The Beer Brewing Process – From Barley to Glass

26.11.24

Ein lächelnder Brauer in einer Brauerei, trägt ein Jeanshemd und eine braune Schürze, hält ein Glas bernsteinfarbenes Bier vor glänzenden Braukesseln.

Beer is not only one of the world’s oldest beverages but also one of the most diverse, refined over thousands of years through a precise and complex process.

In this article, we provide a detailed and well-founded introduction to the beer brewing process. We explain the chemical and biological reactions involved and how each step significantly impacts the quality of the final product.

Ein Glas frisch gezapftes Bier mit cremigem Schaum, daneben Hopfendolden und Weizenähren, auf einer grauen, rustikalen Oberfläche.

The 4 Main Ingredients of Beer

The quality and harmony of the main ingredients are crucial to the final product. Each ingredient plays a specific role in the brewing process, influencing the flavour, aroma, and stability of the beer in various ways.

Ein Glas klares Wasser wird aus einem Krug auf einen Holztisch gegossen, mit grünem, unscharfem Hintergrund.

1. Water: The Chemical Foundation of Beer

Water, comprising about 90% of beer, significantly influences both the taste and the brewing process.

The mineral content of water—particularly calcium, magnesium, and sulphates—affects enzyme activity during mashing. For example, calcium enhances enzyme activity and improves beer clarity.

Modern breweries often employ water treatment to achieve the ideal composition and optimise the pH for the brewing process.

2. Malt: The Complex Sugar Source

Malt is not just a source of sugar; it also contributes to the beer’s colour and aroma through its roasting.

The degree of roasting determines the amount of fermentable sugars and non-fermentable components, which later define the beer’s body. Speciality malts like caramel or smoked malts can add unique flavours such as toffee or smokiness.

The enzymes in malt, such as amylases, are responsible for breaking down starch into sugars that are fermentable by yeast.

Hände lassen goldgelbes Malz in einen Sack rieseln, das für den Brauprozess verwendet wird.

Zwei Hände halten frische grüne Hopfendolden, die für die Bierherstellung verwendet werden.

3. Hops: Aroma and Natural Preservative

Hops contribute not only to bitterness but also to beer preservation, thanks to their antimicrobial properties.

Alpha acids in hops provide the characteristic bitterness, released through isomerisation during boiling. Different hop varieties introduce aromas of citrus, herbs, or flowers to the beer.

The timing and duration of hop additions play a decisive role in balancing bitterness and aroma.

4. Yeast: The Biochemistry of Fermentation

Yeast is responsible for converting sugars into alcohol and carbon dioxide through a biochemical process known as alcoholic fermentation.

Hundreds of yeast strains produce different esters and alcohols depending on temperature and oxygen levels. These by-products often add fruity or spicy notes to the beer.

Top-fermenting yeasts (Saccharomyces cerevisiae) and bottom-fermenting yeasts (Saccharomyces pastorianus) react differently to environmental temperatures, significantly influencing flavour development.

Ein Haufen trockener Bierhefe auf einem Holzbrett, im Hintergrund ein Messlöffel mit zusätzlicher Hefe.

The Brewing Process: Step by Step

Illustration des Bierbrauprozesses mit den Stationen Malzen, Maischen, Kochen, Kühlen, Fermentation, Filtern und Abfüllen.

The brewing process is a precise sequence of steps involving chemical and physical reactions.

Each step contributes to shaping the desired characteristics of the beer, from malt extraction to final bottling.

Malling: Opening the Malt Kernels Efficiently

Milling crushes the malt to release starch for enzymatic conversion. The grain size is critical: overly fine milling can clog the lauter tun, slowing filtration, while coarse milling reduces starch breakdown efficiency.
Mashing: Optimising Enzyme Activity

Mashing requires precise temperature control to activate specific enzymes.
Beta-amylases work at 60–65°C to produce fermentable sugars, while alpha-amylases at 68–72°C create dextrins that enhance body. Targeted temperature steps during mashing allow control over sweetness, body, and alcohol content.
Lautering: Efficient Separation of Wort and Spent Grains

Lautering separates the liquid wort from solid spent grains. Modern lauter systems use plate filters or centrifuges to accelerate the process and maximise yield. This step’s efficiency influences the fermentable sugar content and, subsequently, the beer’s alcohol level.
Boiling: Precise Hop Additions and Sterilisation

Boiling sterilises the wort, killing unwanted microorganisms.
Hop additions occur in stages: early for bitterness, late for aroma. Unwanted compounds like dimethyl sulphide (DMS), which imparts a cooked corn flavour, evaporate during this step.
Whirlpool and Cooling: Preventing Oxidation

The whirlpool process removes hop residues and coagulated proteins before the wort is rapidly cooled to fermentation temperature. Modern plate coolers bring the wort to the desired temperature in minutes, minimising oxidation.
Fermentation: The Science of Alcohol Production

Fermentation is biochemically complex, influenced by factors like temperature and oxygen availability.
Too fast or slow fermentation can result in unwanted by-products, such as fusel alcohols or acetaldehyde, which negatively impact aroma. Open fermentation is sometimes used to develop more complex flavours.
Maturation: Ageing and Micro-Oxidation

During maturation, flavours evolve, and carbon dioxide is naturally produced by yeast.
Storage conditions, including temperature and pressure, influence microbial processes in the beer. Some breweries use oak barrels for controlled micro-oxidation, adding complexity to the beer.
Filtration: Clarity Without Flavour Loss

Many breweries use modern crossflow or centrifugal filtration systems to clarify beer without impacting its flavour.
Unfiltered beers, offered by some breweries, often feature more complex flavour profiles.
Bottling: Advanced Techniques for Consistency

Bottling is performed under high pressure and oxygen-free conditions to prevent oxidation.
Modern bottling systems use nitrogen or CO2 flushing to minimise oxygen ingress.

Eine große Lagerhalle mit Reihen aus Holzfässern, die zur Reifung von Bier oder Wein genutzt werden, unter warmem, industriellem Licht.

Special Case: Non-Alcoholic Beer

Modern techniques like vacuum distillation or reverse osmosis remove alcohol after fermentation without compromising flavour.

Vacuum distillation removes alcohol under reduced pressure and low temperatures, preserving aromas.
Reverse osmosis filters out water and alcohol while retaining flavour compounds.

Non-alcoholic beers often contain residual sugar, shortening shelf life. To counter this, breweries use pasteurisation or other stabilisation methods to maintain quality.

Factors Influencing Beer’s Flavour and Colour

Several factors affect a beer’s final taste and colour. Alongside ingredients, chemical reactions during brewing play a key role in developing flavour and colour.

1. Colour: Chemical Reactions and Maillard Effect

The beer’s colour is largely influenced by the Maillard reaction, which occurs during malt roasting. This non-enzymatic browning generates hundreds of flavour compounds responsible for roasted and caramel notes.

2. Aroma: Esters, Phenols, and Hop Oils

Beer’s aroma is shaped by various chemical reactions. Esters produced during fermentation provide fruity notes, while phenols add spicy aromas. Different hop oils, such as myrcene and humulene, also contribute to the complex aroma profile.

Modern Brewing Equipment for the Perfect Process

The success of brewing depends not only on ingredients but also on technology. Modern brewing equipment optimises the brewing process, ensuring top quality in every batch.

Conclusion

The beer brewing process is an art grounded in precise craftsmanship and deep science. Every ingredient and step impacts the quality and aroma of the final product. Modern breweries use advanced technologies to optimise the process and ensure consistent quality.

Are you interested in professional brewing equipment or want to learn more about beer production?