In 1854, an Englishman named John Snow figured out that the disease cholera was spread by dirty water. He noted that a cluster of cholera deaths was found around a certain water pump. The authorities removed the handle on the pump, and the epidemic was stopped.
The workers in a nearby brewery did not contract cholera at all, because they were given a daily allowance of beer, and the fermentation process of beer-making involved boiling the water, which killed the cholera bacteria.
John Snow’s deduction was based on an unpopular idea at the time known as “germ theory”. While it is accepted today as a simple truth, it was not believed at the time that disease could be carried by invisibly small “animalcules”.
A few years later, in 1862, Louis Pasteur invented a process to improve the fermentation of beers and wine. The method became known as pasteurisation, and once it was applied to milk and water, it caused a reduction in infant mortality of 75%.
It’s ironic that the person who personally saved three quarters of all dying children in the world did it because he wanted better wine.