Italy and Austria vied with each other in adopting the seed selected by the Pasteur system. But it was only when Pasteur was on the eve of receiving from the Austrian Government the great prize offered in 1868 to “whoever should discover a preventive and curative remedy against pébrine” that French sericicultors began to be convinced. The French character offers this strange contrast, that France is often willing to risk her fortune and her blood for causes which may be unworthy, whilst at another moment, in everyday life, she shrinks at the least innovation before accepting a benefit originated on her own soil. The French often wait until other nations have adopted and approved a French discovery before venturing to adopt it in their turn.
Pasteur did not stop to look back and delight in his success, but hastened to turn his mind to another kind of study. His choice of a subject was influenced by patriotic motives. Germany was incontestably superior to France in the manufacture of beer, and he conceived the thought of making France a successful rival in that respect; in order to enable himself to do so, he undertook to study the scientific mechanism of beer manufacture.
There was a brewery at Chamalières, between Clermont and Royat. Pasteur began by visiting it with eager curiosity, inquiring into the minutest details, endeavouring to find out the why and the wherefore of every process, and receiving vague answers with much astonishment. M. Kuhn, the Chamalières brewer, did not know much more about beer than did his fellow brewers in general. Very little was known at that time about the way it was produced; when brewers received complaints from their customers, they procured yeast from a fresh source. In a book of reference which was then much in use, entitled Alimentary Substances: the Means of Improving and Preserving them, and of Recognizing their Alterations, six pages were given up to beer by the author, M. Payen, a member of the Institute. He merely showed that germinated barley, called malt, was diluted, then heated and mixed with hops, thus forming beer-wort, which was submitted, when cold, to alcoholic fermentation through the yeast added to the above liquid. M. Payen conceded to beer some nutritive properties, but added, a little disdainfully, “Beer, perhaps on account of the pungent smell of hops, does not seem endowed with stimulating properties as agreeable, or as likely to inspire such bright and cheerful ideas, as the sweet and varied aroma of the good wines of France.”
In a paragraph on the alterations of beer—“spontaneous alterations”—M. Payen said that it was chiefly during the summer that beer became altered. “It becomes acid, and even noticeably putrid, and ceases to be fit to drink.”
Pasteur’s hopes of making French beer capable of competing with German beer were much strengthened by faith in his own method. He had, by experimental proof, destroyed the theory of spontaneous generation; he had shown that chance has no share in fermentations; the animated nature and the specific characteristics of those ferments, the methods of culture in appropriate media, were so many scientific points gained. The difficulties which remained to be solved were the question of pure yeast and the search for the causes of alteration which make beer thick, acid, sour, slimy or putrid. Pasteur thought that these alterations were probably due to the development of germs in the air, in the water, or on the surface of the numerous utensils used in a brewery.
As he advanced further and further into that domain of the infinitely small which he had discovered, whether the subject was wine, vinegar, or silkworms—this last study already opening before him glimpses of light on human pathology—new and unexpected visions rose before his sight.
Pasteur had formerly demonstrated that if a putrescible liquid, such as beef broth for instance, after being previously boiled, is kept in a vessel with a long curved neck, the air only reaching it after having deposited its germs in the curves of the neck, does not alter it in any way. He now desired to invent an apparatus which would protect the wort against external dusts, against the microscopic germs ever ready to interfere with the course of proper fermentation by the introduction of other noxious ferments. It was necessary to prove that beer remains unalterable whenever it does not contain the organisms which cause its diseases. Many technical difficulties were in the way, but the brewers of Chamalières tried in the most obliging manner to facilitate things for him.
This exchange of services between science and industry was in accordance with Pasteur’s plan; though he had been prophesying for fourteen years the great progress which would result from an alliance between laboratories and factories, the idea was hardly understood at that time. Yet the manufacturers of Lille and Orleans, the wine merchants and the silkworm cultivators of the South of France, and of Austria and Italy, might well have been called as enthusiastic witnesses to the advantages of such a collaboration.
Pasteur, happy to make the fortune of others, intended to organize, against the danger of alterations in beer, some experiments which would give to that industry solid notions resting on a scientific basis. “Dear master,” wrote he to J. B. Dumas on August 4, 1871, from Clermont, “I have asked the brewer to send you twelve bottles of my beer.... I hope you will find it compares favourably even with the excellent beer of Paris cafés.” There was a postscript to this letter, proving once more Pasteur’s solicitude for his pupils. “A thousand thanks for your kind welcome of Raulin’s work; Bernard’s support has also been promised him. The Academy could not find a better recipient for the prize. It is quite exceptional work.”
Pasteur, ever full of praises for his pupil, also found excuses for him. In spite of M. Duclaux’s pressing request, Raulin had again found reasons to refuse an invitation to come to Auvergne for a few days. “I regret very much that you did not come to see us,” wrote Pasteur to Raulin, “especially on account of the beer.... Tell me what you think of doing. When are you coming to Paris for good? I shall want you to help me to arrange my laboratory, where everything, as you know, has still to be done; it must be put into working order as soon as possible.”