Tella (Ethiopian traditional beer): brewing, microbiology, nutrition, health implications, byproducts, and challenges

Tella, Ethiopia’s traditional cereal-based beer, is produced at an estimated national scale of 8 million hL per year, yet no prior systematic review has synthesized its microbial ecology, nutritional attributes and commercialization potential. This study presents the first systematic synthesis of 73 peer-reviewed studies complemented by primary ethnographic interviews with 42 brewers across 6 regions. Findings reveal that Atella (the fermentation residue) contains crude protein 16.5–24.2% DM, pH 3.36–4.23, and serves as a low-cost feed supplement. Dominant lactic acid bacteria (LAB ≥107 CFU mL−1) and yeasts (Saccharomyces, Candida and Lactobacillus) drive fermentation, producing beverages with ABV 3–9% v/v and pH 3–5. Pasteurization combined with vacuum filtration extends shelf life from 5–7 days to ≈14 days an increase of ≈300%. Physicochemical and microbial variability across regions reflects process diversity but also opportunity for standardization. Three barriers limit wider adoption: (1) heterogeneity of household production, (2) short shelf life and safety inconsistency and (3) limited regulatory and market integration. To overcome these, an eight-point commercialization roadmap is proposed: standardized starter cultures, HACCP-based micro-breweries, Atella grading for feed markets, women-led cooperatives, cost modeling, regulatory engagement, packaging innovation and sensory evaluation. This review bridges traditional knowledge and scientific insight, positioning Tella and Atella as culturally rooted yet economically viable products for sustainable rural development and future functional-food innovation.