The effects of sugar concentration and mineral addition on the growth of Aspergillus carbonarius in carob solid state fermentation were studied. Data on CO2 production, sugar levels and tannins levels, and optical observations, revealed when carob husk with additional mineral salts was used as a substrate, this led to high biomass production. On the other hand, removal of 52% of the water-soluble sugars, prior to fermentation, and elimination of the minerals resulted in a tannin degradation up to 55%, but poor biomass production.