Is there a definition of beer that can be used by a beer historian ?
Beyond the linguistic conventions and the multiple names that designate beer in one country or another, is Beer a generic beverage or is this lexical label simply used to aggregate a disparate set of fermented beverages?
If a beverage that we today call Beer" crosses the millennia and transcends the multitude of human cultures, how can we define it in order to compare its different technical formulas and tell what will then become its very long story.
The legal (or fiscal) definitions of beer depend on national administrations and traditions. They are motivated by commercial policies: the internal trade of each country and the import/export logic. What type of beer is allowed into the country? What type of beer is wanted to be sold abroad? They therefore vary from one country to another, from one continent to another. The beer professionals pointed out that this plethora of beer definitions made no mention of the quality of the product.
These definitions have no scientific basis. They are based on brewing technology as it stood at the dawn of the 20th century: beer = malt + hops + water. Malt and hops are the cornerstones of these definitions, ingredients made compulsory in varying proportions depending on each country. Even within this very restrictive technical framework, the national definitions differ.
The result of agreements between the beer industry and the tax authorities of each state, these definitions are not only useless for the historian and technologist, but also hinder historical research. In the past, endless debates have tried to settle a groundless question: were medieval cervoise or non-hopped English ale real beers? The "real" beer would have been born with the systematic addition of hops in its production.
The common dictionary definitions more or less mirror those of industrial beer. Most of them are tautological: " Beer = a drink that meets the criteria of what is called beer in such and such a language ". This leads either to very rigid definitions (beer = water + malted barley + hops) or to definitions so loose and elastic that they sometimes include every alcoholic beverages (beer, wine, mead, distilled alcohol).
The only solid ground is that of biochemistry, which describes the basic processes involved in beer making. It requires the isolation of the most fundamental mechanisms, regardless of historical techniques and their innumerable variants known throughout the world for 10 to 8 thousand years.
The inventory of the fundamental biochemical transformations at work in the brewing of beer provides us with the elements of a definition that stands the test of historical facts. It transcends the multitude of local brewing processes attested by ancient and modern documents. Equipped with a "universal" technical definition of beer, the historian can trace its presence in ancient testimonies of all kinds and compare the different versions of the brewing cycle implemented throughout human history.
Beer-Studies propose this définition.
BEER IS AN ALCOHOLIC BEVERAGE PRODUCED BY THE JOINT OR SEQUENTIAL ACTION ON STARCH OF AMYLOLYTIC ENZYMES AND GLYCOLYTIC ENZYMES.
This definition focuses on the raw material, a starchy paste, whatever its origin (cereals, tubers, starchy fruit seeds, starchy pith of some trees, etc). It defines the necessary biochemistry: saccharification of starch and alcoholic fermentation of sugars.In the brewing patterns used throughout the world, these two transformations may be simultaneous ( Asian/Amerindian tradition) or occur one after the other (European/African tradition). Note that this generic definition does not mention any ingredient other than starch. Flavourings, preservatives, sweeteners are adjuvants. They do not differentiate beer from wine or mead. They have varied a lot throughout the history of the beer brewing.
J.-P. Hébert proposed another synthetic formulation: beer is an alcoholic drink obtained by the transformation of starchy substances by enzymatic and microbiological means .
Beer-Studies underlines the amylolysis-glycolysis couple, whose intervention during brewing can be either consecutive (Western tradition) or simultaneous (Asian tradition). Nevertheless, these definitions are equivalent.
 Axel G. Kristiansen has listed in 2012 all these legislations (Europe, Canada, USA, Vietnam, South Africa, ...) published at that date. A compendium of heterogeneous definitions with only one thing in common, the mention of malt, hops and % alcohol. These fiscal definitions are based on a logic of taxation of beer and classification of fermented beverages. They are not concerned with quality criteria. Beer – is a definition possible ? Axel G. Kristiansen. 2012
 You can brew beer without hops or replace it with other plants. The list of herbs used in brewing through the ages is very long.
 Technologists did not wait for a definition of beer to study the biochemical mechanisms at work in amylolysis and alcoholic fermentation as early as the middle of the 19th century. About the implementation of the laboratory in breweries, see Brewers-engineers in a brewery lab
 Professor ENSIA, brewer-engineer specialising in tropical countries. J.-P. Hébert talks cautiously about the microbiological pathways, suspecting the discovery of alcoholic fermentation in a bacterial cell. The definition given by Beer-Studies derives from this questioning and came into being thanks to his author's insightful reviews and suggestions.