The nutritional and functional characteristics of cereal and millets have been enhanced by fermentation technology and have proven to be a viable option for the cereal industry. The fermentation technique aids in increasing the nutrient content, viz., minerals, vitamins, proteins, phenolics and antinutritional compounds, as phytic acid degrades. The study aimed to investigate the appropriate fermentation technique for developing ethnic fermented sour beverages and standardize the product with improved shelf stability for industrial use. Neeragarams (an indigenous fermented rice product from the southern part of India) were prepared using Mapillai samba, and a notable and nutritious traditional rice variety of Tamil Nadu was taken (T1 - raw - unpolished, T2 - raw - polished, T3 - parboiled - unpolished and T4 - parboiled - polished) with added species such as onions, green chillies and curry leaves. The study observed that among four different treatments of neeragaram, T1 (raw rice - unpolished) was highly acceptable based on consumer acceptability with the sensory value of 9.0 higher nutritional characteristics viz., energy 68.29 Kcal, carbohydrates 11.15 %, protein 4.21 %, fiber 2.59 %, fat 0.93 %, iron 4.21 mg, potassium 181.7 mg, sodium 61.23 mg and zinc 2.32 mg per 100 ml of neeragaram. The developed product will be highly suitable for commercialization with improved shelf stability. Among the four treatments, raw (unpolished) neeragaram was highly acceptable with maximum retention of nutritional characteristics. The developed fermented sour beverages do not involve a high cost of production and earn good returns to entrepreneurs. The development of these fermented sour beverages using rice will increase the suitability for consumers and, in turn, improve persons with nutritional and functional status.