A method for determining quality of biomass feedstock for production of ethanol and other biobased chemicals has previously been developed. The method is based on a model for forage utilization by ruminant animals, which partitions the carbohydrate fraction (non-structural and structural carbohydrates) of the biomass into three groups: soluble carbohydrates, carbohydrates available for digestion, including a rate constant for their availability, and carbohydrates unavailable for digestion because of their close association with lignin. A combination of compositional analysis and fermentation procedures were used to determine these parameters for four candidate biomass feedstocks. By using a commercial filter bag system in a batch processing mode, high throughput determination of the model coefficients is possible. This model can be used to assess quality of candidate biomass crop species, evaluate cultivation and genetic improvements in lignocellulosic crop, and analyze pretreatment technologies. In this experiment, this model was validated for comparison of a range of potential biomass feedstock species including cool and warm season grasses, high-fiber dicotyledons, and deciduous and coniferous tree species.