The demand for lactic acid as a raw material for the chemical industry is on the rise. Various lactic acid bacteria (LAB) have been tested for the fermentation of sugar-cane juice and molasses into lactic acid. Industrially, the most commonly used producer strains are from the Lactobacillus genus. We report here on the fermentation of sugar-cane juice and syrup into L-lactic acid using Lactobacillus delbrueckii subsp delbrueckii (NCIM 2365). We present a reliable method to quantitatively assess the amount of L-lactic acid produced during fermentation using 1H NMR spectroscopy. This analytical method offers various advantages over existing ones and can be extended to the on-line monitoring of fermentation of sugars into lactic acid in industry.