• 4/14/2016

500 years German beer purity law: Interview with Professor Thomas Becker

“Does beer even have to be liquid?”

Professor Thomas Becker of the Chair of Brewing and Beverage Technology at Technical University of Munich (TUM) on the discussion surrounding the Reinheitsgebot – the German beer purity law –, the latest research projects and the beer of tomorrow.

Professor Thomas Becker testing the properties of a fresh brew in the TUM research brewery. (Photo: TUM/ A. Heddergott)
Professor Thomas Becker testing the properties of a fresh brew in the TUM research brewery. (Photo: TUM/ A. Heddergott)

TUM: The Reinheitsgebot stipulates that only four ingredients are permitted for brewing beer, yet Germany alone boasts over 3,500 different beers – how is that possible?

Professor Thomas Becker: This is something that’s not uncommon in food and drink – dairy, pasta and bakery products also require comparatively few ingredients. The only difference is that these products are not governed by anything comparable to the Reinheitsgebot. As far as beer goes, you can calculate relatively easily how many different variations are possible from one hundred types of malt, 200 types of hops and 200 types of yeast. In addition, many parts of the brewing process also offer the opportunity to change parameters - be it in terms of temperature or timeframe - and this effectively makes millions of combinations possible. The question of whether these variations make sense or taste good is of course another matter.

TUM: It is thought that around 90 percent of the beer consumed worldwide is so-called lager, and critics claim that it tastes the same everywhere. Only around ten or eleven different types of yeast are currently used from the roughly 200 available. Does your Department conduct research into the use of rare yeasts? T. B.: There has been a megatrend among consumers for several years across all product genres: people want individualization and customization. Nowadays, everyone wants to have something special! In brewing technology, that is why an increasing amount of research is being dedicated to how new aromas and nuances in taste can be achieved. I can influence the aroma of beer using raw ingredients like malt or hops, or I can do so by varying the process or even the yeast. Types of yeast which provide a new range of aromas therefore offer the chance to significantly change the character of the beer. However, there has been reluctance to try this over the last hundred years for fear of nasty surprises. Today, we have reached an age in which we have the analytical and technical capabilities to better manage and control yeast. That’s why we’re working very intensively on screening different types of yeast for the characteristics that they can impart in the product.

TUM: Is it true that staff or postgraduates from your Chair go into disused beer cellars and take test smears in an effort to uncover old strains of yeast?

T. B.: We do that too, yes! We are working on two projects which involve screening strains of yeast from Central Africa. We are analyzing the local products from the region which are fermented using wild yeasts and completely different strains. Recently, we have also been taking yeasts from Asia and examining the aromas they create. The interaction of the yeasts with the hops or malt then plays a role in the remainder of the process. In the end, however, we have to be able to control the yeast with the process technology in such a way that we will not be surprised by the end result. The aim is to create processes that can be reproduced, always resulting in the same good product.

TUM: How many substances are actually found in the beer on our supermarket shelves nowadays?

T. B.: The natural products malt, hops and yeast add a variety of substances into beer which can be enhanced in both their definition and concentration during the course of the brewing process. Most of these substances end up in the final product. We are still unsure of which of these are ultimately responsible for determining a beer’s characteristics and this topic is currently the focus of research.

TUM: How is the Reinheitsgebot to be viewed in the context of European legislation?

T. B.: European food labeling regulation, which is strongly influenced by the Reinheitsgebot in this area, regulates the definition of what beer actually is. According to this, you can brew beer and, in contrast to Bavaria, add E numbers, though these have to be declared on the product – and hardly anyone buys this type of beer. The only problem is the regulation framework, which is not fully defined at present. In other words: There is beer brewed according to the Reinheitsgebot, and there is beer brewed according to EU guidelines. But what about products that use other natural raw ingredients? These can already be produced today and placed on the market. But they can’t be referred to as beer. That is why the besondere Biere (“special beers”) label exists outside of Bavaria.

TUM: Are there any current research projects at TUM on the Reinheitsgebot?

T. B.: In the national context, the Reinheitsgebot is a framework within which we work. Let me draw a comparison, if I may: All research into automobiles is conducted based on the condition that cars have to ultimately be able to drive. In other words, the ability to drive is the automobile industry’s Reinheitsgebot. This only indirectly influences the creativity, innovation and use of new technologies or methods. In any case, this has neither a limiting nor inhibiting effect on work in this area. In the international environment, we operate within a different framework.

TUM: Do we still need the purity law nowadays?

T. B.: From my point of view as a scientist, I don’t really see the need to question this. It goes without saying that we have to be aware of the framework in which we conduct our scientific work. But in this context, the purity law is more of a boundary than anything else. In contrast, from the current consumer point of view, the purity law is probably today more up-to-date than ever. Consumers are placing greater emphasis on food that is pure, largely natural and free of any additives. The Reinheitsgebot guarantees this. That is certainly one reason why it is so widely accepted. It’s definitely possible to add to the characteristics of a beer using additives. Alternatively, master brewers can be so skilled in the brewing process that they are able to achieve these characteristics without the need for any additives. For me personally, I value the cultural history of the Reinheitsgebot far more than whether there are exactly three or four raw ingredients used in brewing.

TUM: What groundbreaking advancements have been made in beer research?

T. B.: The most groundbreaking of all was the discovery of yeast. The next important development was Linde’s refrigerating machine: this made it possible to brew beer in the way we know it today. Then it was the new opportunities provided by IT and automated technology in production workflows. Currently, we are attempting to integrate the basic principles of industry 4.0 concepts into the brewing process.

TUM: What is your point of view for beer brewing technology as it moves into the future?

T. B.: This links in to the global challenges. Beer brewing technology is becoming increasingly characteristic-driven and influenced by expectations on the end product as part of a reverse-engineering concept. This shakes up traditional production systems and paradigms. The focus is on which beer characteristics can be achieved with which technology and which method achieves them most sustainably. Another aspect is certainly whether the characteristics that consumers currently expect from beer will remain the same or have to be expanded. Do established beverages and foods have to be produced using the same raw ingredients as they have been up to now? Does beer even have to be liquid? Or will final production take place within private households using instant products? Are the production steps necessary in their current form and still sustainable in a changing industry environment? Can beverages or beer be produced to contain other physiological characteristics? I’m thinking along the lines of “nutraceuticals”.

TUM: Recently, everyone has been talking about the renaissance in brewing and beer culture – how did it come about?

T. B.: In the past, and still in some Central African countries today, beer was and is the only safe drink available. Water was or is tainted, meaning that beer was and still remains an everyday staple. Since this situation has changed, we’ve seen a growing desire for deriving more and more enjoyment from the drink – people want tasty and aromatic experiences. This is undoubtedly driven by the hype surrounding the craft beer scene. Similar to wine, beer is now viewed differently in terms of quality and it enjoys a more positive image. This is a good thing and broadens beer consumption patterns.

TUM: And what role does taste still play in the high-tech production of a modern beverage?

T. B.: As I mentioned, over the past 30 to 40 years, we’ve started to expect that foodstuffs should do more than just cover our basic requirements: We expect flavor and aromas. I believe that this will be supplemented by expectations of additional advantages in a few years time. This is already the case in the Asia. Can a product help me to live to be 120 years old? That is what we will expect from food and drink in the future.

High resolution images


Professor Thomas Becker
Chair of Brewing and Beverage Technology
Weihenstephaner Steig 20
85354 Freising
Phone: +49 8161/71 - 3262
E-Mail: tbspam prevention@tum.de

Technical University of Munich

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