The Climate in Your Glass

The Beer That Breathes: An Introduction to Spontaneous Fermentation

Imagine a beer that captures the very essence of its environment—a complex brew that breathes with the local air, changes with the seasons, and tells the story of its origin in every sip.

This isn't the latest craft beer trend, but rather one of the oldest brewing traditions known to humanity: lambic beer. For centuries, Belgian brewers have harnessed wild yeasts and bacteria from the air around Brussels to create these unique spontaneously fermented beers. Now, in the unlikely setting of New Zealand's South Island, scientists are exploring how this ancient brewing tradition adapts to a new environment—and what it might reveal about how climate change is transforming our foods and beverages ^{1 6} .

Recent groundbreaking research from Lincoln University has examined lambic-style beers produced in Oamaru, New Zealand, uncovering fascinating connections between microbial populations, organic acid concentrations, and climatic variables ^{1 6} . This research provides not only a window into the intricate world of spontaneous fermentation but also a cautionary tale about how shifting climate patterns may affect these traditional processes, particularly in newer brewing regions attempting to establish their own terroir.

What Makes Lambic Beer So Special?

Unlike conventional beers that rely on carefully controlled yeast strains, lambic beer undergoes spontaneous fermentation through exposure to the open air. The wort (unfermented beer) is left in large, shallow containers called coolships overnight, where it collects wild yeasts and bacteria from the surrounding environment ^{1 6} . This complex microbial community then works together—and sometimes competes—over an extended aging period, typically one to three years in wooden barrels ⁶ .

The true heart of traditional lambic production lies in Belgium's Pajottenland region, surrounding the valley of the Zenne River southwest of Brussels. Similar to the concept of "terroir" in wine, this specific geographic area is believed to host a unique combination of microorganisms essential for proper lambic fermentation ⁶ . The particular environmental conditions—the temperature fluctuations, humidity levels, and even the architectural specifics of traditional brewery buildings—all contribute to creating the distinctive lambic character ¹ .

A Scientific Journey to New Zealand's Emerging Lambic Scene

In a pioneering study conducted from 2016 to 2022, researchers characterized the microbiome of 11 spontaneously fermented beers produced by a single brewery in Oamaru, New Zealand ^{1 6} . This longitudinal approach across multiple vintages allowed scientists to observe variations not just between years, but between individual brews produced within the same year.

The Oamaru region presents a fascinating case study—its climate is categorized as warm and temperate with "a considerable amount of rainfall even during months that typically experience dry weather" ⁶ . This contrasts sharply with the Belgian heartland of lambic production, raising questions about how different environmental conditions might shape the resulting beers.

The Living Landscape: Microbial Communities Revealed

The findings revealed that both bacterial and fungal populations varied considerably between vintages and even between individual brews produced in the same year (2020) ⁶ . This variability stands in stark contrast to the relatively stable microbial populations found in traditional Belgian lambic beers and similar Russian ales, despite those regions experiencing greater extremes of weather ⁶ .

This correlation provides compelling evidence that climate variables directly influence the microbial succession that occurs during spontaneous fermentation—a process crucial to developing the complex flavor profile of lambic beers.

The implications of these findings are significant: they suggest that newer production facilities, without the long-established microbial ecosystems of traditional Belgian breweries, may be more vulnerable to climatic fluctuations. The research speculates that this stability in traditional settings may result from centuries of environmental adaptation, creating a resilient microbial community that can withstand annual weather variations ⁶ .

Beyond Microbes: The Flavor Connection

The scientific investigation extended beyond merely identifying microbes to understanding how these microbial communities influence the final beer character through organic acid production. The researchers measured concentrations of several key organic acids, finding that L-malic acid, succinic acid, and L-lactic acid levels statistically differed from one vintage to another ⁶ .

Perhaps more importantly, ordination analyses revealed a correlation between the concentrations of certain organic acids and the microbial composition ⁶ . This connection helps explain how climate-induced shifts in microbial populations might directly alter the biochemical and organoleptic properties of the resulting beers.

Climate Change: A Cloudy Future for Spontaneous Fermentation?

The findings from the New Zealand lambic-style beer study raise important questions about the impact of climate change on traditional and emerging brewing regions. If newer facilities producing spontaneously fermented beers are more susceptible to climatic variations, what does this mean for their ability to establish consistent production methods and flavor profiles?

This challenge isn't limited to lambic-style beer production. A related technological development comes from Kirin Holdings, which has created a seedling cultivation technique that improves heat and drought tolerance in hops—another beer ingredient threatened by climate change ⁷ . Using Czech 'Saaz' and German 'Hersbrucker' varieties, their approach demonstrates how both traditional methods and innovative technologies may be necessary to address these challenges.

Conclusion: A Toast to Microbial Diversity

The investigation into New Zealand's lambic-style beers reveals much more than just the microbial composition of these particular beverages. It uncovers the delicate interplay between environment, microorganisms, and cultural traditions—a relationship that may be increasingly vulnerable in a changing climate.

What makes this research particularly compelling is how it bridges ancient brewing traditions with cutting-edge scientific techniques. DNA metabarcoding allows us to peer into the microbial world that earlier brewers understood only through repeated observation and experience. These scientific tools not only help us appreciate the complexity of spontaneous fermentation but may also provide insights to help new brewing regions navigate the challenges of establishing their own unique terroir.

As climate patterns continue to shift, understanding these microbial ecosystems becomes increasingly crucial—not just for preserving traditional brewing methods, but for supporting the emergence of new regional styles that can adapt to their environment. The next time you raise a glass of spontaneously fermented beer, consider the invisible world of microbes that created it, and the local climate that shaped their journey. In our warming world, the story of these microbial communities represents just one chapter in the much larger narrative of how climate change is transforming our relationship with food and drink.