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How did Louis Pasteur develop the process of pasteurization?

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Painting by Albert Edelfelt showing Louis Pasteur in his laboratory, holding a glass flask and examining it intently, surrounded by scientific equipment on a workbench. — Louis Pasteur In the 19th century Louis Pasteur's work established the germ theory of disease, proving that microorganisms cause fermentation and sickness, which led to the development of pasteurization, aseptic techniques in medicine, and effective vaccines for diseases such as rabies. (Painting by Albert Edelfelt, 1885.)

Louis Pasteur developed the process of pasteurization in 1863 after being requested by Napoleon III to investigate why French wine was spoiling.1

By applying his expertise in microbes and fermentation, Pasteur discovered that the contamination was caused by microorganisms. To eliminate these spoilage-causing agents, he devised a simple procedure of heating the wine to temperatures between 50–60 °C (120–140 °F). This thermal treatment effectively destroyed the harmful microbes without ruining the product's quality.12

Following this success, Pasteur applied similar rational methodologies to the beer industry, creating techniques to control fermentation and prevent deterioration during transport. Today, this process is widely used to ensure the safety and shelf life of various foods and beverages, most notably milk, by destroying pathogenic microorganisms and inactivating spoilage enzymes.12