By Eleonora Curcio and Lorenzo Lodori

Introduction

In this article, we will explore the main steps and techniques used in beer production. The six steps involved in creating a bottle of beer include malting, grinding, mashing, boiling, fermentation & bottling. However, the process is much more complex than that, so let’s go on a deep dive into beer production techniques!

1. Malting: Transforming Barley (or wheat, rye, corn, …) into Liquid

Malting is the key of the beer production process, as it is here that the  essential enzymes for the subsequent mashing phase are activated. This process  has ancient roots, but thanks to scientific developments it is today a highly controlled and refined process.

The Malting Process

Malting begins with the selection of barley, the fundamental raw material for the production of beer. The barley is moistened and left to germinate under controlled conditions of temperature and humidity. This awakens the enzymatic process within the grain, activating the amylolytic and proteolytic enzymes necessary for the subsequent mashing phase.

After germination, the barley is dried in special ovens, to block the germination process and stabilize the newly formed enzymes. The temperature and duration of drying determine the final characteristics of the malt, influencing the colour, flavor and properties of the final product.

Process Control and Innovation

Thanks to the scientific studies conducted in the sector, the malting process is extremely controlled and monitored today. Parameters such as temperature, humidity, duration of the various phases are carefully regulated to obtain malts with optimal performance.

Additionally, the brewing industry has adopted technological innovations to improve the efficiency and sustainability of malting. For example, drying systems with lower energy consumption and “green” malts obtained with low environmental impact processes have been developed.

Malt: The heart of beer

Barley malt is the heart of beer, providing the fermentable sugars, enzymes and flavor precursors essential to achieving the desired sensory profile. Today’s breweries can count on malts of excellent quality and performance, allowing them to create unique and inimitable beers.

2. Grinding

During the malt milling phase, the grains are broken into smaller fragments to increase the surface area in contact with the water. This step can be performed both, dry and wet. Dry milling involves the malt kernels being crushed without the addition of water, while wet milling involves the use of water to aid the process. The reduction in the size of the malt fragments favors the action of the enzymes during the next phase, called mashing. The enzymes present in malt are crucial for the conversion of starches into fermentable sugars. Therefore, a greater contact surface of the malt grains with water thanks to grinding optimizes the effectiveness of this enzymatic process, contributing to the production of sugars necessary for fermentation.

In brewing, the skin of the grain, or bran, plays an important role in the filtration of the wort, which is the sweet liquid obtained from the mashing of grains and which will later be fermented to produce beer. The bran, being fibrous, helps to form a filtering bed that allows the wort to pass through the milled grain during lautering, the process of washing the grain to extract remaining sugars. Mentioning the importance of the bran during the brewing process is crucial to ensure good extraction efficiency and effective filtration. Here are some key points to consider:

1. Extraction Efficiency: The bran contains fibers that can help maintain a stable filtering bed, allowing for better separation of the wort from the solids.
2. Filtration: The presence of intact bran is essential for creating an effective filtering bed during lautering. Without it, the wort could be cloudy and contain unwanted particles that could affect the final quality of the beer.
3. Separating and Readding the Bran: Some breweries choose to separate the bran from the milled grains before mashing and then add it back later. This process can be laborious and requires specific equipment, but it can be useful for better controlling the density of the filtering bed and the extraction of sugars.
4. Milling with the Bran: Milling the grains with the bran is a common practice in many breweries. This approach simplifies the mashing process and maintains the natural fibers that help in filtration. However, it can be more difficult to control the extraction of sugars and the consistency of the filtering bed.
5. Practical Considerations: Separating the bran can be an additional step that requires time and resources, but it can offer advantages in terms of process control and the quality of the final product.

However, many breweries, especially smaller or craft breweries, prefer to keep the bran during mashing to simplify the process and reduce costs. In conclusion, the decision to keep the bran during mashing or to separate it and then add it back later depends on the brewer’s preferences, the available equipment, and the quality goals for the finished beer. Both approaches have their advantages and disadvantages and can influence the brewing process and the quality of the beer produced.

3. Mashing

The Mashing: From Grinding to the Creation of the wort

Mashing is one of the crucial stages in the brewing process, as this is where fermentable sugars are extracted from the malt for subsequent fermentation. This phase requires precise control of the parameters to obtain the optimal must.

The Infusion and Decoction

Once ground, the malt is immersed in warm water, typically not exceeding 40-50 degrees Celsius, in special mashing vessels. This is where the key phase occurs, where the malt’s amylolytic and proteolytic enzymes break down starch and proteins, releasing fermentable sugars and other essential beer components.

There are two main mashing techniques: infusion and decoction. In the infusion method, the malt is kept at defined temperatures to optimize the efficiency of individual enzymes over specified periods. Decoction, although rarely used today, involves extracting a part of the mash, bringing it to a boil, and then reintroducing it into the vessel to heat the entire mash. This method is mainly used when beers with a very low remaining sugar content after fermentation are anticipated.

These techniques differ in the temperature profiles applied, which influence the composition of the extracted wort in terms of sugars, amino acid nitrogen, and beta-glucans.

Process Control and Innovations

Today, mashing is a highly controlled and monitored process. Key parameters such as temperatures, run times and malt/water ratio are carefully adjusted to obtain the wort with the desired characteristics.

Additionally, technological innovations have been developed to improve mashing efficiency. For example, the use of plate heaters or steam injection allows you to apply more precise and reproducible thermal profiles, promoting better extraction of ingredients.

The Wort

The wort obtained from mashing contains all the nutrients essential for yeast activity during fermentation. Thanks to continuous improvements in mashing techniques, modern breweries can rely on high-quality worts and optimal characteristics for the production of beers with unique sensory profiles.

4. Boiling of the Wort

Boiling the wort is a crucial phase in the beer production process, as it serves to sterilize the liquid, extract the aromas and bitterness of the hops and prepare the wort for subsequent fermentation.

An essential aspect of the brewing process is the boiling of the wort, which serves multiple purposes, including the denaturation of proteins. This step is crucial for the quality of the final beer. Proteins in the wort can affect the clarity and head retention of the beer. If there are too many proteins, the beer may become hazy, while too few can result in poor foam production. During the boiling, proteins are denatured, meaning they are heated to the point where their structures are disrupted, and they coagulate.

This process helps in achieving the right protein balance in the wort. The denatured proteins, along with the hops that have been added for bitterness, flavor, and aroma, will eventually be separated from the wort after boiling. The separation of these solids from the liquid wort is typically achieved through a process known as the whirlpool. The whirlpool stage involves creating a circular motion in the wort, which causes the denser particles, including the denatured proteins and hop material, to collect at the center. This makes it easier to remove these solids, leaving behind a clearer wort that is then ready for cooling and fermentation. The whirlpool is a critical step in the brewing process, as it not only clarifies the wort but also contributes to the overall efficiency and quality of the beer. It prepares the wort for the next stages of brewing, ensuring that the fermentation process can proceed smoothly and effectively.

 The Kettle of Wort

The engine of the boiling phase is the wort kettle, a large stainless-steel vessel in which the wort is brought to boil. There are different types of kettles, which differ in the heating mode and the must circulation system.

Heated Kettles

In large-scale beer production, the use of internal heating coils within the brewing vessel is not very practical, as it necessitates the separation of too many components. A more efficient approach is to employ a double-walled kettle, where the space between the walls is heated, transferring the heat to the wort. This method avoids scorching the wort and ensures it is kept in motion for an even distribution of temperature.

The primary method used to maintain the wort’s motion and achieve the desired temperature distribution is through the dynamic flow of the wort’s heat. Understanding and utilizing the specific equipment for beer production is crucial to obtaining the desired outcome. This process requires knowledge of how to manage the heat transfer and the flow dynamics within the brewing system to ensure a consistent and high-quality beer production.

The Addition of Hops

During the boil, hops are added in stages to achieve the desired flavor and bitterness profile. The addition of hops is a crucial moment, as it largely determines the final organoleptic characteristics of the beer.

Circulation and Separation Systems

To ensure uniform boiling and optimal extraction of aromas and bitterness, the kettles are equipped with forced circulation systems for the wort. Furthermore, upon exiting the kettle, the wort passes through separation systems to remove solid residues.

In the brewing process, particularly on a professional scale, the whirlpool stage is a critical step that follows the boiling of the wort. After the wort has been boiled and the hops have been added, the mixture is then pumped into a separate vessel, often referred to as a whirlpool tank. This transfer is done using a tangential inlet, which sets the liquid into a spinning motion. As the wort circulates within the whirlpool tank, a centrifugal force is created. This force causes the liquid to move outward, while the lighter particles, such as hop material and denatured proteins, are drawn towards the center. The clear liquid remains on the outside of the vortex, while the solids collect in the middle. This separation method is highly efficient and allows for the easy removal of the solid particles from the wort. Once the solids have been concentrated in the center, they can be discarded, leaving behind a clarified wort that is ready for cooling and fermentation.

The whirlpool process is widely used in almost all professional breweries due to its effectiveness in separating the trub (the collection of hop and protein solids) from the wort. It is a key step in achieving a clearer beer and ensuring that the fermentation process can proceed with a higher quality wort.

Technological innovations

Even in the boiling phase, the brewing industry has adopted technological innovations to improve the efficiency and quality of the process. For example, lower energy consumption heating systems have been developed, such as steam boilers or wort recirculation systems.

5. Fermentation and Maturation

Fermentation and Maturation: Where the Magic of Beer is Born

Fermentation and maturation are the final phases of the beer production process, in which the biochemical transformations that give the beer its characteristic sensorial profile take place. Here the fundamental role of yeast comes into play, the absolute protagonist of this fascinating metamorphosis.

Alcoholic Fermentation

Once the wort has been carefully prepared, it is inoculated with a selected strain of yeast. The yeast, thanks to its enzymatic activity, converts the sugars present in the must into ethanol and carbon dioxide.

This process, known as alcoholic fermentation, is guided by parameters such as temperature, pH and oxygenation, carefully controlled to promote optimal yeast activity and the formation of the desired compounds.

The different species and strains of yeast impart unique flavor and flavor profiles to the beer, making each beer a once-in-a-lifetime creation.

Maturation and Clarification

Once alcoholic fermentation is completed, the beer enters a maturation phase, during which further biochemical and clarification transformations take place.

During maturation, residual yeast and other insoluble compounds precipitate, resulting in a clear, bright beer. Furthermore, secondary biochemical reactions lead to the formation of new aromas and the stabilization of the sensory profile.

The use of advanced technologies, such as temperature-controlled fermentation and maturation tanks, allows these delicate biochemical processes to be precisely managed.

6. Bottling and Carbonation

After maturation, the beer is filtered or not, pasteurized (if necessary) and bottled.

Adding sugar to the bottle is a practice that some home brewers might use, but it is not a method employed by professional breweries. In professional brewing, the carbonation process is much more controlled and precise. Here’s a more accurate description of how carbonation is typically achieved in modern breweries: Firstly, for certain beers, breweries might add a sugary solution or unfermented wort taken from a similar or identical beer production batch.

However, for bottle conditioning in modern breweries, the process can be different. It involves carefully monitoring the fermented wort before maturation, ensuring there is no fermentable sugar content left, and timing the bottling process to capture the right number of residual sugars to generate the desired fermentation in the bottle. Secondly, once the beer has been filtered and/or pasteurized, adding sugar will not have any effect on carbonation, as the yeast has been removed. Most industrial beers are produced this way, with no yeast remaining in the bottle. For these beers, carbonation is achieved through a different process. To carbonate beer in a controlled manner after filtration, breweries use a counter-pressure filling method. This involves filling the bottles with carbon dioxide (CO2) dissolved into the liquid during fermentation in a pressurized tank. The CO2 is maintained in the liquid, and the beer is then bottled under pressure to ensure carbonation. This method guarantees a consistent level of carbonation and quality in the final product.

The Importance of Innovation

In the fermentation and maturation phase, the brewing industry has adopted technological innovations to improve process control and the quality of the final product. From the use of temperature-controlled fermentation systems to new yeast strains selected for specific aromatic profiles, every step is aimed at enhancing the complexity and uniqueness of this fascinating drink.

Conclusion

Beer brewing is a fascinating combination of science, art and tradition. From ancient malting techniques to the adoption of cutting-edge technologies, every stage of the process contributes to creating that unique and inimitable drink that is beer. Exploring this world is a fascinating journey through centuries of history and innovation. Digging deeper into the processes, you appreciate the importance of quickly capturing and analyzing real-time data to monitor aroma, taste and color output. Stay connected to discover the use of industry 4.0 technologies in this ancient process. Follow us to stay informed about the latest news!

Sources:

POLLUTANT RELEASE ESTIMATION TECHNIQUE MANUAL FOR BEER PRODUCTION Supported by: United Nation Institute for Training and Research (UNITAR) Prepared by: PRTR Project Management Unit Department of Hazardous Substance Management General Directorate of Environmental Protection Ministry of Environment

Innovative beer-brewing of typical, old and healthy wheat varieties to boost their spreading Lorenzo Albanese, Rosaria Ciriminna, Francesco Meneguzzo, Mario Pagliaro

Progress in brewing science and beer production CW Bamforth

Review: Beer Production Aroh, Kenechukwu. Uchechukwu September, 2018

Process modelling and technology evaluation in brewing Bettina Muater-slawitsch, Matthäus Hubmann, Michael Murkovic, Christoph Brunner

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