The Theory and Practice of Brewing

In Short

This book provides a rigorous, analytical approach to the art of brewing malt liquors, treating beer as a form of "barley wine." By moving beyond traditional "vague maxims" and secret recipes, it establishes fixed, temperature-based principles for every stage of the process—from malting and mashing to boiling and fermentation. It has endured as a primary historical document because it represents an early, sophisticated attempt to apply the scientific method to a common craft, documenting the technical transition toward the precision-based brewing standards we recognize today.

The Story

The narrative of this work is the evolution of brewing from an intuitive, tradition-bound craft into a measurable science. It begins by establishing the fundamental elements of nature—fire, air, water, and earth—as the primary actors in the transformation of grain into drink. The author frames the brewer as a practitioner of chemistry, arguing that heat is the "chief cause and principle of almost every change in bodies." This philosophical opening sets the stage for a systematic breakdown of the brewing process, moving from the microscopic properties of malt to the macro-level logistics of a commercial brewhouse.

As the text progresses, the reader is taken through the essential stages of production. The author explains the nature of barley, the critical importance of proper malting, and the chemical role of hops as both a preservative and a flavor agent. The core of the argument rests on the use of the thermometer to control the "extracting" of malt. By calculating the precise degrees of heat required for different strengths of ale and porter, the brewer can standardize results that were previously left to the whims of the season or the brewer’s imperfect sense of touch.

The arc of the book reaches its zenith when the author introduces elaborate tables of data, designed to guide the reader in adjusting their process for seasonal temperature fluctuations. He provides formulas for calculating the height of worts in the copper, the required volumes of water, and the necessary fermentation temperatures. He explicitly rejects the "prejudice" of secret or mystical methods, insisting that the "rational brewer" must plan every step in advance to ensure transparency, strength, and soundness in the final product.

In the final sections, the author addresses the practicalities of the brewhouse, from the arrangement of utensils to the management of fermentation. He concludes by reconciling his "new" theoretical approach with established practices, showing that successful traditional methods were always secretly obeying these laws of chemistry. He emphasizes that the "birth-place" of a beer matters far less than the scientific rigor of its production. By the end, the work has successfully transformed the image of the brewer from a laborer following a rote tradition into an informed professional capable of manipulating nature’s elements to create consistent, quality beverages.

How It Unfolds

The foundation of natural philosophy The book opens with a theoretical examination of fire and heat, establishing their role as the primary agents of change in all brewing processes. It asserts that the senses are unreliable judges, necessitating the use of the thermometer to accurately measure the behavior of water, wort, and grain.

The anatomy of malt The focus shifts to the biology of barley, explaining how malting alters the grain's oils and salts through controlled heat. The author categorizes malt by its drying temperature, establishing a direct correlation between the heat of the kiln and the final character of the beer.

The mechanics of extraction Detailed instructions follow on how to manage mashing and boiling using specific, calculated temperatures. The author provides complex tables to help brewers adjust their process based on the ambient air temperature, ensuring that the "extracts" remain consistent regardless of the season.

The precision of the copper The book delves into the technical logistics of the brewhouse, including the exact gauging of copper vessels. It explains how to calculate the precise "lengths" of worts to reach the desired strength, removing the ambiguity of guesswork in large-scale production.

The reconciliation of practice and theory The final chapters synthesize the technical data, comparing the author’s calculated methods against traditional brewing signs. By validating the old ways through the lens of new science, the text provides a comprehensive manual for the rational management of a commercial brewery.

The People

The book is driven by the voice of Michael Combrune, a dedicated practitioner who views himself as a pioneer of technical accuracy. He is a man of the Enlightenment, deeply respectful of the "counsel" and "zeal" of figures like Doctor Peter Shaw, the Royal Physician to whom he dedicates the work. Combrune is not a revolutionary looking to destroy tradition, but an improver who believes that "rational" methods will elevate the brewer’s craft to an art form. He is constantly fighting against two enemies: the "vague traditional maxims" that lead to inconsistent beer and the "prejudice" of those who cling to old, unscientific habits.

While the author acts as the primary instructor, his work is influenced by the great chemist Herman Boerhaave, whose theories on "menstruums" or solvents form the backbone of Combrune's understanding of how water extracts flavor from malt. Combrune treats the brewer as the central figure of the narrative—a person who must be observant, educated, and disciplined. He contrasts this ideal brewer with the "untaught" or negligent practitioner who leaves the quality of their work to chance. Through these pages, Combrune transforms the reader into a peer, inviting them to abandon superstition in favor of the thermometer and the scale, ultimately seeking the "satisfaction" of understanding the why behind the how.

In Its Own Voice

"The senses are very inadequate judges of it; the eye may be deceived, and suppose no fire in a bar of iron, because it does not appear red, though at the same time it may contain enough to generate pain."

This serves as a warning on why the author insists that brewers must abandon reliance on touch or sight and instead adopt the objective measurement of the thermometer.

"In this sense beers and ales may be called, and really are, barley wines."

This sentence defines the author’s conceptual framework, placing ale and beer within the noble, scientific category of fermented fruit juices.

"England, says Boerhaave, on this account, is remarkably happy: her fruits are capable of producing a great variety of wines, equal in goodness to many imported, were not our tastes but too often subservient, not to reason, but to custom and prejudice."

This quote highlights the author’s frustration with the public's preference for foreign imports over home-produced, scientifically-brewed ales.

What It's Really About

At its core, this book is an argument for the superiority of science over tradition. It posits that brewing is not a mystical art but a branch of chemistry, specifically the study of vegetable fermentation. The fundamental theme is the pursuit of "pellucidity" (clarity) and "soundness" (stability), which the author argues can only be achieved through a precise control of heat and air. The work challenges the notion that quality is a result of luck or local geography, insisting instead that any brewer, anywhere, can produce a superior product if they follow the objective laws of nature. It is a document of its era, reflecting a broader cultural shift toward rationalism and the belief that the material world can be fully understood and controlled.

Why Read It Today

Readers will find this book fascinating if they enjoy the history of science or the technical evolution of craft. It feels like stepping into an 18th-century lab; it is dense with mathematical tables, cooling charts, and chemical definitions that reveal how early industrial brewers thought about their work. You should be prepared for the specialized, somewhat archaic language of the mid-1700s, which can be dense and occasionally repetitive.

It is not a "how-to" book for a modern home-brewer looking for a quick recipe; rather, it is a demanding intellectual history. What stays with you is the author's relentless insistence on precision and his profound, almost poetic respect for the hidden properties of grain and water. It captures a moment when the human hand finally reached for the thermometer to master the unpredictable world of fermentation. For those interested in the transition from "art" to "industry," this book provides a rare, detailed look at the intellectual machinery of that change. It is a work of warmth and deep, practical pride, written by someone who truly believed that better beer was a matter of better understanding.