Originally published in the "English mechanic and world of science, Volume XXIII" in 1876. 

M. PASTEUR has just published with the title, Etudes sur la Biere, a book which is indeed a book of combat.  For more than fifteen years this eminent chemist has given his attention to fermentations; he has considerably forwarded their study. Extending his views, he has assigned the cause of wine disease to the presence of special ferments. Beer-making has now drawn his attention. He himself avows that he has been jealous to take from Germany the benefit of a superior method; he thinks he has found at least a more economical method. During his long practical studies, always supported by purely scientific researches of the highest value, M. Pasteur has met many adversaries : the work which he publishes now is a common reply to all at once. In every page one feels the liveliness of the contest on a ground which is very near being conquered, but which is not yet wholly in the hands of the victor.
We cannot follow the author in the details of questions of pure science and their industrial applications, which he-treats by turn with the same competence: we can only summarily expose the doctrines which he has tried to make prevailing, and the applications which he has drawn from them with respect to beer making.

The History of Beer

Known in the earliest antiquity beer is an infusion of hops and germinating barley, which is made to ferment, and which rest and decanting afterwards bring to almost perfect limpidity: it is in reality barley wine. Theophrastus, in the second century B.C., already gives it that name, which is quite right. However, there is, between the two beverages, a considerable difference. Grape wine rarely fails, and, once made, keeps generally well. Barley wine, on the contrary, is nice and difficult to make: the best brewer often fails and sees himself forced to throw away the entire produce of an operation. Moreover, beer keeps with difficulty—it is soon altered.

Originally published in the “The Review of reviews, Volume XII” in 1895

The studies on wine prepare us for the “studies on beer," which followed the investigation of silk worm diseases. The sourness, putridity, and other maladies of beer, Pasteur traced to special' ferments of disease,' of a totally different form, and therefore easily distinguishable from the true torula or yeast plant. Many mysteries of our breweries were cleared up by this inquiry. Without knowing the cause the brewer not infrequently incurred heavy losses through the use of bad yeast. Five minutes* examination with the microscope would have revealed to him the cause of the badness, and prevented him from using the yeast. He would have seen the true torula overpowered by foreign intruders. The microscope is, I believe, now everywhere in use. At Burton-on-Trent its aid was very soon invoked. At the conclusion of his studies on beer M. Pasteur came to London, where I had the pleasure of conversing with him. Crippled by paralysis, bowed down by the sufferings of France and anxious about his family at a troubled and uncertain time, he appeared low in health and depressed in spirits. His robust appearance when he visited London, on the occasion of the Edinburgh Anniversary, was in marked and pleasing contrast with my memory of his aspect at the time to which I have referred.