Recirculation of treated effluent is usually used to prevent organic overloading events in anaerobic digestion of high concentrated wastewater. The aim of this study was to determine the influence of effluent recirculation in anaerobic baffled reactors (ABR) treating high concentrated wastewater as the literature is not conclusive about its effects. To achieve this, an innovative experimental and mathematical modeling dual approach was used. A bench-scale ABR was fed with sugarcane vinasse (COD = 18.0 g L⁻¹) and monitored for 273 days. Real kinetic and mass transfer parameters were obtained and used to create a mathematical model for the organic matter conversion. Operating data and the kinetic parameters showed that at high COD concentrations the ABR does not behave as a two-stage system as expected. Both results, i.e. the mathematical model and the operational data, showed that in terms of conversion capacity using high recirculation ratios is not necessary for suitable ABR performances, only increasing operational costs due to pumping.