North American India
Fermented extract of corn and wheat flavoured with
Jimson weed contamination and therefore, providing a supply of water, ethanolic fermentation will ensue. The phenomenon of carbon catabolite repression (see Section 3.4.1) ensures that ethanol is still the major product of carbon dissimilation, even under aerobic conditions. The serendipity effect has some other surprising twists. Thus, it is known that the preparation of some native beers that used cereals as a source of extract involved a step where the grains where masticated by the brewer. In so doing the addition of saliva, which contains the amylase, ptyalin, would partially degrade the starch content of the grain and thereby increase the fermentability of the wort. It is interesting to conjecture as to the train of empiricism that culminated in this process!
The beneficial effects of fermentation extend to the bacteriocidal qualities of the product. Ethanol itself inhibits the growth of many micro-organisms and this property is reinforced by the lowering of pH caused by other by-products of yeast metabolism. If the beverage contains viable yeast cells these will ensure that anaerobiosis is maintained and so inhibit the growth of aerobic contaminants. Further antiseptic qualities are introduced by many of the supplementary flavouring agents, for example, hops. In addition, the preparation of many beers includes a boiling step which alone would have a sterilising effect. In historical times, therefore, beer was a useful source of dietary calories, minerals and vitamins but could also be viewed as sanitised water. In medieval times this property was of no small significance when one considers the number of potentially fatal diseases which could be contracted after imbibing polluted water. This is illustrated by the story of Saint Arnold, the patron saint of Belgian brewers, who reportedly saved the inhabitants of a village gripped by a cholera epidemic, by blessing the local brewery and advising them to eschew water and from then on drink only beer (Bell, 1995).
The origins of the discovery of alcoholic fermentation are lost in pre-history. However, archaeological records indicate that brewing has been an organised community activity for at least 5000 years, hence the often quoted comment that production of beer, together with baking, represent the world's oldest technologies. Thus, it is reported that in ancient Mesopotamia some 40% of cereal crops were used for brewing (Corran, 1975). It appears that in antiquity the skills of malting cereals, to release fermentable sugars from starch, were also discovered (Samuel & Bolt, 1995; Samuel, 1996). It must be assumed that this also was an accident, although perhaps one that is more difficult to explain. Corran (1975) speculates that it may have been based on the observation that cereal grains used for brewing which had been stored under wet conditions would potentially give an increased yield of alcohol. It seems likely that such experience would have provided a powerful stimulus for further experimentation. However, the same author also contends that primitive malting may also have arisen as part of ordinary cooking, where it would have rendered the grain more nutritious and digestible. Whatever the truth, it is certainly the case that the discovery of malting marked the beginnings of brewing recognisably modern beers and that this probably occurred in the Middle East sometime after the birth of agriculture in 6000 bc.
The classical civilisations (Greece and Rome) have no history of brewing, since the preferred drink was wine, presumably another skill acquired by happy accident, and dependent on a ready supply of grapes. The rise of modern brewing occurred in the more temperate climates of northern Europe. Possibly some of the skills were acquired from the Middle East, although independent discovery may also have occurred. By medieval times brewing was an everyday and universal domestic occupation usually performed by women, the alewives of yore. Larger scale operations occurred wherever the needs of a sizeable community required to be satisfied, for example, religious institutions or large households. Thus, in Burton-upon-Trent in the United Kingdom, the abbey founded in the eleventh century had a brewery whose product formed the reputation of this town as a centre of brewing excellence. Similarly the high regard paid to Belgian beers owes much to the skills of the medieval abbey brewers. Fortunately a few of these monastic breweries have survived and still produce the specialist bottle-conditioned Trappist beers.
Beer production on large country estates could be prodigious, reflecting the fact that it formed the staple drink of all classes. Thus, Sambrook (1996) records that ale consumption in single medieval noble households were usually in the range of 7501500 hi per annum. In such households, the daily allowances for each servant was one gallon (3.8 litres)! The origins of the inn or tavern are unrecorded but they were certainly in existence in the United Kingdom during Roman times. However, the widespread use of beer, as opposed to wine, was probably heavily influenced by later Saxon and Danish invasions (Hackwood, 1985).
The benefits of using hops in brewing were known in antiquity and records exist detailing their cultivation in ancient Babylon (Corran, 1975). This knowledge was passed to Europe; however, initially hops were used in conjunction with other herbs such as rosemary, bog myrtle, sweet gale, coriander, caraway, nutmeg, cinnamon, ginger, milfoil and yarrow. Mixtures of such herbs were called 'gruit' and with local variations were incorporated into beers to add flavour and improve keeping qualities (Forget, 1988). Widespread use of cultivated hops, as opposed to gruit, began in Germany, probably in the tenth century, and from there spread to the rest of Europe. Hops were introduced to Kent in England probably by Flemish weavers in the fifteenth century (Lawrence, 1990). Apart from altering the flavour of beer, the preservative qualities of hops allowed weaker beers with longer shelf-lives to be brewed since it was no longer necessary to rely entirely on the anti-microbial qualities of ethanol.
The arrival of hops in the United Kingdom marked a need to distinguish between ale and beer. The latter was taken to refer only to a hopped fermented malt beverage; however, as Sambrook (1996) discusses, other meanings were also used. Thus, when commercial and domestic brewing were parallel operations, the product of the town brewery was often termed beer and the home brewed material as ale. In another sense, ale was used to describe the product made from the first strong worts, whereas the term beer derived from subsequent weaker worts, hence the expression 'small-beer'. There was resistance to the use of hops in most countries of Europe, primarily because of vested interests. Thus, purveyors of ales and gruit all had good commercial reasons to discourage production of hopped beers. Ultimately, these sanctions were unsuccessful and in response to public demand the use of hops became the norm.
The mineral composition of local water supplies was influential in the development of centres of brewing excellence in particular areas. For example, the soft waters of Pilsen and Munich are required for brewing lager beers and the water at Burton-upon-Trent with high levels of gypsum is optimal for the production of pale ales by top fermentation (Section 2.3.3). Unlike Burton-upon-Trent, the natural well waters of Scotland are soft and high-quality lager beers have been produced in Glasgow since the late 1880s (Donnachie, 1979). Again, as with much of the history of brewing, it must be assumed that the significance of water composition was based on empirical observations; however, as discussed later, although the causes were unknown it was the major reason for the establishment of brewing in particular areas.
The origins of the use of bottom fermentation to produce lager beers are also unknown but Corran (1975) considered that it probably began in Bavarian monastic breweries. It must be assumed that by chance a bottom-fermenting strain of yeast was selected and was retained because of the superior nature of the product. A natural supply of soft water provided another vital ingredient, although temperature was also important. Lager brewing requires low temperatures and unlike the United Kingdom, with its heritage of top fermentation, this was to be found in continental Europe, at least during the winter. Before the advent of refrigeration the requirement for low temperatures made bottom fermentation a seasonal activity. Thus, in Bavaria, bottom fermentation was discontinued during the summer months and top-fermented beers using higher temperatures were produced instead (Corran, 1975). From a another standpoint, the preponderance of ale production in the United Kingdom can be attributed directly to the effects of the Gulf Stream. According to Miller (1990) it was a Bavarian monk who in 1842 smuggled the first bottom-fermenting yeast into Bohemia and thereby laid the foundation for the production of Pilsener lager beer in the Czech Republic. Soon after this the same style of brewing spread from Munich into the rest of Germany and from there to the remainder of Europe and Scandinavia.
The development of industrial brewing and the decline in domestic production was due to many factors. Beer and ale ceased to be the universal drink of all classes when other beverages became available and consequently there was less need to provide a constant domestic supply. Tea and coffee were introduced to Britain during the middle of the seventeenth century, providing an alternative to beer. Initially both tea and coffee were affordable only by the wealthy; however, in Britain, the cost of tea fell dramatically in the mid-nineteenth century and this period coincided with the greatest decline in domestic brewing. The rise of the public house, the reduction in the number of servants and the discontinuation of the use of beer as part of wages also contributed.
In the United Kingdom, the development of the commercial brewery was part of the Industrial Revolution of the eighteenth and nineteenth centuries. The resultant urbanisation provided a mass market for the product and the introduction of methods of large scale production, together with a ready supply of labour, provided the means for satisfying the need. According to Gourvish and Wilson (1994), in 1830 domestic brewing accounted for 20% of total output in the United Kingdom. In the same year single outlet breweries had 45% of the beer market. By 1900 both of these segments of UK brewing were negligible but between the same years the annual production of commercial brewers rose from less than 13 million hi to nearly 50 million hi.
Initially commercial brewers provided for the needs of local communities. However, the development of efficient methods of freight transport allowed further expansion. Naturally this occurred in recognised centres of brewing. The experiences of Burton-upon-Trent provide an example of these developments as described by Owens (1987). From monastic beginnings brewing in Burton passed into the hands of a local noble family, the Pagets, after the dissolution of the abbey in 1540. The Pagets fostered the brewing tradition, and, by 1604, 46 Burton brewers served the local community as well as meeting the demand of London consumers, via road carriers, for the then-fashionable Burton beer. In the eighteenth century the development of navigable waterways between Burton and Hull, on the east coast of Yorkshire, provided a means of exporting beers to satisfy a growing market in the Baltic. In addition, the links provided by other canals fuelled an ever-increasing domestic trade.
By 1793 the Baltic trade had ceased due to the Napoleonic wars and other markets were required. This was achieved by export of pale ale to India. By 1832, two Burton brewers, Bass and Allsopp, were shipping nearly 10 000 hi of pale ale to Calcutta. A consequence of this was that the qualities of the beer became widely valued within Britain and this led to a much increased domestic market.
The importance of the national home sale trade was facilitated by the growth of the Victorian railway system. In the period 1831 to 1868, the capacity of Bass increased from just under 19000 hi to nearly 880000 hi per annum. The realisation of the significance of the local water supply in Burton to the brewing of pale ales led many London brewers to commence operations in Burton. By 1888 Owens (1987) records that 32 brewers were in operation within the town, employing a work force of more than 8000 and producing an annual output of nearly 5 million hi.
The spread of European brewing techniques to the rest of the world was fuelled by emigration and colonisation. The type of beers produced would have been those associated with the countries of origin of the settlers. Thus, because of the empire building activities of the British, the brewing of top-fermented beers became common in many parts of the world, only to be superseded at a later date by lager beers. A result of this expansion was that in many countries the brewing of European-type beers by settlers coexisted with the production of the native beers made by the original inhabitants. The supplies of European beers could also be augmented by imported products.
For example, brewing of lager beers was introduced to Japan and other Asian countries in the late 1800s, when barriers to foreign trade were dropped. Initially the breweries were managed by western in-comers as a separate industry to the indigenous production of Japanese rice beer, saké. By 1901, over 100 Japanese breweries were in operation. In subsequent years the number of breweries fell, and, as in other countries, the industry became dominated by fewer larger companies and in this case, managed by native Japanese brewers (Inoue et al., 1992a).
In America, brewing was introduced into Virginia in 1587 by Walter Raleigh. The first commercial brewery opened in Charlestown, Massachusetts in 1637 (Corran, 1975). At first the majority of American brewing was concentrated on the east coast and was based on British procedures. Later, waves of German and Dutch immigration, from 1850 onwards, initiated lager beer production and this style of beer eventually became predominant. The change from top fermentation to bottom-fermented lager was accelerated when commercial refrigeration plant became available. Interestingly, the rise of Milwaukee as a centre of lager brewing was in part a consequence of the availability of large quantities of ice from the adjacent Lake Michigan.
The development of brewing, both domestic and commercial, was obviously based largely on empirical experience and as such a successful outcome owed much to the art of the brewer. However, what of the elucidation of the underlying science? With respect to fermentation, three discoveries were crucial to the development of the modern industrial process. First, an appreciation of the true role of yeast; second, identification of the causes of spoilage; third, invention of apparatus to allow accurate monitoring and control of the fermentation process.
The introduction of methods of improved monitoring of fermentation was an essential adjunct to the increases in scale associated with industrialisation. In particular there was an obvious need to be able to monitor the progress of the various processes involved. Two innovations of note are the introduction of the thermometer by Combrune in 1768 and the saccharometer by Richardson in 1784.
The story of the establishment of the biological nature of ethanolic fermentation in effect marks the end of the old alchemical theories and the beginnings of modern microbiology and biochemistry. Thus, this discovery was of profound significance to the development of all of the biological sciences. In the early stages of this history, as befits the fundamental nature of the subject, the major protagonists were in most part what would now be described as main-stream academics. Since this same group produced most of the written records, they are usually credited with the discovery of the vital nature of yeast and its role in the biochemistry of fermentation. However, as will be seen, a few brewers have left records that indicate that everyday observations and experience had already suggested to some that yeast was more than just an inanimate by-product of fermentation. It is interesting to note that an early English name for yeast was Godisgood (Keller et al., 1982) which perhaps supports the view that common bakers and brewers had suspicions that it played more than a passing role in fermentation. In later years when the biological nature of fermentation was known and fully accepted the major brewing companies themselves employed specialist scientists and it can be shown that for a brief period of time this group of people were very much in the vanguard of fundamental research.
The discovery of the nature of fermentation is described by Florkin (1972) in his excellent A History of Biochemistry and the subject is also well documented by Anderson (1989, 1991, 1993), Curtis (1971) and Stewart and Russell, (1986).
The word fermentation derives from the Latin fevere, to boil. According to alchemical theory fermentation was an active separation process and thus, in the case of alcoholic fermentation, the ethanol was already present but did not become evident until impurities, in the form of yeast and carbon dioxide, became separated. It was recognised, however, that sugar was required. Subsequently the idea was born that fermentation did involve the formation of new products but these changes were taken to be purely inanimate and involved a chemical simplification. For example, in 1697, Georg Ernst Stahl, the founder of the phlogiston theory of combustion, concluded that the violent activity and heat generation associated with fermentation 'loosened' the particles present in the medium and allowed the formation of new products. Later, towards the end of the eighteenth century, the chemical nature of fermentation was given added credence by Lavoisier who, on the basis of elemental analysis, calculated a stoichiometric relationship between sugar and the products of fermentation (as he believed) ethanol, carbon dioxide and acetic acid.
In 1810, Gay-Lussac proposed that oxygen was the active ingredient that initiated fermentation. Thus, he considered that the oxygen reacted with the sugary liquid to produce the ferment. This conclusion was based on experiments in which he observed that foodstuffs sealed in bottles and heated in boiling water spoiled, or fermented, only when air was admitted. He also performed the key experiment showing that fermentation could be stopped, even after the addition of air, by boiling. Unfortunately this was interpreted as an effect in which the heat altered the ferment produced by the action of oxygen on the liquid into an inactive form. Yeast was discounted as being part of the process on the basis of insolubility. Gay-Lussac did establish that during fermentation one molecule of glucose gives two molecules each of carbon dioxide and ethanol and this equation still bears his name.
The true role of yeast in fermentation was established, apparently independently during the early nineteenth century, by a Frenchman, Charles Cagniard-Latour, and two Germans, Theodor Schwann and Friedrich Traugott Kiitzing. However, before mention of their work it should be noted that the microscopic nature of yeast cells were of course first recorded by Antonie van Leeuwenhoek, using one of his own microscopes, to examine fermenting beer. His observations were published in a letter to the Royal Society in 1680 (given in translation by Chapman, 1931). Chapman makes clear, however, that although van Leeuwenhoek undoubtedly saw yeast cells in the beer he had no appreciation of their role. Cagniard-Latour also made direct microscopic observations of growing yeast cells but with the benefit of the more advanced instruments available in the 1830s. He noted that the cells proliferated by the formation of buds and concluded that this was evidence of life and went on to show that the presence of yeast cells was necessary for fermentation to occur.
Schwann examined alcoholic fermentation as part of a larger investigation to disprove the theory of spontaneous generation. He had already shown that putrefaction of infusions of meat did not occur when it was heated and air was excluded. Furthermore, the onset of spoilage, which occurred when air was admitted, was prevented if the air was first heated. His interest in alcoholic fermentation was aroused because of Gay-Lussac's contention that oxygen was the causative agent. In fact, Schwann was able to show that contrary to Gay-Lussac's assertion, heated air was essentially unchanged since it remained able to support life, in the form of a frog. He also described the morphology and growth of yeast cells, which he termed 'Zuckerpilz' and noted that their fermentative activity was destroyed by heating.
Kiitzing also used microscopic observation as the basis of his conclusion that yeast was the agent responsible for alcoholic fermentation. Thus, he wrote 'it is obvious that chemists must now strike yeast off the role of chemical compounds, since it is not a compound but an organised body, an organism' (Anderson, 1989).
Despite the apparently strong evidence of Cagniard-Latour, Schwann and Kiitzing for the role of yeast in fermentation, eminent members of the pro-chemical lobby remained in their entrenched positions. In particular, Jons Jacob Berzelius, a Swedish chemist and leading opinion former (he was largely responsible for the universal adoption of the atomic theory and established the current system of chemical notation), ridiculed the suggestion that yeast was animate. This polarisation of views was exacerbated by a scurrilous piece of satire published anonymously in the prestigious Annalen der Pharmacie but actually written by one of its editors, Justus Liebig, and his close friend Friedrich Wohler, a former pupil of Berzelius. This article depicted yeast cells in the form of eggs which on contact with sugar, hatched to form microscopic creatures. These ate the sugar and then expelled alcohol from the digestive tract and excreted carbon dioxide from the bladder, which took the shape of a champagne bottle. Liebig believed in the existence of a vital force which held the atoms and molecules of living organisms together. After death these components were held together only by weak forces which could be overcome by another stronger force such as contact with oxygen or heat. Fermentation or putrefaction of sugary solutions was brought about by the oxygen acting on unspecified nitrogenous substances, which were mysteriously transformed into inducers of fermentation.
As Anderson (1993) discusses, whilst this controversy was raging during the middle of the nineteenth century, a few scientists associated with the brewing industry accepted the role of yeast in fermentation. However, it required Pasteur to convince the academic mainstream. Undoubtedly this was made easier by his then international reputation. Anderson (1995) has also made an excellent chronicle of this part of the story. Pasteur came to consider fermentation whilst occupying the Chair of Chemistry at Lille. One of his interests was a study of the optical activity of molecules, an attribute he associated with living organisms. At Lille, he detected optically active amyl alcohol in the product of beet juice fermentations and, therefore, he concluded that the process must be in some way animate.
Using the famous swan-neck flasks Pasteur augmented the earlier findings of Schwann and proved conclusively that putrefaction occurred as a result of airborne microbial contamination and not via spontaneous generation. His initial studies with wine and latterly with beer confirmed that yeast cells were the causative agents of fermentation. Crucial to the development of controlled and hygienic brewing and oenology, he extended this conclusion to show that infections by other specific microorganisms were the cause of 'diseased' fermentations. In his Etudes sur la bière, published in 1876, he produced designs for hygienically designed industrial scale fermentation vessels, which included plant for aerating wort.
Pasteur is generally credited with introducing practical scientific methods to brewing. For example, introducing the microscope for use as a tool for routine quality control. Although there is truth in this, as Anderson (1995) points out, the microscope had been in common use in some United Kingdom breweries for some time prior to Pasteur's visitations. Nevertheless, it was the work of Pasteur that finally laid to rest the non-animate theories of fermentation. Whatever the precise chronology, it is certainly true that the late Victorian age brought a bloom of scientific enterprise to brewing. Many of these scientists were of the first rank academically and had international reputations to match.
In Burton-upon-Trent, in the United Kingdom, Horace Tabberer Brown, his halfbrother, Adrian John Brown, Cornelius O'Sullivan and Johann Peter Griess all contributed greatly to understanding the scientific basis of fermentation and other aspects of brewing. These four, together with four other locals, formed an informal scientific discussion group, the Bacterium Club in 1876. Later in 1886 this became the Laboratory Club, and, as the membership increased, the Institute of Brewing in 1890. It is noteworthy that, due to the influence of scientific discovery, brewing in Burton was transformed from a seasonal October to April activity into an all-year-long process.
Although the effects of the Industrial Revolution were felt most in the United Kingdom, the advance of science in brewing was also evident in other parts of Europe during the late nineteenth century. In Germany, educational courses for brewers were founded at Weinstephan in 1865. These evolved into an Academy for Agriculture and Brewing in 1895. This was incorporated into the Technical University of Munich in 1930. In 1883, in Berlin, the Versuchs-und Lehranstalt für Brauerei (VLB) was established as a centre for practical and scientific research in brewing. In Copenhagen in 1875, J. C. Jacobsen, the founder of the Carlsberg brewery, founded the laboratory of the same name. The following year this became the Carlsberg Foundation under the control of the Royal Danish Academy of Sciences. Of the many eminent alumni of this institute, two are of particular relevance to yeast and fermentation. In 1935, Ojvind Winge demonstrated sexual reproduction in yeast, and, later, in 1937, Men-delian segregation, thereby opening the possibility of developing improved yeast strains using classical genetic breeding techniques. Before this, in 1883, E. C. Hansen introduced pure yeast cultures to brewing (Curtis, 1971).
Emil Hansen applied to fermenting worts the relatively new methods of the medical bacteriologist Robert Koch of isolating pure cultures using solid media. He noted that a number of distinct yeast strains could be isolated from turbid (or infected) beer. Of these only one, when cultivated and inoculated into fresh sterile wort, produced satisfactory beer. Hansen had, therefore, extended the observations of Pasteur that not all yeasts could be classed as beneficial and indeed some strains were responsible for the so-called diseases of beer. Hansen's brewing yeast strain was christened Carlsberg Yeast Number 1 and was used successfully for commercial brewing. This was accomplished using specially designed pure yeast propagation plant. Pure yeast cultures were soon exported to several other European centres of lager brewing where they were used with much success. Thus, the first propagation plant was installed into the Copenhagen Carlsberg brewery in 1884 and similar plant the following year at the Heineken Brewery in Rotterdam. The latter helped promulgate pure yeast brewing since they supplied yeast to several German brewers.
In the United Kingdom Hansen's yeast propagation plant was first installed at the Worthington Brewery in Burton-upon-Trent by G. H. Morris, a colleague of Horace Brown. It was not a success and it was mistakenly claimed that British top-fermenting ale yeasts were unsuited to this approach. The problem was that beers in cask failed to develop sufficient condition. In fact, it seems likely that much of the secondary fermentation in the cask was brought about by contamination with wild yeast, postfermenter. In addition, since many, if not the majority, of British brewers used mixed cultures it was considered that it would not be practicable to duplicate this with a pure yeast culture plant. The British prejudice not to adopt Hansen's principles persisted for many years and it was not until the mid-1950s that modern yeast culture plant came into common use.
The burgeoning of scientific research in brewing exemplified by the Victorian era ended with World War I and the subsequent depression. Prohibition in the United States and Finland, together with slumps in trade in Germany and much of Europe, heralded the beginning of a period of austerity both economically and scientifically which lasted through to the beginning of World War II. The post-war period marked the start of a new era of modern science. During this time many brewing companies opened or enlarged their own research and development facilities. However, because of the applied nature of the research, these have not offered the opportunities for in-house scientists to establish reputations of the same magnitude as the Victorian 'greats'. No doubt this was also due to a great deal of the work being shrouded in the cloak of commercial secrecy.
On the positive side the post-war period has seen a move towards greater international co-operation. Thus, the Brewing Industry Research Foundation was founded in 1951. In the last decade this organisation has added 'International' to its name and is currently known as Brewing Research International (BRi). Other research associations such as the American Society of Brewing Chemists (ASBC), the Master Brewers Association of America (MBAA) and the Japanese Association of Brewing Chemists (JASBC) were formed at a similar time. To further international co-operation in brewing science, the European Brewing Convention (EBC) was formed in 1947 by Philippe Kreiss. This has established links with the brewing industry in most of the countries of Europe as well as the United States and Japan. In addition to promulgating advances in brewing science, the EBC and the other sister organisations have established standard methods for measurement and analysis.
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