Indian artisanal sour buttermilk: composition, processing methods, and health potentials

Purpose Artisanal sour buttermilk is an integral part of traditional dairy practices on the Indian subcontinent and is produced through fermentation of whole milk and subsequent churning of curd to yield butter (makkhan) and clarified fat (ghee). This process generates 15–20 kg of artisanal buttermilk per kg of ghee, which is often discarded because of its low total solids (approximately 4%), high acidity (0.7%–1% lactic acid) and bulky nature. Despite these processing challenges, both Ayurveda and modern studies highlight its nutritional and therapeutic benefits, underscoring the need for scientific valorization. Design/methodology/approach This review consolidates the available knowledge on artisanal sour buttermilk, focusing on its production methods, compositional attributes and functional potential. Special emphasis is placed on identifying technological gaps that hinder its preservation and utilization. Findings Artisanal sour buttermilk remains underutilized in the unorganized dairy sector, primarily because of its fragile composition and lack of standardized processing methods. However, evidence supports its role as a probiotic-rich, easily digestible beverage with potential health-promoting properties. Scientific interventions such as membrane processing and spray drying offer promising avenues to transform this byproduct into stable, value-added ingredients. The review concludes that systematic research and technological innovation can convert artisanal sour buttermilk from a neglected byproduct into a sustainable dairy resource, contributing to both rural livelihoods and a circular economy. Originality/value By examining traditional practices alongside contemporary scientific interventions, this review explores opportunities for improving process efficiency, enhancing product stability and expanding applications in functional dairy formulations.