A bottle of wine contains more philosophy than all the books in the world.
—Louis Pasteur
The Jura region of France is draped over a chain of mountains on the border with Switzerland, not far from the mighty Alps. The unique geology of the Jura Mountains attracted nineteenth-century scientists seeking to develop a chronology of Earth’s history, and in 1829 the French geologist Alexandre Brongniart dubbed the second period of the Mesozoic era the Jurassic period in their honor. Despite its great beauty and its fossil-hunting possibilities, the Jura is one of the quieter and less-visited regions of France, which makes it easier to peacefully enjoy its wooded slopes and sky-blue mountain lakes, its ancient small towns, and its sublime local gastronomy. Comté, the most popular cheese in France, is produced here; a top tourist attraction is the enormous bunker beneath the former military fort of Saint Antoine, now known as the “cathedral of Comté,” where more than one hundred thousand giant wheels of cheese gradually acquire their distinctively earthy flavor. Poulet de Bresse is the only chicken to be protected by an AOC, reflecting its reputation as the most delicious poultry in the world. Its succulent flavor is attributed to a combination of terroir and careful free-range breeding practices, which aim to keep the chickens as happy as possible during their short lives.
But perhaps the most intriguing gastronomic discovery in the Jura is its wonderfully unusual wines, which have captivated French wine drinkers for centuries.1 The charming town of Arbois, for example, provides a congenial introduction to the region’s range of AOC wines (including a delightfully oaky chardonnay) and to the unique vin jaune (yellow wine), a golden-hued and intense wine that is produced only in the Jura. Vin jaune is aged for six years, three months in an oaken cask, and its flavors are so complex and unequaled that it has acquired near-mythical status.
Yet Arbois has made a far greater contribution to humanity. It was the childhood home of Louis Pasteur, and its local wines helped him revolutionize our understanding of disease and decay. His story serves as another reminder that the modern world we so often take for granted is actually of rather recent vintage.
Before Pasteur, the wide-ranging effects of microbes were experienced without really being understood. We have already seen, for example, how devastating plagues were attributed to a plethora of fanciful causes, and how processes of fermentation and food decomposition were manipulated without genuine understanding of their exact workings. The scientific revolution produced copious new theories, but the basic idea that specific microbial organisms caused disease and decomposition would have seemed fanciful for most of scientific history. Indeed, even Pasteur, in the mid-nineteenth century, faced furious opposition from doctors and biologists devoted to long-held alternative theories like spontaneous generation (a faulty notion that Pasteur finally debunked for good). Luckily, his tireless experimentation won out, and his scientific innovations would eventually save untold millions of lives.
The role of food and wine in the evolution of Pasteur’s research was evident early on. Arriving as dean of the faculty of sciences at the University of Lille in 1854, he developed an academic program that encouraged students to apply their scientific research to the realities of food and alcohol production, a major industry in this booming northern city. In his first lecture at Lille, he said: “But I ask you, where will you find in your families a young man whose curiosity and interest will not immediately be awakened when you put into his hands a potato, with which he may produce sugar, with that sugar alcohol, with that alcohol ether and vinegar?”2
Pasteur himself was asked to practice what he preached when he was approached by Monsieur Bigo, a local producer of beet alcohol. Some of his enormous vats were producing sour beet juice instead of alcohol, and he asked Pasteur to investigate. Thus began Pasteur’s revelatory research into the process of fermentation. His microscope revealed the presence of microbes that were killing the yeast that normally drove fermentation, and producing lactic acid instead. He was not able to devise a method for killing the microbes, but he advised Bigo to clean the spoiled vats thoroughly and take precautions to prevent the reintroduction of harmful microorganisms. The following year, he published two papers on fermentation, thus inaugurating the field of microbiology.
In 1860, Pasteur published his landmark study on fermentation. His experiments showed more precisely how yeast microbes caused fermentation by converting sugar into alcohol, while different microorganisms were responsible for the contamination that produced soured wines or vinegar instead. By developing methods to limit the effects of these harmful microbes, it finally became possible to scientifically adjust the fermentation process to improve the quality, not just the quantity, of alcoholic beverages. Alcohol production had long been considered an art, not a science, but Pasteur’s empiricism made a persuasive case for rethinking this stance.3
As a result of these studies, Pasteur was asked by the French government to investigate widespread problems with French wines, now the second-largest agricultural product (after cereals) and a major export. Winemaking had expanded greatly since the French Revolution, which had removed many controls on wine production and allowed many inexperienced vintners to join in. The transport opportunities generated by the railroads encouraged the overproduction of popular varieties, and new industrial methods were used to increase the speed and quantity of production. All of this led to a greater incidence of disease and contamination, to the point where the reputation of French wines was suffering internationally. Emperor Napoleon III asked Pasteur to investigate.
Pasteur, naturally enough, returned to his hometown of Arbois, having grown up among its vineyards and long appreciated the virtues of the local wines. Over the course of three summers, he experimented on Jura wines and further developed his microbial theories. Local vintners began coming to his house with their spoiled bottles of wine, seeking advice from the “wine doctor,” and this gave him a ready supply of problem wines to investigate. Contrary to existing belief, Pasteur showed that the souring of wine was not accidental, or inevitable, but the result of external contamination from microbes. He thus recommended limiting exposure to contaminants throughout the winemaking process, but more important, he developed the process of “pasteurization,” which in this case involved briefly heating young wines to 120 to 140 degrees Fahrenheit, which would kill harmful microbes. (This was not quite the same thing as “appertization,” which involved boiling bottles for much longer at even higher temperatures.) Today, pasteurization is used on a wide variety of foods, most notably milk and dairy products. There is no telling how many lives have been saved by this ingenious method of preventing food contamination.
Pasteur’s experiments and advice are credited with saving the French wine industry, a feat he repeated in the 1870s when he developed similar techniques to improve the quality of French beer. In this endeavor, he was driven by his ardent patriotism, recently inflamed by France’s humiliating defeat in the Franco-Prussian War (1870–71). Pasteur became virulently anti-Prussian, refusing to travel in Germany or to allow his works to be published in German—he even refused to drink German beer, then among the most popular in Europe and a major German export. France was known more for its wine than its beer, except in regions such as Alsace and Lorraine, which were lost to Prussia in the war. And so Pasteur saw it as a matter of national honor to elevate the French beer industry, both to enact a measure of revenge on the Prussians and to demonstrate how science could help France best its rivals. He devoted several years toward developing what he called the “beer of revenge,” a product that could match the taste and longevity of German lagers. He disseminated his new production techniques throughout Europe (except, of course, in Germany), and they were widely adopted, immeasurably improving the European beer market. But despite his best efforts to keep the results of his research out of his enemy’s hands, German beer producers eventually followed his recommendations as well, and Germany remained one of the top beer-producing nations for many years. France would obtain a measure of revenge against Germany in the years to come, but never within the realm of beer.
Pasteur even managed to save a French industry he knew nothing about: the profitable and prestigious silk industry in southern France. When silkworm growers across Europe despaired over an unknown disease afflicting their little producers, Pasteur spent several years investigating their plight. He eventually discovered multiple microbes responsible for the crisis and invented new techniques for limiting their access to healthy silkworm eggs.
His experience with silkworms ushered Pasteur into the field for which he is most gratefully remembered, as he began applying his microbial theories to the study of infectious disease. At the time, the idea that disease arose from invisible organisms that could be spread by human contact seemed absurd, but Pasteur doggedly set out to prove the principles of “germ theory” against the hostility of the medical profession. He was an early proponent of medical hygiene, arguing that doctors were actually infecting healthy people by not washing thoroughly enough between patients (this argument only antagonized the medical profession further). He invented vaccines for animal diseases such as anthrax, and then developed a successful treatment for rabies, a horrific disease that was previously a death sentence. This work helped demonstrate the even more radical idea that specific microorganisms were responsible for specific diseases. Pasteur’s research helped launch the field of immunology, which no doubt would have pleased him, as he lost two daughters to typhoid fever (now preventable with a vaccine). It is thanks to Pasteur, and other early proponents of germ theory, that the field of medicine embarked upon an era of radical discovery and innovation, saving untold numbers of lives. The full sum of his scientific contributions remains unmatched, and so it is not surprising that Arbois continues to celebrate his legacy, hosting a museum in his childhood home, a Pasteur walking tour, and a number of reverential memorials.
Ironically, pasteurization is not as popular in France as it is in other parts of the world. We have already seen that many French cheeses are not pasteurized, which gets them into trouble when they try to cross the American border. (Pasteur, who unsurprisingly became a major germophobe, would probably agree with the U.S. Food and Drug Administration on this question.) French wines, the earliest recipients of pasteurization, are today usually unpasteurized, as vintners became convinced that the process did in fact alter the taste. On the other hand, while it is possible to buy normal pasteurized milk in France, many people also buy UHT milk, which has been subjected to even higher temperatures in a process of “ultra-pasteurization.” UHT milk can actually sit for months unrefrigerated in your kitchen cabinet, but it also has a slightly “cooked” flavor that may take a while (or never) to get used to.
Comté is an unpasteurized cheese, but luckily it is allowed into the United States because it has been aged for more than sixty days (legally, to meet the requirements of its AOC, it must be aged at least four months). And it is increasingly possible for Americans to enjoy France’s favorite cheese with its partner in terroir, the wines of the Jura. The intensity of this cheese-and-wine pairing is perhaps incongruous with the calm beauty of the Jura, but it symbolizes rather well the ferocious obsessions of its favorite son, another towering legend of French achievement.