Yosha and Philu are traditional fermented yak milk products produced by communities in the highlands of Bhutan. The study aimed to document their traditional production methods and to characterize their nutritional profile using qualitative and quantitative approaches, including field observations, interviews with local producers, photographic documentation of the processing stages, and compositional analysis. Two production methods were identified for Yosha: one based on natural fermentation using a back-slopping technique, and another that uses whey from the previous batch for coagulation during heating, followed by ripening of the curd in animal skin. Philu, which has a creamy texture, is traditionally produced using birch or willow branches. During six months of ripening, Yosha showed significant changes (p ≤ 0.05) in total solids, protein, ash, pH, and titratable acidity, while the increase in fat content was not statistically significant. Philu exhibited a significantly higher moisture content and moderate levels of protein, fat, ash, and pH. Statistical differences between Philu and Yosha, both fresh and ripened, were significant for all parameters. These findings demonstrate the influence of fermentation and ripening on the nutritional profile and highlight the cultural and artisanal value of these products, while underscoring the need for further studies on their microbial and sensory characteristics.
Nair et al. (2026) studied this question.