- After 8,000 Years of Brewing We may Finally be Getting Better Beer!
- Brewing Craft Beers: it’s All in the Genes
- An Old Industry Adopts New Ways
Later in this post I’ll get to nucleic acids, but let’s start with some brewing statistics that I think you’ll find impressive regardless of whether you drink beer, sip wine, imbibe spirits, or even abstain from alcohol.
Beer is very popular, based on worldwide statistics for beer consumption that speak volumes—pun intended. From one report, I estimated that this year about 200 billion liters of beer will be drunk—no pun intended. Using the real-time Population Clock (which, BTW, is almost scary to watch), I reckon that there are about 5 billion not-too-young-or-old potential beer drinkers on the planet, so that’s 40 liters of beer this year for each of these folks.
Another report I found states that, based on total volume, China consumes about 50 billion liters of beer each year, out-drinking its nearest rival (the United States) by more than 2x! The 24 billion liters consumed by the US, surpasses 3rd place Brazil who consumes 14 billion liters annually. Russia and Germany round out the top five at 9 billion liters each.
If you’re wondering about consumption on a per capita basis, a rank-ordered list of the top 50 countries is available here, with Czech Republic 1st at a whopping ~150 liters/person and India 50th at only ~2 liters per person. Notably, the US is 14th at ~77 liters per person.
Clearly, beer is thoroughly enjoyed around the world, so let’s explore the brewing process in a bit more detail. Brewing is simply the production of beer via the breakdown of starch and fermentation of sugar, which, according to Wikipedia, has been going on since around 6,000 BC. Archaeological evidence suggests most emerging civilizations starting with ancient Egypt and Mesopotamia (which is now Iraq) brewed beer in some fashion.
Fast forward about 7,500 years to 1487 AD, when Albert IV, Duke of Bavaria promulgated the Reinheitsgebot (German for “purity order”), sometimes called the “German Beer Purity Law,” specifying three ingredients—water, malt and hops—for the brewing of beer. Since this time-period precedes microbiology, yeast—the necessary fourth ingredient—was not explicitly specified but was fortuitously present in one or more of the other three ingredients.
I know you are familiar with the first ingredient, water, so let’s skip to the good stuff. Malts are derived from cereal grains—primarily barley. When fermented, malt develops enzymes such as proteases, which produce sugars to feed the yeast during the brewing process. Hops are the female flower clusters, or seed cones, of the hop vine Humulus lupulus, and are used as flavor and preservatives in beer. Hops had been used for medicinal and food flavoring purposes since Roman times. By the 7th century, Carolingian monasteries (in what is now Germany) were using hops to make beer, though it wasn’t until the 13th century that widespread cultivation of hops for use in beer was recorded.
While we’re about to discuss yeast and it’s connection to nucleic acid analysis, it’s worth mentioning that hop-derived flavors have led to a number of contemporary genetic analyses. If you’re a fanatical “hop head” beer lover and/or interested in nucleic acid-based applications related to hops, you may find this publication by the Hopsteiner company to be interesting. This study represents the use of SNPs as molecular markers to more efficiently track favorable traits (e.g., flavor and aroma) during cultivation of new hops.
It’s all in the Yeast!
Although hops are a major contributor to the flavor and aroma of beer, these enjoyable properties also come from the byproduct of yeast growth during the fermentation process. These byproducts form carbon dioxide and, some would say most importantly, alcohol—without which beer would have far less popularity.
The dominant types of yeast used to make beer are Saccharomyces cerevisiae, known as ale yeast, and Saccharomyces uvarum, known as lager yeast. Also popular are Brettanomyces, which ferments lambics—a type of Belgian beer—and Torulaspora delbrueckii, which ferments Bavarian weissbier. Before the role of yeast in fermentation was understood, fermentation involved wild or airborne yeasts, and a few styles such as lambics mentioned above still use this method today. Emil Christian Hansen, a Danish biochemist employed by the Carlsberg Laboratory, developed pure yeast cultures which were introduced into the Carlsberg brewery in 1883, and pure yeast strains are now the main fermenting source used worldwide.
Since there are thousands of possible Saccharomyces cerevisiae available for brewing beer and they all look similar, it is critical to identify the “good” yeasts and to reject the undesirable, “bad” yeasts. This is where modern nucleic acid-based analysis comes into play, providing tools for characterizing genes responsible for desirable properties of beer.
The Genes of Craft Beer
Clearly yeast is critical to the flavor and aroma of beer. These seemingly simple organisms have been studied extensively, but the connection between the genetic makeup of the yeast and the brewing properties that result from it are not well understood. Recently, two research teams set out to change this and hopefully determine what in the yeast’s genetic code is responsible for the flavor profile they produce.
The two labs participating in this project are White Labs, a Southern California yeast distributor, and a Belgium lab formed by a collaboration between the Flanders Institute for Biotechnology and the University of Leuven. The researchers involved in this project have sequenced more than 240 strains of yeast from around the world. They will use this sequencing data and the information from over 2,000 batches of beer to try to generate new yeast strands that exhibit particular flavors and properties. Dr. Kevin Verstrepen, director of the Belgian lab involved in this study, says “in a few years we might be drinking beers that are far different and more interesting than those that currently exist.”
Click here to read more about this project in an article reported by William Herkewitz of The New York Times.
The Beer Industry Comes into the 21st Century
The project discussed above represents the remarkable pace of advancement in sequencing as well as a paradigm shift within the beer industry itself. We can all remember how long and costly the Human Genome Project was (almost 10 years and $3 billion, if you lost track). Just over a decade later, a complete yeast genome can be sequenced in a matter of days for a few thousand dollars. But what’s possible through science is meaningless if brewers refuse to adopt the technology. As stated by Randy W. Schekman, a yeast geneticist at the University of California, Berkeley, “until recently, the brewing industry has been remarkably resistant to using the techniques of genetics and molecular biology to improve their brewing strains. It’s long overdue that someone has actually delved into the molecular basis between the differences in brewing strains.
I agree—8,000 years is definitely a long time! I look forward to seeing—and hopefully tasting—the results of this nucleic acid-based analysis coming soon to a brewery near me. As usual, your comments are welcomed.
Cheers! Santé! Prost! Salute! Nazdrowie!
Intrigued by the role of yeast in brewing, I did a Google Scholar search of “flavor compounds” (all the words) combined with “brewers yeast” (exact phrase) for publications since 2010. Here’s a sampling of found snippets that seemed quite interesting to me:
EJ Pires, JA Teixeira, T Brányik, AA Vicente – Applied microbiology and …, 2014 – Springer… Delvaux FR (2009) Impact of pitching rate on yeast fermentation performance and beer flavour. …T, Ferreira IM (2013) Evaluation of brewer’s spent yeast to produce flavor enhancer nucleotides …HP (1978) The isolation and identification of new staling related compounds form beer …
CT Duong, L Strack, M Futschik, Y Katou, Y Nakao… – Metabolic …, 2011 – Elsevier… in optimizing their yeast strains, particularly with regard to beer stability, the development of novel flavors and economics of … Diacetyl has a butter-like flavor and is particularly undesirable in lager beers. … The latter compound is an intermediate of the valine biosynthetic pathway. …
Y He, J Dong, H Yin, P Chen, H Lin… – Journal of the Institute …, 2014 – Wiley Online Library… the understanding of gene-regulating mechanisms and biosynthetic pathways of aroma-active compounds during yeast … JP, Winderickx, J., Thevelein, JM, Pretorius, IS, and Delvaux, FR (2003) Flavor-active esters … Part I: Flavour interaction between principal volatiles, Tech. …