The effect of the temperature (25 and 35 degrees C), the hydraulic retention time, HRT, (12 and 24 h) and initial substrate concentration on hydrogen production from Tequila vinasse was studied using a sequencing batch reactor. When 25 degrees C and 12-h HRT were applied, only insignificant biogas quantities were produced: however, using 24 h of HRT and temperatures of 25 and 35 degrees C, biogas containing hydrogen was produced. A maximum volumetric hydrogen production rate of 50.5 mL H(2)L(-1) H(2)L(-1) (48 mmol H(2) L(reactor)(-1) d(-1)) and an average hydrogen content in the biogas of 29.2 +/- 8.8% were obtained when the reactor was fed with 3 g COD L(-1), at 35 degrees C and 12-h HRT. Methane formation was observed when the longer HRT was applied. Results demonstrated the feasibility to produce hydrogen from this waste without a previous pre-treatment. (C) 2010 Elsevier Ltd. All rights reserved.