Brewer's yeast turns out to be a living organism: Cagniard-Latour, Schwann, Kützing

1836-1838 Life and health observation

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The discovery that brewer's yeast is not a sediment or a chemical reagent but a mass of minute living bodies capable of reproducing themselves, and that alcohol is a by-product of their growth.

The same conclusion was reached independently by three men. The Paris physicist and engineer Charles Cagniard-Latour worked with the finest microscopes then available; the Germans Theodor Schwann in Berlin and Friedrich Kützing in Halle published their observations in 1837. The material came straight out of production: what was examined under the microscope was brewery yeast.

Barnett holds that research on alcoholic fermentation, which led to the understanding of the role of enzymes in metabolism, starts precisely here.

Why this date

Medium for the axis point. The three works are independent and spread out in time: Cagniard-Latour published his first notes on fermentation in 1836 (L'Institut, per the DSB bibliography), his "Mémoire sur la fermentation vineuse" was presented to the Academy on 12 June 1837 and printed in Annales de chimie, 68 (1838), 206-222 (from the bibliography of Jacques Payen's article in the Dictionary of Scientific Biography); Schwann and Kützing published their observations in 1837. The axis year 1837 is that of the presentation of Cagniard-Latour's memoir and of the other two publications. The bibliographic details of Schwann's and Kützing's separate papers could not be verified and are therefore not cited.

What it grew from

• Fermentation as a reproducible practice: beer, bread, wine

  influenced · Confidence: medium

  What was examined was not yeast in general but brewer's yeast, the finished product of a craft: Cagniard-Latour put under the microscope what a brewer kept in his vat and saw reproducing bodies in it.

  Dispute: The confidence is deliberately lowered: the quotation states that the material was brewer's yeast, but does not state that the practice of brewing prompted the research. No direct statement by a historian to that effect was found.

  Link sources

  • Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    Begun as early as 1835, they led him, toward the end of 1836, to see that there was certainly a living substance in brewer's yeast.

  • Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    brewer's yeast is a mass of small globulous bodies capable of reproducing themselves

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

• Microscope and the discovery of the cell

  prerequisite for · Confidence: medium

  Budding cells in a yeast mass can be seen only through a microscope; Payen states explicitly that Cagniard-Latour's work was done with the finest microscopes available.

  Dispute: The second quotation is given as background, not as an assertion of the link: Barnett speaks of the improvement of objectives but, in the text found, does not state that the discovery of 1837 was made possible by them. The link rests on the first quotation.

  Link sources

  • Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026, quotation assembled from fragments

    Reporting on research done with the finest microscopes available, Cagniard wrote, “Ferments… are composed of very simple organized microscopic bodies…

  • James A. Barnett, «Beginnings of microbiology and biochemistry: the contribution of yeast research», Microbiology 149 (3), 557-567 (2003)

    Giovanni Amici (1820), professor of astronomy at Modena, made some of the first microscope objectives to be corrected effectively for chromatic and spherical aberrations.

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong. "Assembled from fragments" means the words do not stand together on the page: we found each fragment separately and joined them with an ellipsis.

What grew out of it

• Liebig: fermentation is transmitted decomposition, not the work of a living thing

  influenced · Confidence: high

  Liebig's theory of 1839 is a direct answer to the conclusion of 1837: first an anonymous skit mocking the microscopical findings, then a purely chemical explanation of his own. According to Payen, Liebig's attacks pushed the view of yeast as a living thing into the background for twenty years.

  Link sources

  • Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    Schwann came to the same conclusion at the same time, but Liebig's violent attacks forced this point of view into the background for twenty years.

  • James A. Barnett, «Beginnings of microbiology and biochemistry: the contribution of yeast research», Microbiology 149 (3), 557-567 (2003) Verified 20 Sep 2026

    Von Liebig and Wöhler went so far as to publish jointly in their journal, Annalen der Pharmacie, an anonymous skit mocking the microscopical findings they rejected.

  • James A. Barnett, «Beginnings of microbiology and biochemistry: the contribution of yeast research», Microbiology 149 (3), 557-567 (2003) Verified 20 Sep 2026

    This was a remarkable event in the history of science and probably held up the development of microbiology for about twenty years.

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

• Pasteur: fermentation is the physiological work of living cells, from the Bigo factory to the Études sur la bière

  influenced · Confidence: high

  Schriefers derives Pasteur's thesis of 1857-1860 directly from the discoveries of the 1830s: Cagniard-Latour's report to the Paris Academy in 1836 and the work of Schwann and Kützing are named as what Pasteur built on.

  Link sources

  • Herbert Schriefers, «Buchner, Eduard», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    On the basis of these discoveries and as a result of his own observations and experiments, Pasteur (between 1857 and 1860) formulated the thesis that alcoholic fermentation was an expression of the vital action of the yeast fungi and inseparably bound to this physiological action.

  • Herbert Schriefers, «Buchner, Eduard», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    In 1836 Cagniard de la Tour had reported to the Paris Academy that yeast consisted of living organisms

  • Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    (It was in 1857 that Pasteur shed light on the question.)

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

• Schleiden and Schwann: the cell as the common unit of structure and growth in plants and animals

  influenced · Confidence: medium

  Schwann was one of the three who showed that yeast is alive, and Florkin derives the cell theory from the same commitment that guided his fermentation work: to replace the 'vital force' with an exact explanation. In the third part of the 1839 book alcoholic fermentation is cited as the model of the metabolism repeated in every cell.

  Dispute: The confidence is deliberately medium. Florkin and Bechtel with Bollhagen connect the yeast work and the cell theory through Schwann's personal programme (a mechanistic explanation of the life of the cell), not through a documented derivation of one from the other. Barnett (2003), who treats the discovery of 1837 in detail, describes both of Schwann's works but asserts no link between them. The link runs only through Schwann's contribution; Cagniard-Latour and Kützing have no bearing on the cell theory.

  Link sources

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    had already been clearly manifested in his studies of muscle, of the mechanism of digestion, and of fermentation. His tendency to introduce a more exact mode of explanation than the current one in terms of the “vital force” culminated in the formulation of the cell theory.

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    In addition, all the parts of the cell itself may be chemically modified during the process of its growth by a “metabolic power” that is an attribute of the cell itself; this is demonstrated by alcoholic fermentation, which provides a representation of the process that is repeated in all the cells of an organism.

  • Marcel Florkin, «Schwann, Theodor Ambrose Hubert», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

    In January 1836 he noted in his laboratory notebook the conclusion that alcoholic fermentation is the work of a live organism.

  • William Bechtel, Andrew Bollhagen, Philosophy of Cell Biology, Stanford Encyclopedia of Philosophy (2019) Verified 20 Sep 2026

    When a year later he argued that fermentation could not occur without the involvement of a whole living yeast cell (Schwann 1837), some critics took Schwann to be claiming that living systems exhibited mysterious vital properties. But for Schwann this was consistent with his mechanist approach—the metabolic processes only occurred when the responsible catalysts were brought together in cells.

  "Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

Node sources

• Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  Begun as early as 1835, they led him, toward the end of 1836, to see that there was certainly a living substance in brewer's yeast.

• Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography (2008) Verified 20 Sep 2026

  brewer's yeast is a mass of small globulous bodies capable of reproducing themselves

• Jacques Payen, «Cagniard de la Tour, Charles», Complete Dictionary of Scientific Biography, Annales de chimie 68 (1838), 206-222. OCR «Annales dechimie», (DECISIONS 036) (2008)

  Mémoire sur la fermentation vineuse présenté à l’Académie des sciences le 12 juin 1837

• James A. Barnett, «Beginnings of microbiology and biochemistry: the contribution of yeast research», Microbiology 149 (3), 557-567 (2003) Verified 20 Sep 2026

  Charles Cagniard-Latour, a physicist and engineer of Paris, Friedrich Kützing, an algologist from Halle and Theodor Schwann (Fig. 2), the great physiologist of Berlin.

• James A. Barnett, «Beginnings of microbiology and biochemistry: the contribution of yeast research», Microbiology 149 (3), 557-567 (2003) Verified 20 Sep 2026

  It would be fair to say that research on alcoholic fermentation, which led to understanding the rôle of enzymes in cell metabolism, started with the discovery by these three scientists that yeasts are living organisms.

"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.

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