The high-altitude brewery
In the high-altitude cold desert of Ladakh, traditional fermented beverages are a staple of the local diet. At elevations around 3,500 meters, communities prepare drinks like Chhang and Lugri, often made from barley or rice. These beverages are culturally significant and they are complex ecosystems with microorganisms. The fermentation process relies on a starter culture, locally known as 'phab', which contains a mixture of lactic acid bacteria (LAB), yeasts, and molds. This process happens under extreme environmental conditions: intense ultraviolet (UV) radiation, low oxygen levels, and drastic temperature fluctuations. These stressors have shaped the evolution of the microbial communities, resulting in unique strains adapted to survive where others cannot.
The dominant microbes responsible for the fermentation include yeasts like Saccharomyces cerevisiae and various species of Lactic Acid Bacteria such as Lactobacillus and Leuconostoc. These organisms are responsible for producing the alcohol and characteristic acidic flavors of the beverages. The specific composition of the microbiome varies, influenced by the grain used (rice, wheat, or barley) and the specific preparation techniques passed down through generations. For example, rice-based lugri often has a higher alcohol content and different microbial populations compared to its barley-based counterpart. This natural laboratory at high altitude has produced a reservoir of extremophilic microbes with unusual biochemical capabilities.