Flame spectroscopy is a technique widely used to analyze combustion processes.In a flame, energy is emitted across a wide spectral range, and its corresponding spectra can be classified in both, continuous and discontinuous behaviors. Optimizing combustion, has the potential to maximize efficiency, thus reducing fuel consumption and emissions of residual gases. This report shows the spectral emission of a flame emitted by combustion of pellets at different humidity contents, from a specific brand (here referred to as Alfa), typical in the Chilean market. To perform the spectral analysis, the HR-4000 spectrophotometer (Ocean Optics), previously calibrated in absolute radiance (in uW/nm·cm2) was used. From the collected spectra, parameters such as flame temperature (in °C), total continuous radiation (in μW/cm2) and total continuous energy (in μJ) were estimated. The spectral behavior, at different humidity contents, shown different spectral patterns. Thus, in this report we introduce the optical calorific power (in J/kg), quantifying the energy provided by a pellet sample, and calculated from spectral results. For the Alfa brand, with a humidity content between a 6-8% we estimated an optical calorific power of 6.12 (J/kg) and with a humidity content of 13.6 %, an optical calorific power of 4.96 (J/kg). The different parameters proposed in this work hold promises for understanding biomass combustion phenomena, such as the dynamics of energy emission in flame distribution.