Happy #NationalLagerDay!
*This is an updated/modified essay previously posted here on 2021-12-10*
The world knows the word Lager and here in the US, we seem to think of Lager as the straw-colored, mass-market beer. Nothing inherently wrong with those Lagerbier styles, by the way. The difference between Ale and Lager is not as much as one would think, but the only physical difference is the yeast. The history of Lager is complex, and yeast has the most important role in it. While the place where Lagerbier originated may be surprising to some and obvious to others, I’m sure there are some surprising yeasty facts below for either camp. I’ll make this as brief as possible.
Grab a Lagerbier and let’s go back in time.
A good starting point is the enactment of the Reinheitsgebot. On April 23rd, 1516, Duke of Bavaria, Wilheim IV, a member of the royal Wittelsbach family, decreed what will eventually be the longest still-standing brewing standard we now refer to as the German Purity Law. Although beer was not the focus of the decree (more about it here), it can be argued that it did lay the foundation for Lagerbier with the restriction of ingredients. As we all know, the original proclamation specifically calls out for water, hops, and malt to be used in Bavarian beer. No yeast was mentioned, but this was fantastic news for our hungry little fungi friends. More on that later.
Mother Nature assisted in Lageriber’s firm grip in Bavaria before the next proclamation. Climatologists agree that a “Little Ice Age” began no later than 1550 and dropped the average temperatures by a degree or so. It may sound insignificant, but it was enough to be noticed all over Europe until temperatures stabilized around 1850.
In 1553, Wilheim’s successor and son, Duke Albrecht V, outlawed brewing in the summer months due to the inconsistent beers being produced during these warmer months. The dates Albrecht chose were April 23rd, the original date of his father’s proclamation, to September 29th. They didn't understand why, yet they knew fermentation and cold storage (“Lagern,” German verb “to store”) done in the colder months of the year resulted in higher quality beers.
The Munich Dunkel Lagerbier's origin as a beer style can be traced back to these events. Malts were darker in color, the water chemistry high bicarbonates (alkalinity) to aid in dark beer production, and proclamations to keep beers cold for an extended period. Munich Dunkel has been cited many times as not only the first beer style to be designated, but as the first Lageriber to be named as such. Lager yeast helped in many ways here. Cold storage for ideal fermentation temperatures, little to no fermentation characters, and extended lagering to promote clarity and round flavors.
Note: Kräusen is the fluffy stuff that develops at the top of the fermenter that is made up of yeast and proteins and other materials frothed up because of yeast metabolism.
After identifying S. cerevisiae as a hybridization parent of S. pastorianus, it was thought that the likely candidates were S. uvarum or S. bayanus might fit the bill. It turns out S. uvarum is a pure landrace to the region that is not hybridized and S. bayanus is hybridized from S. cerevisiae, S. uvarum, and another strain. We know S. bayanus by its more common name, Champagne yeast. After evaluating over 1,000 other European strains, it was later determined that S. pastorianus’ parent is not from Europe!
In 2011, microbiologists took their search for the origin of S. pastorianus to Patagonia, between Chile and Argentina in the high Andes. It’s cold there and that’s important. Many yeasts were collected and studied from there. One was found to be unidentified and was sent to Colorado for sequencing while the team on-site determined this strain was a pure landrace.
Then, it happened…. When the DNA was sequenced in Colorado, the yeast’s genome was found to be over 99% the same as the non-S. cerevisiae portion of the S. pastorianus segment.
Then, it happened…. When the DNA was sequenced in Colorado, the yeast’s genome was found to be over 99% the same as the non-S. cerevisiae portion of the S. pastorianus segment.
In the words of Murry…. “You ARE the father!” And it was a busy father, indeed. S. eubayanus, as it would be named, was also the missing sequence for S. bayanus. It is still not understood how S. eubayanus got from South America to Europe, although there are many fun ideas such as on a bird. There is ongoing research, including the discovery of S. eubayanus elsewhere in South America, North America, China, Tibet, New Zealand, and a recent find of it in Ireland. There is at least a more solid understanding of the genetics that helped us identify the full origin of the yeast that made Lagerbier!
A toast to the reason for our little single-celled organism that makes our favorite drink. It is because of Lager yeast, along with serendipitous events and lucky molecular hybridization, that we have Lagerbier to enjoy today. I’ll see you all out there for a Lagerbier.
Prost!
-Gilbert "Charlie" Perez, Advanced Cicerone®
References
Sean A Bergin, Stephen Allen, Conor Hession, Eoin Ó Cinnéide, Adam Ryan, Kevin P Byrne, Tadhg Ó Cróinín, Kenneth H Wolfe, Geraldine Butler (2022). Identification of European isolates of the lager yeast parent Saccharomyces eubayanus. Oxford University Press on behalf of FEMS. https://academic.oup.com/femsyr/article/22/1/foac053/6874782
Alworth, J. (2015, 2021). The Beer Bible. Workman.
Dornbusch, H. D. (1997). Prost! The Story of German Beer. Brewers Publications (Brewers Association).
Kraus-Weyermann, T., Dornbusch, H. D. (2018). Dark Lagers: History, Mystery, Brewing Techniques, Recipes. Master Brewers Associations of the Americas (MBAA).
Oliver, G. (2012). The Oxford Companion to Beer. Oxford University Press.
Oliver, G. (2012). The Oxford Companion to Beer. Oxford University Press.