Chapter II: Preface: To English Edition

My first idea of placing before English brewers a translation of “Études sur la Bière” was meagre in the extreme, compared with the final realization of it as it appears in the following pages.

Seeing the vast importance of Pasteur’s work from a practical point of view, after writing a review of it for the _Brewers’ Journal_, I determined to procure, at any rate for the use of my pupils, a literal translation, illustrated by photo-lithographic copies of the original plates, the thankless task of executing this preliminary translation for so limited a number of readers being most kindly and generously carried out for me by my friend Mr. Frank U. Waite, who, being engaged with me at the time in practical brewing operations, shared my views as to the value of the original work.

It was on the completion of this translation that my views and desires expanded. The more I studied the work, the more I was convinced of its immense value to the brewer as affording him an intelligent knowledge of the processes and materials with which he deals, but over and above all this, it was impossible not to feel that the researches of such a devoted and accomplished _savant_ as Pasteur, possessed a scientific interest much wider than their mere relation to the art of brewing would imply. As the work of a skilful chemist and a laborious and accurate observer, such a protracted and careful study of the lowest and simplest forms of life, must necessarily be of first importance to the biologist—to the beginner as an admirable introduction to the study of practical physiology in general, as well as to the more advanced student, from the suggestive light which it throws on the nature of analogous phenomena in more complex organisms.

I determined accordingly _to publish_ the work if I could secure the consent of its distinguished author, but at the same time I felt that the publication of M. Pasteur’s “Studies” in the form in which Mr. Waite had, at my request, translated it, and illustrated only with inferior copies of the original plates, would not be either advisable or just; but that I was bound rather to put the book before the English public in as satisfactory and complete a form as lay within my power. Under these circumstances I was induced to seek the aid of Mr. D. Constable Robb, B.A., of The Oxford University Museum, who, in taking Mr. Waite’s version as a basis, has so elaborated, annotated, and recast it, that I feel bound to say that much of the value of “Studies on Fermentation,” as it now appears, is due to the care that Mr. Robb has bestowed upon the revision that he so kindly undertook; a revision the result of which has created a feeling of confidence in the success of the translation as it now stands, which I could not have had in any mere literal version.

To the practical worker the original illustrations alone, which appear in this version, cannot but be of immense value in the microscopical study of the changes in the liquids with which he deals; whilst the many notes and additions, which are a feature peculiar to the English edition, more particularly the rendering into the equivalents, with which, unfortunately, practical men on this side of the channel are still most at home, of the metric weights and measures and centigrade temperatures, as well as the Index which Mr. Robb has compiled, will, I trust, render the book of still greater service than it otherwise would have been to many of those who may favour it with their attention.

The debt which we English brewers owe to M. Pasteur can hardly be over-estimated, and I must be allowed here to express my personal obligations to that distinguished worker for the permission which allows this translation; and to the French publishers for their help with regard to the interleaved illustrations.

The author’s preface and dedication are, of course, reproduced, the former making it unnecessary for me to refer more in detail to the contents of the translation.

FRANK FAULKNER.

THE BREWERY, ST. HELEN’S, LANCASHIRE, _September, 1879_.

TABLE OF CONTENTS.

AUTHOR’S DEDICATION v

AUTHOR'S PREFACE vii

TRANSLATOR’S PREFACE ix

CHAPTER I.

ON THE INTIMATE RELATION EXISTING BETWEEN THE DETERIORATION OF BEER, OR THE WORT FROM WHICH IT IS MADE, AND THE PROCESS OF BREWING 1

CHAPTER II.

ON THE CAUSES OF THE DISEASES WHICH AFFECT BEER AND WORT.

§ I. Every unhealthy change in the quality of beer coincides with a development of microscopic germs which are alien to the pure ferment of beer 19

§ II. The absence of change in wort and beer coincides with the absence of foreign organisms 25

CHAPTER III.

ON THE ORIGIN OF FERMENTS PROPERLY SO CALLED.

§ I. On the conditions which cause variations in the nature of the organized products existing in infusions 33

§ II. Experiments on blood and urine taken in their normal state, and exposed to contact with air that has been deprived of the particles of dust which it generally holds in suspension 40

§ III. Experiments on the juice contained in grapes 54

§ IV. Wort and must exposed to common air 59

§ V. New comparative studies on the germs held in suspension by the air of different places which are near each other, but subjected to different conditions affecting the production and diffusion of the particles of dust found in them 72

§ VI. Yeast may become dry and be reduced to dust without losing its faculty of reproduction 81

CHAPTER IV.

THE GROWTH OF DIFFERENT ORGANISMS IN A STATE OF PURITY: THEIR AUTONOMY.

§ I. Growth of _Penicillium glaucum_ and _Aspergillus glaucus_ in a state of purity.—Proofs that these fungoid growths do not become transformed into the alcoholic ferments of beer or wine.—Preliminary inquiry into the cause of fermentation 86

§ II. Growth of _Mycoderma vini_ in a state of purity.—Confirmation of our original conjectures as to the cause of fermentation.—_Mycoderma vini_ does not change into yeast, although it may give rise to fermentation 108

§ III. Growth of _Mycoderma aceti_ in a state of purity 121

§ IV. Growth of _Mucor racemosus_ in a state of purity.—Example of life more active and lasting when removed from the influence of air 127

CHAPTER V.

THE ALCOHOLIC FERMENTS.

§ I. On the origin of ferment 143

§ II. On “spontaneous” ferment 182

§ III. On “high” and “low” ferments 186

§ IV. On the existence and production of other species of ferment 196

§ V. On a new race of alcoholic ferments: Aërobian ferments 205

§ VI. The purification of commercial yeasts 219

CHAPTER VI.

THE PHYSIOLOGICAL THEORY OF FERMENTATION.

§ I. On the relations existing between oxygen and yeast 235

§ II. Fermentation in saccharine fruits immersed in carbonic acid gas 266

§ III. Reply to certain critical observations of the German naturalists, Oscar Brefeld and Moritz Traube 279

§ IV. Fermentation of dextro-tartrate of lime 284

§ V. Another example of life without air.—Fermentation of lactate of lime 292

§ VI. Reply to the critical observations of Liebig, published in 1870 316

CHAPTER VII.

NEW PROCESS FOR THE MANUFACTURE OF BEER.

§ I. Preliminary experiments 338

§ II. Method of estimating the oxygen held in solution in wort 353

§ III. On the quantity of oxygen existing in a state of solution in brewers’ worts 364

§ IV. On the combination of oxygen with wort 371

§ V. On the influence of oxygen in combination on the clarification of wort 381

§ VI. Application of the principles of the new process of brewing with the use of limited quantities of air 387

APPENDIX 396

INDEX 403

INDEX TO PLATES.

I. Principal disease-ferments met with in wort and beer 6

II. Appearance under the microscope of the deposit from “turned” beer 20

III. _Torulæ_ in process of development 72

IV. _Mycoderma vini_ functioning as an alcoholic ferment.—Right half, showing appearance of spores just sown; left half, their appearance after an interval of submerged life 116

V. _Mucor_, vegetating submerged, in deficit of air 136

VI. Ferment of _mucor_ 138

VII. Yeast-cells—worn out and dissociated (left), after revival in a sweet wort (right) 148

VIII. Fertile mould-cells from the outer surface of grapes 152

IX. Various examples of the mode of growth of mould-cells from the outer surface of grapes 154

X. One of the ferments of acid fruits at the commencement of fermentation in its natural _medium_ 166

XI. _Saccharomyces pastorianus_, in course of regular growth 168

XII. Ferment-cells from a spontaneous fermentation just starting 184