Historic Beer Birthday: Hans Adolf Krebs

Today is the birthday of Hans Adolf Krebs (August 25, 1900-November 22, 1981). He was a German-born British physician and biochemist. He was the pioneer scientist in study of cellular respiration, a biochemical pathway in cells for production of energy. He is best known for his discoveries of two important chemical reactions in the body, namely the urea cycle and the citric acid cycle. The latter, the key sequence of metabolic reactions that produces energy in cells, often eponymously known as the “Krebs cycle,” earned him a Nobel Prize in Physiology or Medicine in 1953. And it’s the Krebs cycle that is his relation to brewing, as it’s also known as the respiratory phase, the second aerobic state of the fermentation process immediately following the lag period.


Here’s a description of the Krebs cycle from Life Fermented:

The Krebs cycle, also known as the tricarboxylic acid (TCA) cycle or the citric acid cycle, is a circular and repeating set of reactions which requires oxygen. In beer making, this would occur in the first stage of fermentation when the yeast is pitched into a well aerated wort, and carries on until all oxygen is used up.
Pyruvate (are you tired of this word yet?) is first converted to acetyl-CoA (pronounced “Co-A”) in the following reaction:

pyruvate + 2 NAD+ + CoA-SH → acetyl-CoA + CO2 + NADH, with the help of the pyruvate dehydrogenase (PDH) complex. Note that this is the first time CO2 is produced, and yet more NADH is generated.

This acetyl-CoA then enters into a cycle of reactions which nets two molecules of CO2, one GTP (guanosine triphosphate, another unit of energy equivalent to ATP), three NADH, and one FADH2 (flavin adenine dinucleotide, which functions similarly to NADH). After the cycle completes, another acetyl-CoA molecule enters and the cycle repeats itself.

But wait, this just made more NADH, and we need to regenerate NAD+ so glycolysis can continue. Both the NADH and FADH2 now donate their electrons to a process called the electron transport chain/ oxidative phosphorylation. The result is a return of NAD to the NAD+ state, and a large amount of ATP cellular energy.

Because the Krebs cycle is so efficient at producing ATP energy units, this is the yeast’s preferred pathway. But, you’ll notice a rather conspicuous absence: ethanol. This is only formed in the absence of oxygen.

NPG x88332; Sir Hans Adolf Krebs

Here’s a biography of Krebs, from the Nobel Prize website:

Sir Hans Adolf Krebs was born at Hildesheim, Germany, on August 25th, 1900. He is the son of Georg Krebs, M.D., an ear, nose, and throat surgeon of that city, and his wife Alma, née Davidson.

Krebs was educated at the Gymnasium Andreanum at Hildesheim and between the years 1918 and 1923 he studied medicine at the Universities of Göttingen, Freiburg-im-Breisgau, and Berlin. After one year at the Third Medical Clinic of the University of Berlin he took, in 1925, his M.D. degree at the University of Hamburg and then spent one year studying chemistry at Berlin. In 1926 he was appointed Assistant to Professor Otto Warburg at the Kaiser Wilhelm Institute for Biology at Berlin-Dahlem, where he remained until 1930.

In I930, he returned to hospital work, first at the Municipal Hospital at Altona under Professor L. Lichtwitz and later at the Medical Clinic of the University of Freiburg-im-Breisgau under Professor S. J. Thannhauser.

In June 1933, the National Socialist Government terminated his appointment and he went, at the invitation of Sir Frederick Gowland Hopkins, to the School of Biochemistry, Cambridge, where he held a Rockefeller Studentship until 1934, when he was appointed Demonstrator of Biochemistry in the University of Cambridge.

In 1935, he was appointed Lecturer in Pharmacology at the University of Sheffield, and in 1938 Lecturer-in-Charge of the Department of Biochemistry then newly founded there.

In 1945 this appointment was raised to that of Professor, and of Director of a Medical Research Council’s research unit established in his Department. In 1954 he was appointed Whitley Professor of Biochemistry in the University of Oxford and the Medical Research Council’s Unit for Research in Cell Metabolism was transferred to Oxford.

Professor Krebs’ researches have been mainly concerned with various aspects of intermediary metabolism. Among the subjects he has studied are the synthesis of urea in the mammalian liver, the synthesis of uric acid and purine bases in birds, the intermediary stages of the oxidation of foodstuffs, the mechanism of the active transport of electrolytes and the relations between cell respiration and the generation of adenosine polyphosphates.

Among his many publications is the remarkable survey of energy transformations in living matter, published in 1957, in collaboration with H. L. Kornberg, which discusses the complex chemical processes which provide living organisms with high-energy phosphate by way of what is known as the Krebs or citric acid cycle.

Krebs was elected a Fellow of the Royal Society of London in 1947. In 1954 the Royal Medal of the Royal Society, and in 1958 the Gold Medal of the Netherlands Society for Physics, Medical Science and Surgery were conferred upon him. He was knighted in 1958. He holds honorary degrees of the Universities of Chicago, Freiburg-im-Breisgau, Paris, Glasgow, London, Sheffield, Leicester, Berlin (Humboldt University), and Jerusalem.

He married Margaret Cicely Fieldhouse, of Wickersley, Yorkshire, in 1938. They have two sons, Paul and John, and one daughter, Helen.

And in the Microbe Wiki, on a page entitled “Saccharomyces cerevisiae use and function in alcohol production,” under a section called “Fermentation of alchohol,” the Krebs cycle is placed in its portion in the fermentation process:

Saccharomyces cerevisiae is able to perform both aerobic and anaerobic respiration. The process begins with the yeast breaking down the different forms of sugar in the wort. The types of sugars typically found in wort are the monosaccharides glucose and fructose. These sugars contain a single hexose, which is composed of 6 carbon atoms in the molecular formula C6H12O6. Disaccharides are formed when two monosaccharides join together. Typical disaccharides in the wort are galactose, sucrose, and maltose. The third type of fermentable sugar in the wort is a trisaccharide. This trisaccharide is formed when three monosccharides join together. Maltotriose is the trisaccharide commonly found in the wort and is composed of three glucose molecules. The wort does contain other sugars such as dextrins but it is not fermentable by yeast10. These dextrins contain four monosaccarides joined together. In order for the yeast to use the disaccharides and trisaccharides they first must be broken down to monosaccharides. The yeast does this by using different enzymes both inside and outside the cell. The enzyme invertase is used to break down sucrose into glucose and fructose. The invertase catalyzes the hydrolysis of the sucrose by breaking the O-C (fructose bond). The other enzyme used is maltase, which breaks down maltose and maltotriose into glucose inside the cell. The enzyme does this by catalyzing the hydrolysis of the sugars by breaking the glycosidic bond holding the glucose molecules together.

Once the sugars are broken down into monosaccharides the yeast can use them. The primary step is called glycolysis. In this process the glucose is converted to pyruvate using different enzymes in a series of chemical modifications. The electrons from glucose end up being transferred to energy carrying molecules like NAD+ to form NADH. ATP is also formed when phosphates are transferred from high-energy intermediates of glycolysis to ADP. In the presence of oxygen aerobic respiration can occur. This occurs in the mitochondria of the yeast. The energy of the pyruvate is extracted when it goes through metabolic processes like the Krebs cycle. The products of this type of metabolism are ATP, H2O, and CO2. However if there is no oxygen present and an abundance of sugars, as in the wort, the yeast undergo alcoholic fermentation. This type of metabolism yields much smaller amounts of energy when compared to aerobic respiration. However, because of the large supply of sugars from the different grains the wort is a very good environment for fermentative growth. The alcoholic fermentation begins with the two pyruvate acquired from glycolysis. These two pyruvate are decarboxylated by pyruvate decarboxylase to form two acetaldehydes and CO2. The CO2 is the gas that is observed during fermentation as bubbles that float to the top of the wort creating the kräusen or beer head, the foam that is very characteristic of a freshly poured beer. Pyruvate decarboxylase is a homotetramer meaning it contains four identical subunits. This also means that is has four active sites. The active sites are where the pyruvate reacts with the cofactors thiamine pyrophosphate (TPP) and magnesium to remove the carbon dioxide9. The final step to form alcohol is the addition of a hydrogen ion to the aldehyde to form ethanol. This hydrogen ion is from the NADH made during glycolysis and converts back to NAD+. The ethanol is originally believed to serve as an antibiotic against other microbes. This form of defense ensures that bacteria do not grow in the wort, thus ruining the beer with off flavors. However recently with the boom of craft beer different bacteria have been purposefully added to create what is known as sour beer. The sour taste comes from the waste products of the bacteria.


To learn more about the Krebs cycle check out this video from the University of Oklahoma’s Chemistry of Beer – Unit 7 – Chemical Concepts: Krebs Cycle:

Historic Beer Birthday: Johan Kjeldahl

Today is the birthday of Johan Gustav Christoffer Thorsager Kjeldahl (August 16, 1849-July 18, 1900) He was a Danish chemist who developed a method for determining the amount of nitrogen in certain organic compounds using a laboratory technique which was named the Kjeldahl method after him.


Kjeldahl worked in Copenhagen at the Carlsberg Laboratory, associated with Carlsberg Brewery, where he was head of the Chemistry department from 1876 to 1900.

He was given the job to determine the amount of protein in the grain used in the malt industry. Less protein meant more beer. Kjeldahl found the answer was in developing a technique to determine nitrogen with accuracy but existing methods in analytical chemistry related to proteins and biochemistry at the time were far from accurate.

A painting by Otto Haslund of Johan Kjeldahl.

His discovery became known as the Kjeldahl Method


The method consists of heating a substance with sulphuric acid, which decomposes the organic substance by oxidation to liberate the reduced nitrogen as ammonium sulphate. In this step potassium sulphate is added to increase the boiling point of the medium (from 337 °C to 373 °C) . Chemical decomposition of the sample is complete when the initially very dark-coloured medium has become clear and colourless.

The solution is then distilled with a small quantity of sodium hydroxide, which converts the ammonium salt to ammonia. The amount of ammonia present, and thus the amount of nitrogen present in the sample, is determined by back titration. The end of the condenser is dipped into a solution of boric acid. The ammonia reacts with the acid and the remainder of the acid is then titrated with a sodium carbonate solution by way of a methyl orange pH indicator.


In practice, this analysis is largely automated; specific catalysts accelerate the decomposition. Originally, the catalyst of choice was mercuric oxide. However, while it was very effective, health concerns resulted in it being replaced by cupric sulfate. Cupric sulfate was not as efficient as mercuric oxide, and yielded lower protein results. It was soon supplemented with titanium dioxide, which is currently the approved catalyst in all of the methods of analysis for protein in the Official Methods and Recommended Practices of AOAC International.

And Velp Scientifica also has an explanation of his method, which is still in use today.

Kjeldahl (center) in his laboratory.

Historic Beer Birthday: Max Schwarz

Today is the birthday of Max Schwarz (July 29, 1863-February 7, 1901). He was the son of Anton Schwarz, who owned the magazine/journal American Brewer, which he turned into a serious scientific journal, writing many of the articles himself, and is credited with helping the entire industry improve its standards and processes. His son Max took over as publisher of the American Brewer when he passed away.


He was also mentioned in his father’s entry in the Jewish Encyclopedia, published in 1906.

Schwarz’s eldest son, Max Schwarz (b. in Budapest July 29, 1863; d. in New York city Feb. 7, 1901), succeeded him as editor of “The American Brewer” and principal of the Brewers’ Academy. He studied at the universities of Erlangen and Breslau and at the Polytechnic High School at Dresden. In 1880 he followed his father to the United States and became associated with him in many of his undertakings.

Both as editor and as principal of the academy he was very successful. Many of the essays in “The American Brewer,” especially those on chemistry, were written by him. He was a great advocate of the “pure beer” question in America.

And here’s his obituary from the American Brewers Review, Vol. XIV:



From Sewer To Brewer: Making Beer From Urine

If that headline surprised you, it really shouldn’t have. But like the beer made from John’s beard, or the chicha Dogfish Head made using human spit, it just sounds unappetizing. Until you remember that it’s all sterilized and boiled so the finished product is as sanitary as any other beer.

So when I saw the headline from Reuters, “Belgian scientists make novel water-from-urine machine,” and another, First We Feast, “Scientists Have Finally Discovered a Way to Turn Human Urine Into Beer,” my first thought was “sure, why not.” The story, it turns out, is about a team of researchers at Ghent University who have invented a “machine that turns urine into drinkable water and fertilizer using solar energy, a technique which could be applied in rural areas and developing countries.” The explanation of how it works, from Reuters:

While there are other options for treating waste water, the system applied at the University of Ghent uses a special membrane, is said to be energy-efficient and to be applicable in areas off the electricity grid.

“We’re able to recover fertilizer and drinking water from urine using just a simple process and solar energy,” said University of Ghent researcher Sebastiaan Derese.

The urine is collected in a big tank, heated in a solar-powered boiler before passing through the membrane where the water is recovered and nutrients such as potassium, nitrogen and phosphorus are separated.


First We Feast added:

The scientists recently put their invention to the test during a 10-day festival in Ghent. Using the hashtag #PeeForScience, the team encouraged festival-goers to stop by their stand and donate to the cause by relieving themselves. The researchers ended up collecting a whopping 1,000 liters of pee from everyone who participated.

The team believe its machine will have its biggest impact in rural areas, wherever water is scarce and throughout the third world. But apparently as in other projects the Ghent team was involved in, they’ll use some of the water collected to make beer. Program director Derese called this part of the plan “from sewer to brewer.”

There’s many old jokes about American beer being horse piss, so maybe now it really can be. If it reduces costs even a little, you know the megabrewers would be willing to give it a try.


Patent No. 3044879A: Anactinic Malt Product And Hop Extract Therefor

Today in 1962, US Patent 3044879 A was issued, an invention of William C. Herwig, Thomas L. Kissel, and Gilbert H. Koch, assigned to Miller Brewing, for his “Anactinic Malt Product and Hop Extract Therefor.” There’s no Abstract, although in the description it includes these claims:

This invention relates to manufacture of anactinic malt beverages such as beer and ale, and to intermediate products.

It is well known that beer and ale and similar malt beverages are produced from water, barley malt, adjuncts and hops. The malt and adjuncts furnish the carbohydrates and other growth essentials which make up the wort. This wort, boiled with hops, in turn forms the basic substance for fermentation in the fermenting tanks. The hops give the characteristic bitter flavor and pleasant aroma to the beer. They assist in preserving the beer and improve its foam holding capacity.

Unfortunately, beer and ale and other similar malt beverages are not stable to light. Light of both visible and-invisible wave lengths affects them adversely producing actinic damage in the form of a characteristic skunky odor. Such a beer is commonly known as light struck. The actinism is caused by chemical changes, producing compounds probably mercaptans in nature. Tests show that the olfactory threshold level of odoriferous compounds of this character is very low, in the range of a few parts per billion. This shows clearly the acute nature of the problem. 7 Many efforts have been made in the past to overcome this difficulty. Much time has been expended on packaging of beer and ale to exclude light. Colored bottles have been used and opaque packages are common. It is not uncommon to label them Do Not Expose to Light.

To compete with modern day merchandising, a malt beverage has to be removed from the case and put on the shelf, or at least a portion of the container is exposed for easy vision and access. Modern reach-in coolers have clear glass windows and fluorescent lights which aggravate the problems. Even canned beer or keg beer can be adversely affected by sunlight if, as is usually the’ case, it is drunk from a glass. glass to direct sunlight for a short a time as a few minutes will result in the impairment of the taste and production of the characteristic skunky odor. Beer at picnics and sporting events is often exposed for hours to direct sunlight. In such cases, the deleterious effects can be very marked.

q We have discovered a way to overcome the hazard of product exposure to light which forms the basis of our invention, and have thereby achieved a substantially anactinic malt beverage. The term anactinic is intended The exposure of beer in the 3,044,879 Patented July 17, 1962 bitterness in the finished product, but eliminate the photoactive elements thereof.

A still further object of the, present invention is to provide a method of treating hop extract in the presence of a reducing agent to provide a concentrated product having particular application in malt beverages production, whereby its use will not affect the desired characteristics of the beverage, but will eliminate photoactive elements therein.

The soft resins and oils, which are contained in the glands produced on the hops and known as lupulin glands, are valuable constituents of the hops as used ,in the brewing process. The soft resins consist principally of (a) the alpha acids, (b) the beta acids, and (c) the uncharacterized soft resins. The alpha acids are known as humulones and the beta acids are known as lupulones. The alpha acids are the source of antiseptic and bitter substances in beer. The beta acids or lupulones have low solubility in kettle wort and beer, thus do not appreciably enter into the brewing process.

It is known that chemical changes are made in the humulones during brewing resulting in the compounds known :as isohumulones, i.e. isohumulone, isocohumwlone, isoadhurnulone, and isoprehumulone. These isocompounds are formed in the kettle during the boiling stage of the brewing process, and we have discovered that these compounds are the ones that cause the beer to become sensitive to light in the presence of sulfhydryl comhumulone, and prehumulone, is isomerized to the corresponding isohumulones. It is known that during the isomerization of the humulones to isohumulones, a new side chain is formed which now contains a carbonyl group.

It is these isohumulones-isohumulone, isocohumuloue isoadhumulone, and isoprehumulone which we have found to be involved in the photochemical reaction with sulfhydryl compounds to produce the ‘actinic damage resulting in the characteristic light struck aroma.

to succinctly describe a beverage which will not be subject to actinic damage. The word is herein coined and is derived from the word -actinic plus the prefix an, meaning not. This is the Greek equivalent to the Latin in and consists of alpha privative plus nu movable.

We have found that three factors are necessary for the reaction causing malt beverages. to become light struck. They are photo energy in the wave length region of 1,000 to 10,000 angstroms, a sulfhydryl bearing compound, and a chemical component derived from the raw materials, hops, during the brewing process.

The primary object of the invention is to provide a hop extract and malt beverage that is stable to light and will not produce unpleasant olfactory characteristics.

A further object of the invention is to so treat the hops in malt beverages so as to retain the aroma, bouquet and We are of the belief that when the isohumulones are group can be altered by means of reduction to a secondary alcohol, and by such alternation, be prevented from reacting with the sulfhydryl groups normally present in beer components.


Patent No. 3193395A: Concentration Of Beer By Crystallization

Today in 1965, US Patent 3193395 A was issued, an invention of Merritt V DeLano Jr. and Donald C. Tabler, assigned to the Phillips Petroleum Co., for their “Concentration of Beer by Crystallization.” There’s no Abstract, although in the description it includes this summary:

It is common to concentrate aqueous solutions by evaporation of water for the sake of economy in storage and shipping and to preserve the product. Removal of water by evaporation from a food product and particularly from a beverage results in the removal of essential components which affect the freshness and flavor of the beverage so that it cannot be restored to its original quality merely by the addition of water. This disadvantage can be overcome in the concentration of beverages by using a crystallization process whereby the water is separated from non-aqueous components by freezing. It is known that when water freezes the ice is in a pure form so that water can be removed from aqueous solutions by this method without the loss of volatile materials essential to the quality thereof.

There is considerable interest in the concentration of beer by freezing. The beer as received from the fermenters can be concentrated to approximately 1A its original volume by freezing out much of the water present therein. If the beer is shipped in the concentrated form, considerable savings can be realized in freight. Also, the storage facilities for the beer concentrate can be reduced and it has been found that beer in the concentrated form can be stored for substantially longer periods of time without deterioration of avor. Even if the beer is immediately reconstituted, there is substantial advantage to the concentration process in employing the crystallization method since the cold beer concentrate can be filtered to produce in effect an accelerated lagering process. This greatly reduces the requirements for large inventories and refrigerated storage tanks now necessary in breweries.

In the above-mentioned patent to Thomas, 2,854,494, there is disclosed a process and apparatus for purifying crystals which involves moving a mixture of crystals and mother liquor through a purification column in which the crystals are passed in a compact mass into a body of crystal melt which is displaced back into the crystal mass. The purification column includes an upstream liquid removal zone, a middle reflux zone, and a downstream melting zone. Mother liquor is removed from the crystals in the liquid removal zone and the ice crystals are melted in the melting zone. A portion of the crystal melt is Withdrawn from the melting zone and the remainder is forced back into the crystal mass in the reflux zone.

This apparatus can be used very effectively in the freeze concentration of beer. The beer is cooled to form a slurry of ice crystal in a mother liquor which is a beer concentrate and the resulting slurry is passed into the crystal purification column. Substantially pure water water which is the crystal melt can be removed from the melting zone and the beer concentrate is removed from the liquid removal zone of the purification column. We have found, however, that in the application of this purification method to beer, considerable difficulty is encountered as a result of carbon dioxide evolving from the mother liquor in the purification column. This evolvement of carbon dioxide causes channeling within the 3,193,395 Patented July 6, 1965 crystal mass with resultant loss of efficiency of the purification column. It becomes apparent, therefore, that the removal of carbon dioxide from the beer prior to its introduction into the crystal purification column should provide a solution to this problem. It can be appreciated, however, that with the removal of carbon dioxide from the beer prior to concentration there is also a substantial danger of removing alcohol and some of the essential flavor components which the crystal concentration method is used to preserve.

According to our invention, beer is concentrated by the crystallization method employing a purification column as described and the problem of channeling within the purification column as a result of evolvement of carbon dioxide is overcome by the prior removal of carbon dioxide without any substantial removal of the essential components from the beer itself. Since carbon dioxide is always added to beer in a carbonation step prior to packaging, this prior removal of carbon dioxide from the beer before concentration does not pose any particular problem or introduce an additional step in the over-all process of treating the beer concentrate on reconstitution. According to our invention, an antifoam agent is first added to the beer as it comes from the fermenters. The beer is then cooled in order to freeze a substantial amount of the water present therein and form a relatively thick slurry. This slurry is then subjected to a vacuum and the slurry is agitated with the result that carbon dioxide is removed from the remaining liquid. The solids content of the slurry can then be adjusted if necessary for the concentration process and the slurry is passed into the purification column where the ice and mother liquor are separated as described above. In a preferred aspect of the invention, in the carbon dioxide removal step the beer is cooled so that the slurry has a high solids content and subsequently the slurry is warmed slightly and thereby thinned so that trapped bubbles of carbon dioxide are released. The slurry is then recooled to the proper solids content for passage to the purification column. By lowering the temperature of the beer in order to remove carbon dioxide so that a substantial amount of water is frozen, the solubility of the carbon dioxide in the overall slurry is reduced even though the reduced temperature permits higher solubility in the remaining liquid. Reducing the pressure permits substantially all of the carbon dioxide to be removed from the slurry and since the alcohol has a very low vapor pressure at the low temperatures employed, very little of this material is vaporized with the carbon dioxide. We have also found that the addition of the antifoam agent to the beer prior to cooling to form a slurry enables substantially complete removal of the carbon dioxide from the slurry whereas complete removal is not attained without this antifoam agent, apparently because of the formation of extremely fine bubbles of the gas within the crystal mass.

It is an object of our invention to provide an improved method of concentrating beer by crystallization. Another object is to provide a method of concentrating beer by using a crystal purification column. Still another object of our invention is to provide a method of removing carbon dioxide from beer prior to concentration of the crystal slurry of the beer in the purification column without removing substantial amounts of alcohol. Still another object is to provide a method of improving the efficiency of a crystal purification column in the concentration of beer by substantially complete removal of the carbon dioxide present in the beer prior to passage of the crystal slurry through the purification column.


Historic Beer Birthday: Max Delbrück

Today is the birthday of Max Emil Julius Delbrück (June 16, 1850-May 4, 1919). He was a German chemist who spent most of his career exploring the fermentation sciences.


His Wikipedia entry is short:

Delbrück was born in Bergen auf Rügen. He studied chemistry in Berlin and in Greifswald. In 1872 he was made assistant at the Academy of Trades in Berlin; in 1887 he was appointed instructor at the Agricultural College, and in 1899 was given a full professorship. The researches, carried out in part by Delbrück himself, in part under his guidance, resulted in technical contributions of the highest value to the fermentation industries. He was one of the editors of the Zeitschrift für Spiritusindustrie (1867), and of the Wochenschrift für Brauerei. He died in Berlin, aged 68.

And here’s his entry from Today in Science:

Max Emil Julius Delbrück was a German chemist who spent a forty-five year career leading development in the fermentation industry. He established a school for distillation workers, a glass factory for the manufacture of reliable apparatus and instruments, and an experimental distillery. Giving attention to the raw resources, he founded teaching and experimental institutions to improve cultivation of potatoes and hops. He researched physiology of yeast and application in the process of fermentation, production of pure cultures, and the action of enzymes. He started the journals Zeitschrift fur Spiritus-Industrie (1867) and Wochenschrift für Brauerei, for the alcohol and brewery industries, which he co-edited.


Over the years, I’ve found a few great Delbrück quotes:

Yeast is a machine.

          — Max Delbrück, from an 1884 lecture

With the sword of science and the armor of Practice, German beer will encircle the world.

          — Max Delbrück, from an address about yeast and fermentation in the
               brewery, to the German Brewing Congress as Director of the Experimental
               and Teaching Institute for Brewing in Berlin, June 1884


Historic Beer Birthday: Eduard Buchner

Today is the birthday of Eduard Buchner (May 20, 1860-August 13, 1917). Buchner was a German chemist and zymologist, and was awarded with Nobel Prize in Chemistry in 1907 for his work on fermentation.


This is a short biography from The Famous People:

Born into an educationally distinguished family, Buchner lost his father when he was barely eleven years old. His elder brother, Hans Buchner, helped him to get good education. However, financial crisis forced Eduard to give up his studies for a temporary phase and he spent this period working in preserving and canning factory. Later, he resumed his education under well-known scientists and very soon received his doctorate degree. He then began working on chemical fermentation. However, his experience at the canning factory did not really go waste. Many years later while working with his brother at the Hygiene Institute at Munich he remembered how juices were preserved by adding sugar to it and so to preserve the protein extract from the yeast cells, he added a concentrated doze of sucrose to it. What followed is history. Sugar in the presence of enzymes in the yeast broke into carbon dioxide and alcohol. Later he identified the enzyme as zymase. This chance discovery not only brought him Nobel Prize in Chemistry, but also brought about a revolution in the field of biochemistry.


Eduard Buchner is best remembered for his discovery of zymase, an enzyme mixture that promotes cell free fermentation. However, it was a chance discovery. He was then working in his brother’s laboratory in Munich trying to produce yeast cell free extracts, which the latter wanted to use in an application for immunology.

To preserve the protein in the yeast cells, Eduard Buchner added concentrated sucrose to it. Bubbles began to form soon enough. He realized that presence of enzymes in the yeast has broken down sugar into alcohol and carbon dioxide. Later, he identified this enzyme as zymase and showed that it can be extracted from yeast cells. This single discovery laid the foundation of modern biochemistry.


One of the most important aspects of his discovery proving that extracts from yeast cells could elicit fermentation is that it “contradicted a claim by Louis Pasteur that fermentation was an ‘expression of life’ and could occur only in living cells. Pasteur’s claim had put a decades-long brake on progress in fermentation research, according to an introductory speech at Buchner’s Nobel presentation. With Buchner’s results, “hitherto inaccessible territories have now been brought into the field of chemical research, and vast new prospects have been opened up to chemical science.”

In his studies, Buchner gathered liquid from crushed yeast cells. Then he demonstrated that components of the liquid, which he referred to as “zymases,” could independently produce alcohol in the presence of sugar. “Careful investigations have shown that the formation of carbon dioxide is accompanied by that of alcohol, and indeed in just the same proportions as in fermentation with live yeast,” Buchner noted in his Nobel speech.


This is a fuller biography from the Nobel Prize organization:

Eduard Buchner was born in Munich on May 20, 1860, the son of Dr. Ernst Buchner, Professor Extraordinary of Forensic Medicine and physician at the University, and Friederike née Martin.

He was originally destined for a commercial career but, after the early death of his father in 1872, his older brother Hans, ten years his senior, made it possible for him to take a more general education. He matriculated at the Grammar School in his birth-place and after a short period of study at the Munich Polytechnic in the chemical laboratory of E. Erlenmeyer senior, he started work in a preserve and canning factory, with which he later moved to Mombach on Mainz.

The problems of chemistry had greatly attracted him at the Polytechnic and in 1884 he turned afresh to new studies in pure science, mainly in chemistry with Adolf von Baeyer and in botany with Professor C. von Naegeli at the Botanic Institute, Munich.

It was at the latter, where he studied under the special supervision of his brother Hans (who later became well-known as a bacteriologist), that his first publication, Der Einfluss des Sauerstoffs auf Gärungen (The influence of oxygen on fermentations) saw the light in 1885. In the course of his research in organic chemistry he received special assistance and stimulation from T. Curtius and H. von Pechmann, who were assistants in the laboratory in those days.

The Lamont Scholarship awarded by the Philosophical Faculty for three years made it possible for him to continue his studies.

After one term in Erlangen in the laboratory of Otto Fischer, where meanwhile Curtius had been appointed director of the analytical department, he took his doctor’s degree in the University of Munich in 1888. The following year saw his appointment as Assistant Lecturer in the organic laboratory of A. von Baeyer, and in 1891 Lecturer at the University.

By means of a special monetary grant from von Baeyer, it was possible for Buchner to establish a small laboratory for the chemistry of fermentation and to give lectures and perform experiments on chemical fermentations. In 1893 the first experiments were made on the rupture of yeast cells; but because the Board of the Laboratory was of the opinion that “nothing will be achieved by this” – the grinding of the yeast cells had already been described during the past 40 years, which latter statement was confirmed by accurate study of the literature – the studies on the contents of yeast cells were set aside for three years.

In the autumn of 1893 Buchner took over the supervision of the analytical department in T. Curtius’ laboratory in the University of Kiel and established himself there, being granted the title of Professor in 1895.

In 1896 he was called as Professor Extraordinary for Analytical and Pharmaceutical Chemistry in the chemical laboratory of H. von Pechmann at the University of Tübingen.

During the autumn vacation in the same year his researches into the contents of the yeast cell were successfully recommenced in the Hygienic Institute in Munich, where his brother was on the Board of Directors. He was now able to work on a larger scale as the necessary facilities and funds were available.

On January 9, 1897, it was possible to send his first paper, Über alkoholische Gärung ohne Hefezellen (On alcoholic fermentation without yeast cells), to the editors of the Berichte der Deutschen Chemischen Gesellschaft.

In October, 1898, he was appointed to the Chair of General Chemistry in the Agricultural College in Berlin and he also held lectureships on agricultural chemistry and agricultural chemical experiments as well as on the fermentation questions of the sugar industry. In order to obtain adequate assistance for scientific research, and to be able to fully train his assistants himself, he became habilitated at the University of Berlin in 1900.

In 1909 he was transferred to the University of Breslau and from there, in 1911, to Würzburg. The results of Buchner’s discoveries on the alcoholic fermentation of sugar were set forth in the book Die Zymasegärung (Zymosis), 1903, in collaboration with his brother Professor Hans Buchner and Martin Hahn. He was awarded the Nobel Prize in 1907 for his biochemical investigations and his discovery of non-cellular fermentation.

Buchner married Lotte Stahl in 1900. When serving as a major in a field hospital at Folkschani in Roumania, he was wounded on August 3, 1917. Of these wounds received in action at the front, he died on the 13th of the same month.


Historic Beer Birthday: Emil Christian Hansen

Today is the birthday of Emil Christian Hansen (May 8, 1842-August 27, 1909). Hansen was a “Danish botanist who revolutionized beer-making through development of new ways to culture yeast. Born poor in Ribe, Denmark, he financed his education by writing novels. Though he never reached an M.Sc., in 1876, he received a gold medal for an essay on fungi, entitled “De danske Gjødningssvampe.” In 1879, he became superintendent of the Carlsberg breweries. In 1883, he successfully developed a cultivated yeast that revolutionized beer-making around the world, because Hansen by refusing to patent his method made it freely available to other brewers. He also proved there are different species of yeast. Hansen separated two species: Saccharomyces cerevisiae, an over-yeast (floating on the surface of the fermenting beer) and Saccharomyces carlsbergensis, an under-yeast (laying on the bottom of the liquid).


Here’s his entry from Encyclopedia Britannica:

Danish botanist who revolutionized the brewing industry by his discovery of a new method of cultivating pure strains of yeast.

Hansen, who began his working life as a journeyman house painter, received a Ph.D. in 1877 from the University of Copenhagen. Two years later he was appointed head of the physiology department at the Carlsberg Laboratory in Copenhagen, where he remained until his death. His research was concerned mainly with yeasts that convert carbohydrates to alcohol, and in 1888 he published an article that described his method for obtaining pure cultures of yeast. The yeast grown from these single strains was widely adopted in the bottom-fermentation brewing industries. Further investigations led him to the discovery of a number of species of yeast. He defined the characters of the different species and devised a system of classification. After further study he devised additional methods for the culture and isolation of certain species.

Emil Hansen as a young man.

This is how Carlsberg describes Hansen’s breakthrough in 1883:

The Carlsberg Laboratory made its first major scientific breakthrough when Dr. Emil Chr. Hansen developed a method for propagating pure yeast.

Fluctuations in the beer quality were not unknown at the time, but had until then been solved by thorough cleaning of all installations after suspension of production. If a brew failed, there was no use in pasteurising it; it had to be destroyed.

In 1883, the Old Carlsberg beer got infected with the beer disease and all efforts were made to find a solution to the problem.

Dr. Emil Chr. Hansen who joined the Carlsberg Laboratory in 1878 was examining the beer, and he found that it contained wild yeast. Through his studies and analyses, he discovered that only a few types of yeast (the pure yeast) are suitable for brewing, and he developed a technique to separate the pure yeast from the wild yeast cells. The problem had been solved, and the new Carlsberg yeast – Saccharomyces Carlsbergensis – was applied in the brewing process.

The propagating method revolutionised the brewing industry. Rather than to patent the process, Carlsberg published it with a detailed explanation so that anyone could build propagation equipment and use the method. Samples of the yeast – Saccharomyces Carlsbergensis – were sent to breweries around the world by request and young brewers came to Carlsberg to learn the skills.


This is the entry from Wikipedia on the history of Saccharomyces Carlsbergensis:

So-called bottom fermenting strains of brewing yeast were described as early as the 14th century in Nuremberg and have remained an indispensable part of both Franconian and Bavarian brewing culture in southern Germany through modern times. During the explosion of scientific mycological studies in the 19th century, the yeast responsible for producing these so-called “bottom fermentations” was finally given a taxonomical classification, Saccharomyces pastorianus, by the German Max Reess in 1870.

In 1883 the Dane Emil Hansen published the findings of his research at the Carlsberg brewery in Copenhagen and described the isolation of a favourable pure yeast culture that he labeled “Unterhefe Nr. I” (bottom-fermenting yeast no. 1), a culture that he identified as identical to the sample originally donated to Carlsberg in 1845 by the Spaten Brewery of Munich. This yeast soon went into industrial production in Copenhagen in 1884 as Carlberg yeast no. 1.

In 1904 Hansen published an important body of work where he reclassified the separate yeasts he worked with in terms of species, rather than as races or strains of the same species as he had previously done. Here Hansen classified a separate species of yeast isolated from the Carlsberg brewery as S. pastorianus, a name derived from and attributed to Reess 1870. This strain was admitted to the Centraalbureau voor Schimmelcultures (CBS) in 1935 as strain CBS 1538, Saccharomyces pastorianus Reess ex Hansen 1904. In a further publication in 1908, Hansen reclassified the original “Unterhefe Nr. I” as the new species Saccharomyces carlsbergensis and another yeast “Unterhefe Nr. II” as the new species Saccharomyces monacensis. The taxonomy was attributed to Hansen 1908 and the yeasts entered into the Centraalbureau voor Schimmelcultures in 1947 as CBS 1513 and CBS 1503 respectively.

Since the early 1900s, bottom-fermenting strains of brewery yeast have been typically classified as S. carlbergensis in scientific literature, and the earlier valid name assigned to a bottom-fermenting yeast by Reess in 1870 was rejected without merit. This situation was rectified using DNA-DNA reallocation techniques in 1985 when Vaughan-Martini & Kurtzman returned the species name to S. pastorianus under the type strain CBS 1538 and relegated the two former species assigned by Hansen in 1908, S. carlsbergensis CBS 1513 and S. monacensis CBS 1503, to the status of synonyms. These experiments also clearly revealed the hybrid nature of the lager brewing yeast species for the first time, even though one of the parental species was incorrectly classified in retrospect. Nonetheless, over the last decades of the 20th century, debate continued in scientific literature regarding the correct taxon, with authors using both names interchangeably to describe lager yeast.


Although most accounts mention that he wrote novels to put himself through school, one has a slightly different take, though I’m not sure how true it is. “Emil earned his bread and butter as a painter but he yearned for another life and left Ribe so he could study. He graduated from High School relatively late – he was 29 years old.”


Emil Christian Hansen, taken in 1908, a year before his death.

Patent No. 3175912A: Synthetic Organic Chemical Preservative For Beer

Today in 1965, US Patent 3175912 A was issued, an invention of John B. Bockelmann and Frede B. Strandskov, assigned to Schaefer Brewing Co., for their “Synthetic Organic Chemical Preservative For Beer.” There’s no Abstract, although in the description it includes this summary:

The present invention relates generally to the control of micro-biological growth in finished packaged beer and ale with a synthetic, organic chemical preservative of the general formula:

Wherein R is an aliphatic hydrocarbon radical; X is either a hydrogen atom (H), an alkali metal, e.g., sodium (Na) and potassium (K), or an alkaline earth metal, e.g., cal cium (Ca); and 11 is an integer equal to the valence of X. More particularly, this invention is directed to the preservation of finished beer with a chemical preservative of the Formula 1 wherein R is saturated hydrocarbon chain. This invention also encompasses a mixture of compounds of Formula 1 as a chemical preservative for finished packaged beer and ale.