’s short shelf life also prevented any kind of mass production and trade between states and countries. After a while, it would spoil.

It was not until French chemist Louis Pasteur began investigating the process of fermentation that the beer industry changed significantly. Pasteur was a renowned scientist, interested in microorganisms, food science, and even medicine. 

Most people know Pasteur for his eponymous “pasteurization” process as applied to milk. But in reality, Pasteur was studying beer. The National Archives possesses the thousands of patent applications submitted to the Patent and Trademark Office, including those from Louis Pasteur himself. 

In a broad sense, patents protect the ideas of scientists and inventors by ensuring that their innovations are legally actionable if somebody tries to imitate or steal them. This is the principle of exclusivity. The foundation of American patent law is enshrined in the Constitution under Article I, Section 8, clause 8, which allows Congress “[t]o promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries.” 

The patent-granting authority has chiefly rested with the federal government, though some states in the early republic granted their own patents. One big change in the 19th century was the ability for non-U.S. citizens to file for patents, which came with the passage of the Patent Act of July 13, 1832.

In Patent Case File No. 141,072, Improvement in the Manufacture of Beer and Yeast, Pasteur lays out how, by heating the beer to a certain temperature, he could eliminate the bacteria from the yeast that would cause the beer to rot. Like his contemporaries, Pasteur wondered why sometimes wine would turn sour and why beer would go bad. He was the first scientist to propose the idea that yeast was alive, and its fermentation could lead to bacterial growth.

Pasteur’s patent submission reflected a broader trend of beer consumption in the 19th-century United States. A big piece of the rise of popularity in beer was the influx of German immigrants, with about five million Germans coming to the United States between 1820 and 1900. Among these immigrants were big names like Pabst and Busch. 

Breweries started springing up in various states and territories, with approximately 140 operating around 1840. Initially, beer making was a hyper-local market. This meant the beer you consumed likely came from one’s immediate community or, in some cases, was brewed at home. Pasteur’s innovation for prolonging the beverage’s shelf life sparked interstate commerce, giving rise to breweries’ ability to export their beers. 

Now, many Americans who enjoy beer likely try ones that were brewed hundreds or even thousands of miles away. So next time you’re having a nice cold one, you have a 19th-century French germ scientist to thank!

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