Glossary of technical terms


Amylaceous plants

Cultivated and wild plant whose at least one organ contains a high proportion of raw starch: grain, achene, tuber, bulb, rhizome, or tissue. Stored in the form of granules, starch is an energy reserve. The plant produces starch during its vegetative cycle, and uses it for its reproductive and growing phases.

Humankind has systematically misappropriated these stocks of natural starch in order to make beer and bread, without compromising the reproduction of plants needed to feed.

The raw starch granules stored by plants must undergo several treatments before they can be used by the brewer. Heating or high acidity releases the starch chains enclosed inside the granules by a crystalline amylopectin coating (starch gelatinisation). Then the starch chains (macromolecules) should be split into simple sugars (glucose, maltose) by hydrolysis.


Class of enzymes specialized in the hydrolysis of starch (plant) or glycogen (animal). The amylases are classified as glycosylases (EC3.2). They are found in saliva, digestive juices, pancreas, sprouted grains, some plants, yeasts, molds, and bacteria.

The α-amylases produce reducing sugars, little or non-fermentable (dextrins). The β-amylases, so-called saccharifying, produce fermentable simple sugars (maltose, glucose). The α-amylases are found in all organs and tissues, β-amylases almost exclusively among higher plants.


Breakdown of a starch macromolecule (polysaccharide) into sugars by the action of enzymes or an acid which cut (-lysis) the α- and β- chemical linkages between the monosaccharides.

Amylolytic (power)

Ability to hydrolyze starch owned by some microorganisms and fungi, with the action of enzymes from the class of amylases, in liquid medium. See Ferment (amylolytic).

Amylolytic (ferment)

See Ferment (amylolytic).

Amylolytic (plant)

Ability to hydrolyze starch owned by certain parts of plants (root, stem), with the chemical action of amylases fixed in their tissue.


Percentage of fermentable sugars converted into ethanol by yeast during the fermentation of the beer wort.


Beer is among the oldest fermented alcoholic beverages, along with wine and mead. Beer is especially the most widespread in the globe for thousands of years, on the four inhabited continents (Africa, Asia, Europe, America). Beer has played a vital role in the economy of Neolithic societies, in the emergence of the first city-states and primitive kingdoms, finally when the ancient empires were raising. Its importance has been neglected because historians have hardly detected its presence and influence under multiple names and faces borrowed by beer over the centuries, in so many different cultural areas. Without no technical definition of what is a beer, this fermented beverage is too often confused with the wine.

The beer meets a technical definition. Beer is a beverage produced by the alcoholic fermentation of sugars from starch. The starch sources are multifarious. They include every cereals (rice, millet, maize, sorghum, barley, wheat, rye, ...), tubers and rhizomes (cassava, yam, taro, sweet potato, potatoes), starchy fruits (plantain, carob, chestnut), and even the marrow of some palms (sago). The technical definition of beer includes all types of beer known since the beginning of the Brewery 8,000 years ago. The industrial or craft beer, made from barley or wheat, is but a small part of the vast universe and global history of Beer.

Beer technical definition

The technical definition of the beer differs from its legal or tax definitions varying across countries, national laws, and historical periods. The technical definition is based solely on the biochemical mechanisms that convert starch into beer. They refer to the saccharification of starch and the alcoholic fermentation.

This technical definition pulls the rug out under the cultural, linguistic, historical and legal arguments. All argue for relativism and the impossibility of achieving a generic definition of beer in the world and throughout history. Without a technical definition of beer, the historian does not know how to compare modern beer with medieval or ancient beers, the modern industrial beer with the traditional beers from around the world.

Beers (traditionnal)

Beer amateurs are largely unaware that peoples in the world still brew and drink some kinds of non industrial beers, in Asia, Africa or South America. These beers are not vestiges of prehistory. These are not primitive beers. Some, like sake or jiu are just as sophisticated than a Trappist beer. We call them "traditional beers", to differentiate them from the industrial beer or even the home brewed beers. In fact, the beer coming from vats of industrial or craft breweries is a modern variant of the traditional beers. Every beers in the world originated a common technical core, and belong to the same general beer story. All are changing at their own pace. The indigenous beers still exist and evolve in the modern world.

These traditional ales are found throughout the world, brewed by peoples and human communities who do not live according to the manners and customs of so-called post-modern societies. How designate them : native beers? Ethnic beers? Indigenous beers? Local beers? Ales? Their variety is almost endless, their flavors and aromas not at all standardized.


Set of production techniques, economic organizations and social rules that are intended to give beer, according to our definition of this beverage. The Brewery, in this broader sense, appeared 8000 years ago. Beer was born with the collective management of the starch resources, and the socialized manners of drinking fermented beverages. The brewery, in its current and narrow meaning (beer factory, beer pub), represents, with regard to the history of the brewery, a very recent episode (barely 200 years) linked to the industrial production of beer.

Brewing Bassin

A geographical and protohistorical area characterized by a similar development of the brewing techniques (among the 6 Brewing Pathways), the economic management of the Brewery, and the social role of the Beer. The planet is divided into Brewing bassins or Brewing historical zones. These basins roughly coincide with the major protohistoric cultural areas of the world, shaped during a period spanning from 8000 to 3000 BCE.

The geographic boundaries of one Brewing Basin evolved over time. Twenty Brewing Basins in the world have been counted at the beginnings of the Brewery. Some neighboring basins merged with time and movement of peoples (for example, the ancient "Near East basin" merged with the Central Asian basin), others have instead been divided (Tibeto-Burman Brewing basin separated from the Ganges Brewing basin). Drawing the spatio-temporal boundaries of the Brewing basins is a complex issue. Especially since the industrial brewery has spread across the world, eliminating or marginalizing the indigenous brewing customs, sometimes erasing their ancient traces.

Brewing (pathways)
(6 pathways or methods in all)

Process Implemented to saccharify the starch. It characterizes a brewing method. There are 6 brewing pathways known to date and implemented in one region or another on the planet-beer :

1 - Insalivation (salivary ptyaline = amylase)
2 - Amylolytic ferment (mold, bacteria)
3 - Malting (sprouted grains)
4 - Amylolytic plants (amylases fixed on plants)
5 - Over-ripening (hydrolysis speeded by heat and water)
6 - Acid hydrolysis (chemical acidity of the medium)

The 6 Brewing Pathways can be complementary, that is to say conjointly employed at the same time in the same country, but in different social and cultural contexts.

A brewing method characterizes a type of beer, but not a region, a historical period or a particular cultural area. For the same historical and geographical context, the Brewery has often used several methods simultaneously, sometimes all six.

Combined (fermented beverage)

In the Neolithic time, one mixes every fermentable natural products that plants and bees (and some wasps) can offer : fruits, honey, crushed grains, roots, saps, juices, sweet exudates. These first fermented combinations are both wines, mead and beer, indiscriminately. Some chemical traces of these primitive fermented beverages were discovered and analyzed on sites from the Neolithic period. These fermented combinations are the primitive ancestors of beer stricto sensu (Beer technical definition), but should not be confused with it. Beer is starch based only, and subjected to a specific process of saccharification. Sugar, fruit or honey can be added during or after fermentation. But these optional additions of sugary matter do not affect the brewing itself.

Stricto-sensu beer came into being when starch-based fermented beverages were differentiated and separated from the primitive base of combined or mixed fermented drinks. This long and complex evolution has occurred at different times in different places of the world, but it has always taken place.


A polymer of D-glucose intermediate between starch and maltose. Obtained by hydrolysis of starch with α-amylase, heat or acid. The dextrins give less viscous solutions than starch. They are soluble in water, insoluble in alcohol. The maltodextrins from malting have a very low molecular weight which makes them fermentable.

Drinking straw

Traditional beers have little or no filtration. The drinking straw is a tube with a narrow hole at one end designed to sip the beverage where grains or grain residues are floating in. It has been in general use since ancient times on all continents. The oldest beer drinking straws were found in the Near East in the 2nd millennium BC. They are attested in Egypt, Asia, Africa and South America. They cover two distinct uses. Some beer straws are luxury items, found in palaces and obviously reserved for privileged people as personal utensils. They are made of more or less precious metal, copper, tin or silver. They serve an individualised drinking manner. On the other hand, other beer straws are long flexible reed stems used for collective drinking of the beer. Plunged into a beer jar, they allow a group gathered around to sip the same beer together. This collective way of drinking beer is characteristic of village communities in Asia, Africa and South America. Curiously, the use of beer straws is not attested in Europe during the Bronze or Iron Ages. Collective beer drinking is manifested by the circulation of drinking cups or horns between the drinkers themselves grouped around large beer vats. This way of drinking beer practised by the Celts, Germans or Scandinavians corresponds to groups of warriors or peasant-warriors loyal to a war chief. We do not know the drinking habits of the poorest categories, let alone slaves in Europe before the Middle Ages, if they were allowed to drink beer at all.

Ferment (amylolytic)

An amylolytic ferment has the power to saccharifying starch through the amylases of certain molds. This is the brewing path (method) no 2.

It is obtained by cultivating mushrooms on a medium of cooked starch (patties, dumplings). Once dried, the ferment will keep a year or more. Once rehydrated, the amylases of mushrooms hydrolyze any porridge of meal from grains or roots (cassava, taro, yam, sweet potato, etc..).

Fermentation (bottom fermentation)

Fermentation with so-called "bottom fermenting" yeasts. The yeasts ferment at low temperatures (10°-15°C) for a longer period of time than with top fermentation. This method requires refrigeration of the wort during fermentation, a biochemical reaction that releases heat. The yeast strains are derived from Saccharomyces uvarum, itself derived from S. Carlsbergensis isolated by Hansen in 1883. Bottom fermentation was already practised by Czech and Bavarian brewers in the second half of the 19th century, with natural (cellars) or controlled (stored ice) refrigeration, soon replaced by artificial refrigeration (Linde, 1873). During the 20th century, bottom fermentation gave birth to types of beer that upset the image of traditional beers. Lager, Pils, Bavarian and Alsatian beers are drunk fresh, sparkling, frothy, ultra-filtered.

In just one century, bottom-fermented beers have eclipsed the majority of traditional beers in Europe and the United States. In other countries of the world, this type of beer came with the colonial enterprises. In Asia, Africa and Latin America, most industrial breweries were created on the European model of bottom-fermenting and beer being served cold and sparkling. Lager became the ultra-dominant type of beer, trumping all other traditional beers in the world.

Fermentation (top fermentation)

La fermentation haute est associée en Europe aux bières traditionnelles brassées selon la méthode du maltage (méthode n° 2). Les levures remontent à la surface du moût, la température de fermentation oscille entre 15-24 °C, idéalement 18-21 °C. La fermentation primaire est plus rapide (4-5 jours) comparée à la fermentation basse. Les levures de fermentation haute dégagent des principes aromatiques (esters) qui caractérisent des bières plus complexes et plus diversifiées. Ces qualités organoleptiques ont été mises à profit par les brasseries de fermentation haute au 20ème siècle. La domination des bières de fermentation basse (lager, pils) a poussé les brasseurs de fermentation haute vers le créneau des bières de dégustation : bières d'abbaye, bière de saison, de noël, double ou tripple (Belgique), stout, porter, India Pale Ale (Irelande, Grande Bretagne), Kölsch, Altbier, Weizenbier (Allemagne), bière de garde ou de Mars (France), etc.

The improvement of yeast selection techniques has made this high vs. low fermentation classification obsolete. Biotechnology is able to isolate and reproduce mixed yeasts that combine the properties and advantages of both "high" and "low" strains..

Traditional African or Amerindian beers are often wrongly described as "top fermented" beers. The yeast and bacterial flora that ensure fermentation are too complex and variable to be reduced to the work of Saccharomyces. Other yeasts are involved. The concept of "spontaneous fermentation" would be more accurate.

Fermentation (spontaneous ferm.)

Spontaneous fermentation is characterised by the absence of deliberate inoculation of the wort with yeast (top, bottom or mixed). Lambics from the Brussels region are the best example of this. During the cooling phase after boiling, the wort is spread out in a wide, shallow tank so that airborne yeasts can seed it. Although specific to lambic brewing, the composition of the wort (1/2 wheat, 1/2 barley malt) is not critical. On the other hand, the use of over-aged hops (aged and oxidised) favours the growth of certain micro-organisms which would be prevented by too high a concentration of isohumulone and lupulone, two antibacterial acids.

Lambics and gueuzes (a blend of young and old lambics) stand out from classic industrial beers because of their acidity, aromatic richness and slight astringency. These beers offer new organoleptic experiences, the rediscovery of flavours and aromas forgotten by consumers of industrial beverages and beers.

Archaeology often associates primitive beers with spontaneous fermentation, a connection that is not always accurate. Traditional brewing in Asia, Africa or America knows how to isolate, preserve and reproduce beer ferments which are reused to seed subsequent brews. This very old technique aims to control fermentation, as opposed to spontaneous fermentation. Another technique, that of amylolytic ferments, completely controls the seeding of the brews. Spontaneous fermentation" is more of a modern re-invention, a reaction to the excesses of industrial pasteusisation, which has forgotten that fermentations are also sources of very complex and pleasant orgnoleptic compounds, not to mention the amino acids and vitamins that are essential to human life.


With the grain malting method, filtration takes place at two key points: 1) to separate the wort from the spent grain after the infusion or decoction phase. 2) between wort boiling and fermentation to remove coagulated proteins and hop residues. In the brewing methods with insalivation or use of amylolytic herbs, two filtrations are also performed at the same time, but without the use of hops. In the other three brewing methods, a single final filtration separates the solids from the fermented liquid, the beer. The Asian brewing method differs radically from Western brewing. Saccharification of the grains and fermentation take place in a semi-solid phase, without the need for filtration. The final filtration removes the solid residues after the water has been added. This implies drinking, or rather sucking on these beers with a drinking-straw..

In the course of the history of beer, the techniques and materials used for filtering are very diverse. Pierced pottery found by archaeologists, fabrics, vegetable or animal filters (powdered shells, pierced horns). Industrial brewing has improved these filters without revolutionising ancient techniques: filters with cotton plates, diatomaceous earth powder, double-bottomed brewing tanks, etc. Simple decanting is also a method of filtration. Some African brewing techniques accelerate decanting by adding mucilaginous plants (e.g. cooking the wort with okra in the brewing of dolo in Mali).


Metabolism of yeast and bacteria that converts simple sugars (glucose) into pyruvate. The latter, in lack of oxygen (anaerobic), is transformed into ethanol (fermentation) or lactate (lactic acid fermentation).


Chemical reaction of a complex compound with water, in this case a chain of saccharides (starch), and catalyzed by an acid or an enzyme. The hydrolysis plays a vital role in the metabolism of plants and animals. The catalytic action of specific enzymes allows carbohydrates, proteins, fats, and oils to be hydrolysed into soluble molecules.

Hydrolysis (acidic)

Hydrolysis of starch in water with a strong acid acting as a catalyst. In brewing, the acidity of the mash accelerates starch saccharification. This acidity is enhanced by the presence of weak acids, for instance lactic acid. The brewing method by acid Hydrolysis favors this way of saccharifying starch. This is the brewing path (method) no 6.


Method of starch saccharification by impregnating a cooked starch paste with saliva. The salivary ptyalin is a powerful enzyme for saccharification. This is the Brewing Pthway (method) no 1.


Infusion of the saccharified mass with water at 60°-75° C, optimal range of temperature for the α and β amylases activity. These enzymes are found in every sprouted grains and almost all starchy storage organs of the plants (tuber, pith, bulbs, root).


Seeds of cereal, sprouted and dried. According to the method and timing chosen to dry the sprouted grains (green malt), the maltster get different qualities of malt. With germinated barley, he gets various kinds of malt more or less colored (pale, golden, or amber malt), more or less browned or roasted (brown malt, "chocolate" malt). The malts from sorghum, maize or millet give to beer manifold colors according to the variety of each grains species (white, yellow, red, purple, brown). The malt can be stored a year and more, in a dry place. Deprived of its embryo, the malt grain can no longer germinate. That allows to store the malt longer, but forbids to use it as a seed. Therefore, the decision of malting a part of the grain provisions has always been a strategic arbitration for the traditional societies, whose food survival depended on their granaries and the annual sowings.


A method of starch saccharification using the germination of cereal grains. All cereals can germinate and therefore be malted, except the rice grain because its embryo is torn out of the seed when harvesting. Germination is brought about by soaking grains. The embryo generates itself the amylases that convert (hydrolysis) into sugars the starch enclosed in the endosperm of each grain. After a few days, the germination is stopped by drying the sprouted grain. By stopping the germination just in time, the brewer gets fermentable sugars (starch already saccharified), but also a grain filled with amylases. A simple soaking in water at the right temperature (60-70 ° C) is sufficient to activate these enzymes that complete the conversion of the remaining starch in malt, and are able to saccharify the starch added with raw (unmalted) grains. This is the brewing path (method) no 2.

Mixed (fermented beverage)

In its definition, beer is a fermented drink made of starch. In practice, sugars from fruits, honey, saccharified saps, sugary exudates or industrial glucose can be added to beer (to the beer wort rather). Hence, it is refered to as a sweetened beer.


Brewing method causing the breakdown of the starch from fruits (plantain) and tubers (cassava, yam) by heat and addition of water. The action of the natural amylases of these plants is accelerated, and their starch is quickly saccharified. As with the malting (germination of cereal grains), the brewer simply initiates and controls a natural biochemical process. This brewing process is the Brewing Pathway (method) no 5.


Beer was invented independently in several regions of the world, giving rise to different brewing regions or "Brewing basins". Beer becomes the most widespread fermented beverage among the peoples since mankind was growing or gathering many starchy plants.

Plant (amylolytic)

Plants whose roots or leaves are able of hydrolysing the starch thanks to amylases (enzymes) contained in their tissues. They have been identified in Africa where they are used to brew beer, but other species exist elsewhere in the world. This brewing process is the Brewing Pathway (method) no 4.

Ratio grain/beer

This ratio defines the proportion of grain used to brew and the final volume of beer obtained. It is an indirect measure of the density (% alcohol) of the beer. It is not an exact indicator. The alcoholic fermentation is more or less complete (attenuation). Also the conversion of starch into fermentable sugars. The percentage of alcohol in a beer depends on many factors, starting with the nature of the grain (malt, raw grain, barley, wheat, oats, maize, rice, etc.)..

The calculation and control of brewing with a grain/beer ratio is not a modern invention. This ratio was calculated as early as the 3rd millennium in Mesopotamia and Egypt to define different qualities of beer, generally 3 kinds: strong, standard, weak. This ratio was implemented by Buddhist communities in northern China in the 8th-10th centuries, to control the categories of rice beer allocated to various social categories of people. In ancient times, the quality of beer is directly measured by the amount of grain used to brew it. In deeply hierarchical societies, this ratio played a crucial socio-economic role. In medieval Europe, it was revived in monastic communities, a paradoxical use of 3 kinds of beer for monks proclaiming their equal status. In modern times, European states restored a classification of beers according to their density, this time for fiscal reasons. Soon to be imitated by other governments around the world and international customs regulations.

Saccharification (starch)

A process converting starch into sugars. The crude starch is not fermentable. It can not be assimilated by the yeast metabolism responsible for the alcoholic fermentation. The starch macromolecule has too high molecular weight to cross the membrane of the yeast cell. Moreover, it is more insoluble. The brewer must first split the starch macromolecule into simple molecules of soluble sugars (Hydrolysis). These sugars (glucose, maltose), assimilated by the yeast cell, are then metabolized by glycolysis.

The saccharification of the starch is the technical hallmark of the brewing. The mead and wine require no prior saccharification. There are 6 ways of saccharifying starch (6 Brewing Pathways). All these methods have been and are still used in the world, sometimes side by side in the same country or area, to brew different kinds of beer.

Schema (for brewing)

Specific sequence of technical operations leading from the raw starch to the finished beer. Their diversity is very high. The technical shemas used to brew traditional ales are often more complex than the industrial brewing patterns oriented towards the reproduction of one identical beer.

Spent grains

Whatever the method, brewing leaves residues : the spent grains, which should not be confused with the sediments of the fermentation (dregs of beer). The grains consist of husks, fibers, and solid plant residues other than starch.

Rich in cellulose and proteins, the spent grains are from the beginning of the brewery recycled as feed for poultry or small livestock. They complement the fodder and grains given to them at the rate of 10% to 20% of their total volume, not more because they cause fermentation. The wet spent grains have the same volume as the grain brewed when used by the brewing method of malting (malt + optional raw grains). The spent grains can be dried to preserve them. The recycling of spent grains has always put the brewery in close economic relationship with breeding in traditional societies.


A complex carbohydrates serving as energy supply to plants. The starch is found in almost all their organs. It is especially abundant in the organs related to reproduction (seeds, fruits, tubers) and plant nutrition (roots, rhizomes, stems, spinal trunk of some tree species).

Starch is a polysaccharide. It consists of very long branched chains of D-glucose. They are of two types: amylose (up to 1000 glucose molecules), and amylopectin very long and branched (from 10,000 to 100,000 molecules of glucose).

Starch gelatinisation

Released in the water, the starch contained in the starch granules of plants is soluble and crystalline. Under the effect of heat, it becomes insoluble and has the appearance of a thick starch. This is the gelatinisation (or pasting) of starch. Its molecular macrostructures absorb water (visible swelling of the starch) and become amorphous (transparent viscous paste). Gelatinization depends on the origin of the starch (cereal, tuber, ...), temperature, acidity, the presence of salts, fats and proteins in solution.

This transformation of the raw starch is a vital step in brewing technology. It releases the long chains of amylose and amylopectin, which can then be cut into simple fermentable sugars (saccharification).


Technical name given to the sweet juice obtained by pressing or a simple extraction of the mass of saccharified starch. This step is required in the manufacturing processes associated with the brewing pathways no. 1, no. 2, and no 4. saccharification and fermentation succeed each other in two distinct phases. First get a sweet liquid (wort) is required to start the alcoholic fermentation. In the other brewing pathways, the alcoholic fermentation operates directly within the starchy mass, that is simultaneously undergoing its saccharification. In that case, passing by a liquid phase (beerwort) is no longer required. Beer is got by extracting the juice from the fermented slurry.


Unicellular fungus whose metabolism converts sugars into alcohol, CO2 and heat, in anaerobic conditions. Many strains of yeast have been and are still used to manufacture beer. In modern times, the main strain is Saccharomyces cerevisiae. For the purposes of industrial brewery, it became the main yeast strain in brewery. But other strains were and are still used to make beer worlwide, especially to brew traditional beers : Saccharomyces delbrueckii, S. pastorianus, S. pombe, S. rouxii, S. sake, S. shaoshing, S. uvarum, etc.. (Species Fungorum).

Yeast (pure yeast)

In 1883, Emil Christian Hansen propagated a unique strain of yeast isolated from a population of Saccharomyces cerevisiae, which he named Saccharomyces Carlsbergensis in honour of the Calrsberg Laboratories for which he worked between 1879 and 1909. Hansen succeeded in controlling the reproduction of this strain in a sugar solution, without it mixing with other yeasts, thanks to an apparatus and a method of his own invention, albeit inspired by the brewers' yeast eggs and Pasteur's laboratory apparatus. This pure strain of yeast, isolated for its behaviour during the fermentation of the beer wort, will be the origin of all bottom-fermenting yeasts used by European brewers first (Carlsberg at first), then American. Now these brewers have complete control over the single, pure strain of yeast they use, which they can propagate at will using the Hansen process. This was a decisive kick-off for the development of lager and pilsner beers, with artificial refrigeration and plate filters.

Shortly afterwards, laboratories specialised in the production and selection of pure yeast strains for small and medium-sized breweries that did not have the means or the skills to equip a laboratory. The bakery sector soon became a loyal customer in Europe, demanding pure yeasts adapted to the needs of industrial bread-making. And finally the wine-making sector.


01/04/2013  Christian Berger