A Bestiary is an old-fashioned idea, from the Middles Ages, where various animals and other creatures, often fanciful, mythical and fictitious, were illustrated, and then there was a detailed description of each beast, usually accompanied by an allegorical story with a moral or religious teaching. You can see examples of many of these imaginary creatures at the Medieval Bestiary. A Los Angeles illustrator and graphic designer, Ian O’Phelan, has created a modern version, which he calls a “Beer Bestiary.” With just four mythical creatures in his bestiary, his fantastic four you’ll likely recognize, if not individually, at least for what they can become as a superhero team, your next beer.
There was an interesting story posted on Popular Science, specifically their BeerSci series. They did a great job of spinning the story as a love story, albeit an unusual one between fruit flies and brewer’s yeast, especially since the original title of the study they’re reporting on was The Fungal Aroma Gene ATF1 Promotes Dispersal of Yeast Cells through Insect Vectors. But it is, and in How Flies Are Responsible For Beer’s Tasty, Fruity Smells, they detail how,”[i]n a series of experiments, biologists from several institutes in Belgium demonstrated that brewer’s yeast makes fruity, floral smells to attract fruit flies. In the wild, yeast might live on rotting fruit and entice flies to come to them there. Yeast and flies’ relationship benefits them both, the biologists found. Previous studies have found that eating yeast helps fruit fly larva develop faster and survive better. This new study found that fruit flies help spread yeast to new environments, like a bee spreading pollen.” In effect, their study demonstrates “the co-evolution of two species.”
Here’s the summary from the original, published in Cell Reports.
Yeast cells produce various volatile metabolites that are key contributors to the pleasing fruity and flowery aroma of fermented beverages. Several of these fruity metabolites, including isoamyl acetate and ethyl acetate, are produced by a dedicated enzyme, the alcohol acetyl transferase Atf1. However, despite much research, the physiological role of acetate ester formation in yeast remains unknown. Using a combination of molecular biology, neurobiology, and behavioral tests, we demonstrate that deletion of ATF1 alters the olfactory response in the antennal lobe of fruit flies that feed on yeast cells. The flies are much less attracted to the mutant yeast cells, and this in turn results in reduced dispersal of the mutant yeast cells by the flies. Together, our results uncover the molecular details of an intriguing aroma-based communication and mutualism between microbes and their insect vectors. Similar mechanisms may exist in other microbes, including microbes on flowering plants and pathogens.
You can also read the entire study as a pdf, but to get a sense of what it all means, read Francie Diep’s How Flies Are Responsible For Beer’s Tasty, Fruity Smells and keep in mind her warning from the outset. “Sorry, but brewer’s yeast did not evolve for you.” Perhaps not, but at least we can still reap the benefits of the relationship between those fruit flies and the yeast used to create delicious beer.
Today is the 46th birthday of Chris White. Chris founded the yeast company White Labs in 1995 and he’s also on the faculty of the Siebel Institute. He’s also a fixture at virtually every brewing industry and homebrewing conference. Join me in wishing Chris a very happy birthday.
Chris and his brother Mike bookending Chuck, from Green Fash Brewing, Natalie Cilurzo, from Russian River Brewing, John Harris, from Full Sail Brewing, and Vinnie Cilurzo, also from Russian River, at CBC in Austin, Texas in 2007.
[Note: last two photos purloined from Facebook.]
Here’s a fun little project I stumbled upon, someone created a series of Cross-Stitched Germs and Microbes. The needlepoint creations include over a dozen tiny creatures, including Beer Yeast. To make your own, visit Watty’s Wall Stuff on Etsy. She has individual patterns you can buy or sets, if you’re feeling crafty.
Here’s an interesting journal article for the yeast wrangler in you to geek out on. Genome Sequence of Saccharomyces carlsbergensis, the World’s First Pure Culture Lager Yeast details the efforts of Andrea Walther, Ana Hesselbart and Jürgen Wendland from the Carlsberg Laboratory to get a handle on the origins of modern lager yeast using more modern gene sequencing tools. Here’s the wonderfully obtuse explanation from the Abstract:
Lager yeast beer production was revolutionized by the introduction of pure culture strains. The first established lager yeast strain is known as the bottom fermenting Saccharomyces carlsbergensis, which was originally termed Unterhefe No.1 by Emil Chr. Hansen and used in production in since 1883. S. carlsbergensis belongs to group I/Saaz-type lager yeast strains and is better adapted to cold growth conditions than group II/Frohberg-type lager yeasts, e.g. the Weihenstephan strain WS34/70. Here, we sequenced S. carlsbergensis using next generation sequencing technologies. Lager yeasts are descendants from hybrids formed between a Saccharomyces cerevisiae parent and a parent similar to Saccharomyces eubayanus. Accordingly, the S. carlsbergensis 19.5 Mb genome is substantially larger than the 12 Mb S. cerevisiae genome. Based on the sequence scaffolds, synteny to the S. cerevisae genome, and by using directed PCRs for gap closure we generated a chromosomal map of S. carlsbergensis consisting of 29 unique chromosomes. We present evidence for genome and chromosome evolution within S. carlsbergensis via chromosome loss and loss of heterozygosity specifically of parts derived from the S. cerevisiae parent. Based on our sequence data and via FACS analysis we determined the ploidy of S. carlsbergensis. This inferred that this strain is basically triploid with a diploid S. eubayanus and haploid S. cerevisiae genome content. In contrast the Weihenstephan strain, which we re-sequenced, is essentially tetraploid composed of two diploid S. cerevisiae and S. eubayanus genomes. Based on conserved translocations between the parental genomes in S. carlsbergensis and the Weihenstephan strain we propose a joint evolutionary ancestry for lager yeast strains.
If that made your head spin, try the full article, which was released in full online at the end of February. It will be published in the journal G3: Genes, Genomes, Genetics in a future issue. It’s fascinating reading.
Today’s beer video, in honor of it being Sour Sunday, is a film of a talk given by Jeff Clawson, who’s the Pilot Brewery Manager at Oregon State University’s Food Science & Technology Department. In the 23-minute video, Clawson “discusses a recent study on sour beers at a Science Pub event at the Calapooia Brewery in Albany, Oregon. OSU is one of the world’s leaders in research on hops and the brewing sciences, and many graduates of the fermentation sciences programs go on to have a huge impact in the industry.”
Here’s another interesting post on brewing science from Popular Science‘s BeerSci series. If you’re reading the Bulletin, chances are you’re already pretty familiar with the question What Is The Difference Between A Lager And An Ale? But author Martha Harbison gives a good overview of the technical differences in layman’s terms and goes into yeast’s history. It’s a great tale, which she refers to hilariously as a “unicellular soap opera.”
After my post a couple of days ago about Genetically Engineered Yeast, Chaz from Alaskan Brewing sent me a link to an interesting blog post by Dmitri, an amateur yeast wrangler who writes about his yeasty adventures at BKYeast. The post is a review of science literature from Cerevisia, the Belgian Journal of Brewing and Biotechnology. The article in question is titled Selecting and Generating Superior Yeasts for the Brewing Industry, which was published in 2012. It’s deliciously geeky and technical, but should be scrutable to anyone who brews either professionally or at home, thanks to Dmitri’s writing, as his goal is to take the jargon and science and make it accessible to a broader audience. As brewers struggle to have their beers stand out in an ever-increasingly crowded marketplace, it should be obvious that we’ll be seeing more and more experimentation with flavors and ingredients and ultimately more unique beers, and even new types of beers as others copy the successful ones, in the coming years. As the author notes, new varieties of hops are already facilitating that effort, and it seems likely that new strains of yeast are a logical next step in that evolution. And that’s what this research by a group from Leuven, Belgium is trying to make easier, finding the right yeast to create the right range of flavors for your beer. Give it a read.
“Graphical representation (heat map) of different characteristics of industrial yeast strains. Every row consists of data from a different yeast strain, every column is a different characteristic. ‘Yellow’ is a low score, and ‘red’ is a high score for this certain characteristic. The dendrogram on the left represents the genetic relatedness of the yeasts, based on an AFLP fingerprint exploiting transposon TY1 insertion site polymorphisms. The colour code on the top right indicates the origin of the yeast strains. This kind of analysis allows us to select yeasts with specific beneficial traits, for example to use in industry, or for breeding.”
Mashable had an interesting piece about Genetically Engineered Yeast being done by at least two companines, Amyris and Evolva, and based in part on a New York Times article, What’s That Smell? Exotic Scents Made From Re-engineered Yeast. In the Times article Amyris co-founder Jay Keasling explained “that the process is ‘just like brewing beer, but rather than spit out alcohol, the yeast spits out these products.'” The relatively new discipline, dubbed synthetic biology, is only about a decade old. There are apparently issues about whether it would be considered natural. SOme say no, because the synthetic version “contains scores of components besides” what it’s being used as, while John B. Hallagan, from the Flavor and Extract Manufacturers Association believes “it conceivably could be called a natural ingredient since it is made in a living organism.”