Only a handful of ingredients are needed to brew beer. A brewer needs water, hops, malt and yeast. While each of these is a vital ingredient, yeast is perhaps the most important. Without yeast, there would be no way to transform the sugars from the malt into alcohol – you’d be left with a strange tasting mixture with no alcohol content. Really, it’s yeast that makes beer… well, beer!
Quite a variety of yeasts are used to brew different types of beer, from dry wine type yeasts to ale yeasts. Different strains have different characteristics and affect the finished product in diverse ways. Modern beer yeasts are well quantified and categorized according to their ideal brewing purposes, but they all began with an original wild strain.
A Significant Difference in Yeast Strains
While all yeasts are pretty similar in the way they work (they all convert sugar into alcohol), they are not all created equal. Some yeast is able to withstand higher concentrations of alcohol and can produce stronger brews. Many yeast strains are temperature sensitive as well. Often, brewing requires keeping the batch within a specific temperature range or risking killing those all-important yeast cultures.
One mystery that has baffled scientists for a very long time is the identity of the yeast first used to cold-brew ale to create lager. While modern yeasts are available in abundance, no one seemed to be able to locate the original wild strain that enabled ancient European brewers to produce higher alcohol content beer at colder temperatures. That mystery was recently solved.
European Brewing Yeast Discovered Lurking in South American Forest
It looks like part of the difficulty in locating the ancestor of today’s cold-brewing yeast was that scientists were looking in the wrong place. They were (rather logically) looking in Europe, which is where the yeast was supposed to have originated. However, they had no luck in locating it even though they scanned the DNA of more than 1,000 yeast species. A little global cooperation helped here, though.
Lurking within the forests of Patagonia, scientists seem to have located the missing yeast strain. It’s a wild variety that can be found in prevalence throughout the area and seems to make its presence best known by flourishing within galls on plants (abscesses caused by insects laying their eggs on the plant). The yeast ferments within these galls, and the smell of ethanol is prevalent when the galls fall to the forest floor and rupture.
With a little scientific study and some genome research, scientists found that this particular strain was the best fit for the missing European variety. The discovery has inspired scientists in other areas of the world to redouble their efforts to locate the variety in the wild elsewhere.
How Did It Travel from Europe to South America?
The next question scientists had to answer was what was the yeast doing half a world away from where it was supposed to be? If the yeast originated in Europe, what was it doing hiding in the South American forest? The answer to this question seems to be colonization and international trade.
Cross-contamination of foreign species is nothing new or unknown to science. History is rife with examples of nonnative plants and animals making their way into new ecosystems with the help of humans, and it seems that this yeast had similar assistance. Speculation is that the yeast made the Atlantic crossing in a fruit fly or even on a piece of wood once European explorers began visiting South America for colonization and trade. From that point, the yeast made its way into the forest and has been thriving ever since.
Why Does It Matter?
For most people, the logical question here is, “Why does it matter?” After all, if we have modern varieties of yeast capable of cold-brewing beer then what’s the big deal with finding the ancestor to those strains? Actually, there are several reasons why it matters.
Historic Significance: One reason that scientists have been so keen to locate this yeast (the search has been ongoing for decades) is for the insight that it could provide on early brewing. Originally, it was used in caves within Bavaria, where it was used to create the world’s first cold-brewed beer. This insight offers a great deal of information about brewing conditions, requirements and more, helping us understand just what our own ancestors had to do to brew their beer.
Potential New Hybrids: Another reason that the discovery of this yeast is so important is that it could eventually lead to the development of different yeast strains. The benefits involved might include better cold resistance, higher alcohol resistance, better longevity, different flavor characteristics and much more. It’s an exciting prospect, though it will take years for any developments to come from the research.
Using the Original: Finally, for those brewers who truly want to go back to the roots of brewing, there’s always the possibility that the wild yeast will be domesticated and released through brewing supply companies as specialty yeast. That would give brewers the ability to use a yeast strain that has not been seen in the brewing world for centuries and offers a direct connection with the past.
Of course, it will take quite some time for scientists to do their work and for any developments to come about. In the meantime, brewers have access to quite a range of yeasts descended from those ancient organisms, all of which are capable of allowing cold brewing. So, if you find yourself antsy about getting your hands on the original strain, you’ll have to content yourself with the options available, at least for now. The good news is that modern yeast provides far more reliable results than wild yeast so while you might not have the immediate connection to ancient brewing practices that you want, you can at least be content in knowing that you’ll have better luck than many brewers in the past.