By Harold McGee
In 1863 the French Emperor Louis Napoleon asked the great chemist Louis Pasteur to study the “maladies” of wine. Three years later, Pasteur published the landmark Etudes sur le vin. Pasteur and others had already demonstrated that yeast is a living mass of microbes, and thus had made it possible to begin to identify and control the kinds of microbes that both make wine and spoil it. But Pasteur was the first to analyze the development of wine, to discover the central role of oxygen, and show why both barrel and bottle were indispensable for making good wine, the barrel for providing oxygen to the young wine to help mature it, and the bottle for excluding oxygen from the mature wine to help preserve it.