The growing demand for sustainable, plant-based, and health-promoting beverages has revived interest in grain-based coffee alternatives, valued for their caffeine-free profile and nutritional attributes. Derived from roasted grains and legumes (e.g. barley, rye, wheat and chicory), these align with sustainability goals due to low agricultural input requirements and reliance on locally sourced materials. Meanwhile, grain-based coffee products provide bioactive compounds (e.g. dietary fiber, polyphenols and fermentable carbohydrates), which may support gut health and glycemic regulation. Given the key role of carbohydrates in influencing both sensory properties and nutritional value, this study focused on characterizing the carbohydrate composition of a wide range of commercial grain-based coffee products, with an emphasis on the quantification of low-molecular-weight soluble carbohydrates. Analytical determinations were performed using high-performance liquid chromatography with refractive index detection. The results revealed significant heterogeneity in carbohydrate profiles; arabinose, fructose, glucose, sucrose and maltose were present in various concentrations, with total carbohydrates ranging from 0.60 to 10.42% depending on formulation. Products formulated with blends of multiple grains exhibited higher diversity in sugar composition compared to single-source variants. Variations in carbohydrate concentrations were attributed to differences in raw material composition as well as thermal processing conditions. These results highlight carbohydrate profiling as a valuable tool in differentiating grain-based coffee products not only for quality control but also for the development of functional beverages tailored to health-conscious consumers. Moreover, this work contributes to the growing body of knowledge on the nutritional properties of plant-based beverage alternatives. The identified carbohydrate patterns have implications for both nutritional labeling and the development of functional beverages with targeted health benefits, particularly in relation to gut microbiota modulation and glycemic response; these insights support the positioning of grain-based coffee products as sustainable, functional alternatives in the health-oriented and environmentally conscious food systems.