The cocoyam, Xanthosoma sagittifollium, as a potential raw material source for beer brewing

A widely cultivated cocoyam variety, Xanthosoma sagittifollium, was assessed for its suitability for lager beer production, using malted Sorghum vulgare (white variety) for saccharification of the substrate. The three-mash decoction method was used. Results showed that the cocoyam was superior to barley and sorghum as a substrate because of its potentially higher carbohydrate content (71-78%) compared to barley (65%) and sorghum (70-73%). The percentage wort extract was 13.3-14.5 degrees plato compared to 7-12 for barley and 13 degrees for the tuber crop, cassava. The kiln dried Xanthosoma sagittifollium gave a dark bager beer with good aroma (68%) and very good flavour (73%) when compared with a commercial lager beer (Monarch) as standard (100%). The alcohol content (4.16% w/v) and the specific gravity (1013) were within the range (4.0-6.4%) and (1011-1019), respectively, specified by the Standard Organization of Nigeria. Although the bitterness value 40 EBU, was higher than the typical range 16-30 EBU, the taste panel indicated this was acceptable. The pH was 4.68 compared with the standard 4.36, while the acidity (as % lactic acid) was 0.36 compared to 0.24 for some commercial products.