The Modern Beer Industry

Today, beer has one of the largest dollar values of all fermented food products, with U.S. retail sales in 2002 of more than $65 billion dollars.

Box 9—1. Pasteur, the Origins of Microbiology, and Beer

It is hard to imagine, given the current age of scientific specialization, that one person could have been as accomplished in so many fields as was Louis Pasteur in the latter half of the nineteenth century. He was trained as a chemist and, at the age of only 26, made important discoveries in stereochemistry and crystallography (specifically, while examining tartaric acid crystals in wine). Pasteur then became interested in the not yet named field of microbiology, and devoted nearly two decades of his life disproving the theory of spontaneous generation and establishing microorganisms as the causative agent of fermentation and putrefaction.

His work on vaccines against animal anthrax and human rabies, as well as the establishment of the germ theory of disease, brought Pasteur worldwide recognition and fame (Schwartz, 2001). During his career, Pasteur addressed practical agricultural, food, and medical problems, but did so by relying on basic science ("There is no such thing as applied science, only applications of science," as quoted in Baxter, 2001). He was a meticulous researcher, who rigorously defended the scientific method, saying, "In the field of observation, chance favors only the prepared mind."

There were certainly other well-known scientists of his era, including Schwann, Koch, and Lister, whose works also helped establish the field of microbiology. But the collective contributions of Pasteur led to his recognition as one of the "most distinguished microbiologists of all time" (Barnett, 2000), or as stated by Krasner (1995), the "high priest of microbiology."

Pasteur was already an accomplished scientist, having completed his work on the stereochemistry of tartaric acid, when he turned his attention to solving spoilage problems plaguing the French wine industry. In reality, he was "commissioned" by Emperor Napoleon III in 1863 to serve as a "consultant" and to study these so-called wine diseases. Pasteur correctly diagnosed the spoilage conditions, which he called tourne (mousy), pousse (gassy), and amertume (bitter), as being caused by bacteria. He then showed that the responsible organisms could be killed, and the wine stabilized, by simply heating the wine to 50°C to 60°C.These findings were published in 1866, as "Études sur le Vin."

Nearly ten years later, Pasteur began studying the fermentation of beer, another industrially-important product that was also suffering from spoilage defects.This work led to a second treatise on alcoholic fermentations,"Études sur la bière," published in 1876 (the English-translated version is available and well worth reading). His motivation this time had less to do with his interest in beer (he apparently was not a beer drinker), than it did for his animosity for all things German (Baxter, 2001).

In the early 1870s, France and Germany were at war (the Franco-Prussian War), whose outcome resulted in France having to cede the hop-producing region of Alsace-Lorraine to Ger-many.Already Germany produced the best beer and was the dominant producer in Europe. German beers were better from most English and other beers for several reasons, but mainly because these beers were fermented at a low temperature (6°C to 8°C). The resulting "low beers" (so-named because of the low fermentation temperature, but also because the yeast would sink to the bottom of the tank) were lighter-colored and less heavy than "high beers," but most importantly, they were also better preserved.

Low beers (which we now refer to as lagers) could be produced in the cool winter months, and, provided they were stored cold (in cellars or by ice), be consumed during the summer. High beers (or ales) had to be consumed shortly after manufacture and did not travel well.This situation, in which French beers were at a commercial disadvantage, was intolerable to Pasteur and he was determined to improve French-made beers or as he himself stated, to make the "Beer of the National Revenge."

Pasteur started out by building a brewing "pilot plant" in the basement of his laboratory and by visiting commercial breweries.Then, using microscopic techniques, he showed that specific yeasts were necessary for a successful beer fermentation. He also observed that, based on microscopic morphology, certain contaminating microorganisms were associated with specific

Box 9—1. Pasteur, the Origins of Microbiology, and Beer (Continued)

types of spoilage conditions (or "diseases"). For example, long rod-shaped or spherical-shaped organisms in chains (probably lactic acid bacteria) were responsible for a sour defect. In Pasteur's own words,"Every unhealthy change in the quality of beer coincides with a development of microscopic germs which are alien to the pure ferment of beer"(Pasteur, 1879).The corollary was also true:"The absence of change in wort and beer coincides with the absence of foreign organisms."These foreign organisms had gained entrance into the beer either by virtue of their presence in the production environment or via the yeast (which were used repeatedly and were subject to contamination).

To solve these problems, Pasteur offered several recommendations. He showed that a modest heating step (55°C to 60°C) would destroy spoilage bacteria and render a beer palatable even after nine months. He also emphasized that elimination of contaminants, both environmental and within yeast preparations, would also be effective. Oxygen, Pasteur realized, enhanced growth of spoilage organisms, thus, he devised a brewing protocol that precluded exposure of the wort to air (described in a U.S. patent; Figure 1).

Pasteur demonstrated through actual industrial scale experiments that these strategies would work, and indeed these practices were readily adopted.And although the German beer industry was hardly affected by his personal "revenge," Pasteur's influence on brewing science and microbiology is considerable even today, more than 125 years later.

References

Barnett, J.A., 2000. A history of research on yeasts 2: Louis Pasteur and his contemporaries, 1850-1880.

Yeast. 16:755-771. Baxter,A.G. 2001. Louis Pasteur's beer of revenge. Nature Rev. 1:229-232. Krasner, R.I. 1995. Pasteur: high priest of microbiology.ASM News. 61:575-579.

Pasteur, L. 1879. Studies on fermentation. The diseases of beer, their causes, and the means of preventing them.A translation, made with the author s sanction, of "Études sur la bière" with notes, index, and original illustration by Fran Faulkner and D. Constable Robb. Macmilan and Co. 1879, London and Kraus Reprint Co., New York, 1969. Schwartz,M. 2001.The life and works of Louis Pasteur.J.Appl. Microbiol. 91:597-601.

(Continued)

In 2002, U.S. consumers drank nearly 190 million barrels (1 barrel = 117 L = 31 gallons), with per capita consumption of 81 L or 21.5 gallons per person per year (or nearly forty six-packs per man, woman, and child!).That's also more, on a volume basis, than wine (8 L), juice (34 L), milk (72 L), and bottled water (42 L).Al-though one might assume that this is a lot of beer, beer consumption in the United States is half as much as that of several other European countries (Figure 9-2). For example, per capita consumption (for 2002) in Germany and Ireland was 121 L and 125 L per person per year, respectively, and Austria (109 L) and the U.K. (100 L) are not far behind.The Czech Republic, however, leads all other countries, with per capita consumption of 162 L (2003).

The importance of beer to the world economy is also considerable. In the United States alone, the overall economic impact is estimated to be more than $144 billion, and the industry pays more than $5 billion directly in excise taxes to federal and state government (according to the U.S. Beer Institute). The industry also spends about $1 billion per year for advertisements and promotions.

The beer industry, like many other segments of the food industry, both in the United States as well as internationally, has become highly consolidated. In the past fifty years, many medium

Patent Pasteur 1873 Beer

Figure 1. "Improvement in brewing beer and ale," a U.S. patent (No. 135,245) issued to Louis Pasteur of Paris, France in 1873. The patent is not for "pasteurization," but rather describes a method for excluding air from the boiled wort prior to inoculation with yeast. The resulting beer has improved stability, or, according to the patent, "possesses in an eminent degree the capacity for unchangeableness."

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