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| ISBN-13: | 9781782625612 |
|---|---|
| Publisher: | Royal Society of Chemistry |
| Publication date: | 10/20/2015 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 332 |
| File size: | 8 MB |
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Brewing
By Ian S. Hornsey
The Royal Society of Chemistry
Copyright © 1999 The Royal Society of ChemistryAll rights reserved.
ISBN: 978-1-84755-028-6
CHAPTER 1
The Definition of Brewing
In the broadest sense the word 'brewing' may be defined as 'The combined processes preparing beverages from the infusion of sound grains that have undergone sprouting, and the subsequent fermentation of the sugary solution produced, by yeast – whereby a proportion of the carbohydrate is converted to ethanol and carbon dioxide.'
The modern connotation of the word would imply 'production of beer', in all its various forms – and this is how the author has interpreted it.
From the definition above it can be inferred that any sound grain (usually graminaceous) can be employed provided that the seed has sufficient polysaccharide food-reserve (endosperm). Cereal grains when raw present a relatively unattractive foodstuff and so a combination of soaking in water, or milling and mixing with water, render products which are far more palatable. These, initially crude, processes have undoubtedly provided the basis for the malting, brewing and baking industries that we know today.
For a variety of reasons barley has become the grain of choice for the brewer, whilst wheat is preferred by the baker.
THE ORIGINS OF BREWING
Enough scientific and archaeological evidence has now been gleaned that it is in order for us to believe strongly that what we now know as 'beer' was first produced in the late fourth millennium BC by the Sumerians in southern Babylonia. The Sumerian civilisation was situated in Lower Mesopotamia – in the alluvial plain between the rivers Tigris and Euphrates – and it was one of the earliest literate civilisations known. The world's oldest recipe, written on Sumerian clay tablets, is for the making of beer; the Sumerians were known to be great beer drinkers. Another early tablet consists of a hymn to the beer goddess, Ninkasi, whose very name means 'the lady who fills the mouth'. According to Cahill, 'Ninkasi was brewer to the Gods themselves', she who 'bakes with lofty shovel the sprouted barley', who 'mixes the bappir-malt with sweet aromatics', who 'pours the fragrant beer in the lahtan-vessel, which is like the Tigris and Euphrates joined'.
One school of thought attributes the transformation of Man from nomadic hunter–gatherers, to sedentary, crop-growing peoples, to the accidental discovery of the physiologically interesting beverages that resulted from fermented moist wheat and barley. The theory, championed by Dr Solomon Katz of the University of Pennsylvania, propounds that the 'mood-altering' and nutritional properties of these new beverages provided the motivation for a primitive form of agriculture which would have given the populations indulging in it a less strenuous way of life. Dr Katz goes on to propose that the initial discovery of a stable way to produce alcohol provided the stimulus for people to collect different seeds, to cultivate them and try to improve crop characters.
It soon became obvious that air was detrimental to these fermented brews and, thus, one saw the development of narrow-necked storage vessels common in archaeological sites in Mesopotamia. Such vessels, it is surmised, were designed to keep air out and carbon dioxide in.
One of the most thoroughly investigated sites is at Godin Tepe in the Zagros mountains of what is now Iran. There is evidence that the neighbouring Sumerians exploited this area for some of their essential commodities – and brought their beer-making knowledge with them. There were numerous examples of carbonised six-rowed barley excavated together with fragments of pottery jars with unique criss-cross grooving on the inner surfaces. It is thought that these grooves were designed to retain the sediment from the beer after storage. Chemical analysis of sediment found in the grooves indicated the presence of calcium oxalate, a principal (insoluble) component of 'beer-stone'. As the modern brewer knows well, beer-stone is an inorganic, scale-like, deposit that accumulates in fermentation vessels and beer storage tanks. Oxalic acid is present in trace amounts in malt, and combines during the mashing stage with calcium ions to form the insoluble salt. Ancient jars known to have contained wine, cider and mead do not show any evidence of calcium oxalate deposits. The pattern of grooving on the inner surface of the jar fragments bears great resemblance to the Sumerian signs for beer, called kaš (Figure 1.1).
An extensive collaborative study between archaeologists from the University of Cambridge, and Scottish and Newcastle (now Scottish Courage) Brewery, under the auspices of the Egypt Exploration Society, has produced an insight into how the ancient Egyptians carried out their fermentation technology 3000 years ago. Studies concentrated on two sites on the River Nile: Armana (some 200 miles south of Cairo) and Deir el-Medina; both sites dating to the period known as the New Kingdom (1550–1070BC). Because these sites are outside of the flood-zone of the Nile, the arid climate has allowed desiccated botanical and other biological remains to persist until the present day.
Beer and bread were the most important dietary items of the ancient Egyptians; as evidenced by the plethora of written records concerning the production and consumption of these products. Beer was used as currency at this time, and everyone, from the Pharaoh downwards, drank it. No meal was complete without it and it played a key role in ritual and religious practice, as the number of brewing-related illustrations on the walls of tombs will testify. It has even been suggested that the pyramids were built on a diet of bread and beer! A wide variety of beer types are documented from this period. What are the differences? It is likely that varying categories of beer served the needs of different classes in the population. Archaeological evidence shows that barley was certainly used for brewing, and so was Emmer wheat, which was the dominant cultivated crop throughout much of the Old World. The two grains were, in some products, used in conjunction which could partly explain the variety of beers produced.
With the aid of scanning electron microscopy, Samuel has demonstrated that some grains were sprouted (malted!) before being crushed and used for brewing; the starch grains from such recovered samples showing the characteristic pitting caused by enzymic attack. Unsprouted grains were also used and these appeared to be cooked in hot water before being fermented. There was also evidence of roasted grains being used, presumably to impart colour and flavour to the product. The abundance of lactobacilli from certain brewing sites indicates that these organisms were involved in fermentation as well as yeasts.
As a result of the direct evidence obtained from the area, Samuel proposed a model for New Kingdom brewing (Figure 1.2).
Some of the earliest fermented products in Egypt were very thick in consistency and were called 'boozah', whilst later, slightly more refined, beverages were known as 'hekt'.
The sites around Armana are believed to be within the boundaries of the lost Sun Temple of Nefertiti (i.e. these were Tutankhamun's breweries), and in 1996 the Scottish and Newcastle Breweries (now Scottish Courage), using Samuel's brewing model, re-created this ancient style of beer. Specially grown Emmer wheat was malted for the project, which resulted in a highly distinctive bottled beer called Tutankhamun Ale.
Brewing flourished in Egypt until the end of the eighth century AD when Moslem Arabs conquered the region (the Koran forbids the making, sale and drinking of alcoholic beverages), but the art of brewing had spread far beyond the confines of the Middle East; traders to and from the region gleaned the essentials of beer-making and thus the techniques were disseminated. It is to be assumed that it was via traders that the beer culture reached the British Isles. Certainly, the Romans found beer to be in production here when Julius Caesar invaded in 55BC. They also found that there were cereal crops under cultivation in certain areas, again emphasising the importance of the sedentary way of life in the gradual civilisation of mankind. At that time, however, mead and cider seemed, according to Roman records, to be far more prevalent beverages over here. The word 'beer' is thought, by some authorities, to be derived from the ancient English word 'beor', which meant 'inferior mead'. Records are scarce from the Dark Ages, but we know that during mediaeval times brewing was more or less confined to monasteries, both in the British Isles and continental Europe. By the thirteenth century there were hundreds of monastic breweries in northern Europe, each supplying the local community with its wares, and this was a convenient way of raising funds for ultimately more saintly purposes! A few of these monastic brewing sites still exist today in Belgium and the Netherlands. Within these religious communities considerable attention was given to improving the quality of the end-product. Many of our present day beer styles originated from these times. For example, Bavarian brewing monks noticed that some yeasts tended to sink during fermentation, and that beers brewed with such yeasts tended to be far more stable than those brewed with yeasts which rose to the top during fermentation. These top-fermenting beers were more prone to infection (by wild yeasts – especially during the summer months when harvesting of crops released vast numbers of airborne microbes), although the nature of the infection was then unknown. The beers brewed with bottom-fermenting yeasts tended to be clearer, slightly fizzy and more stable. Stability could be enhanced if the products were stored at low temperature in vaults or caves, thus enabling brewing to be carried out throughout the year. Such beers were the forerunners of our present day lager styles.
One of the most important results of monastic research was the recognition that hops contained components that were ideal for flavouring and preserving beer. As far as we know, hops were first used by brewing monks in the Hallertau region of Bavaria in 736AD and their use spread gradually throughout northern continental Europe, although they did not reach the British Isles until 1524 via Flemish settlers to Kent. The use of hops resulted in a totally different style of beer: these were much more bitter than any preceeding products, and this led to the inception of the 'bitters' that are still prevalent in the UK today. Technically, any product flavoured with the hop is referred to as beer (or bier), whilst products using other flavourings are defined as ales.
LOUIS PASTEUR (1822–1895)
Louis Pasteur (Figure 1.3) was born at Dole in 1822, the son of a tanner. He was appointed Professor of Chemistry at Lille in 1854 and soon became involved in alcoholic and lactic fermentations and the production of vinegar.
His research career spanned the years 1847–1895 and included fields as diverse as crystallography, infectious diseases (anthrax, gangrene and rabies) and diseases of silkworms. He began his studies on fermentation in 1856 when a Lille sugar-beet alcohol manufacturer asked for scientific advice. Studies on the doctrine of spontaneous generation began in 1859 and these led directly to the discovery of the reality of anaerobic life (1861) and the establishment of the fact that fermentations are caused by living organisms.
Research into the causes of wine infections commenced in 1863 and led directly to the laying down of the principles of pasteurisation, whereby bottled wine was rendered more stable by heating to around 55 °C and then allowing it to cool. A similar technique had already been invented by Scheele in 1782 for the sterilisation of vinegar, but Pasteur was actually able to explain the scientific principles behind the process. These extensive researches culminated in the publication of Etudes sur le Vin in 1866 and Etudes sur le Vinaigre in 1868. Neither work was considered seriously over here because of the inapplicability to British industrial processes and by the lack of any English translation.
The Franco–Prussian war of 1870–1871 and the subsequent defeat of and occupation of parts of France actually provided the stimulus for Pasteur's temporary obsession with beer. Being highly patriotic, he thought that by improving the quality of French beer he could 'get back at the Germans' by producing superior products which would gradually replace the hitherto more consistent and popular German beers from their European markets. French beer production at that time was wholly unscientific and it was pure chance that a wholesome batch would be produced. In 1871, Pasteur visited the laboratory of Prof. Emile Duclaux at Clermont-Ferrand and soon became associated with a small brewery at nearby Chamalieres. There he devised a new method of brewing (which he patented on 28 June 1871). The whole ethos of the new method was to avoid contact between beer and the atmosphere as far as possible, and hence to reduce the likelihood of contamination. According to Pasteur, beers brewed by his new method should be called 'Bières de la Revanche Nationale', or 'Revenge Beers'. The brewery at Chamalieres was very small and Pasteur felt the need to work at a far larger concern. Having no desire to visit a German brewery, he turned to England where he arrived in September 1871 with a small entourage. From his base at the Grosvenor Hotel in Victoria he visited a number of London breweries during his fortnight stay. The only surviving record of his visit is of 9 September 1871 when he toured the Whitbread Brewery in Chiswell Street. Although some major British breweries employed microscopes at this time, Whitbread & Co. did not, and during his investigations (he carried his own microscope) Pasteur found serious contaminations in the porter yeast and the ale yeast. The beer-finings were also found to be contaminated. As a result of a management meeting, fresh yeast was obtained from a nearby brewery and it was agreed that many of Pasteur's brewing tenets should be instigated. On revisiting the Chiswell Street brewery about one week later he found that a microscope had been purchased and new yeast management procedures adopted. Thus, the huge Whitbread tradition of scientific laboratory control of the brewing process emanates from Pasteur's visit.
On his return to France, Pasteur continued his interest in beer, being based at the Ecole Normale in Paris where he established a pilot brewery. Various ammendments and additions were made to his original patent and in 1876 his classic work, Etudes sur la Bière, was published. Fortunately this was translated into English three years later by Faulkener and Robb as Studies on Fermentation and this led to considerable reaction throughout the British Brewing Industry.
Pasteur's full-time obsession with beer (he did not like it himself) declined by the end of 1876 and he reverted to rather more medical matters. He paid a second visit to London in August 1881 where he represented France at the International Congress of Medicine. (There is no evidence to suggest that he visited any breweries on this occasion.) Although there is evidence to suggest that some of Pasteur's work was not entirely based on original ideas, there is no doubt that he was a major contributor to the science of brewing; indeed, the foundation of Jacobsen's Carlsberg Laboratory in Copenhagen was as a direct result of the Dane's admiration for Pasteur. For the last seven years of his life Pasteur was a member of the Laboratory Club (the forerunner of the Institute of Brewing).
ANTONJ VAN LEEWENHOEK (1632–1723)
Born in Delft, Anton van Leewenhoek was a cloth merchant and trained as a draper. His hobby was lens-grinding, and his inspiration was the English natural philosopher Robert Hooke, whose book Micrographia, published in 1665, contained details of small single-lens microscopes. Van Leewenhoek made the best lenses available at the time and his methods were a closely -guarded secret. In 1676 he published his classic drawings of 'animalcules' and communicated a paper on the same subject to The Royal Society in 1677. He was the first person to observe and describe yeasts, when he suspended beer samples in fine glass tubes and observed through his microscope. He thought that the irregular globules he detected (in fact, yeast) were related to and/or derived from starch grains obtained from wheat, oats or barley which were utilised in the manufacture of beer. There was a 'globulist theory' of matter at that time, which stated that 'living things were composed of small globules'. Some of van Leewenhoek's single-lens microscopes still exist (magnification of around x 300).
ROBERT BOYLE (1627–1691)
Boyle, the 'father of modern chemistry' was a pioneer of experimental method and was fully aware of the importance of fermentation. In his 1661 Essay on the Pathological Part of Physic he states: '... he that thoroughly understands the nature of ferment and fermentation, shall be much better able than he that ignores them, to give a fair account of diverse phenomena of several diseases ... which will perhaps be never properly understood without an insight into the doctrine of fermentations'. This statement predates by some two hundred years the work of Louis Pasteur ( 1822–1895).
(Continues...)
Excerpted from Brewing by Ian S. Hornsey. Copyright © 1999 The Royal Society of Chemistry. Excerpted by permission of The Royal Society of Chemistry.
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