Effect of some unconventional ingredients on the production of black beer

Abstract

Introduction. The aim of this research is to determine the effect of some unconventional ingredients such as the acorn flour, topinambur flour and molasses in order to develop a beverage similar to black beer. Materials and methods. Black beer was obtained according to a conventional method of obtaining beer in a pilot scale brewery. In the manufacturing recipe, brown malt has been replaced with acorn flour, topinambur flour and molasses with 50% sucrose in the following variants: variant 1 0.5:1.5:1; variant 2 1:1:1; variant 3-1:1.5:0.5; variant 4 1.25:1.25:0.5. For fermentation of bottomfermenting yeast was used. The extract content, alcohol content and apparent fermentation for the black beer samples were analysed with the Anton Paar device. Results and discussion. The CO2 content, foam height, foam stability, total acidity of beer, for all the analyzed samples are within the admitted limits for the black beers. The sensory characteristics of the black beer samples evaluated, namely appearance, colour, odour, taste, gas release and foam stability indicates the fact that the variant 1 of the black beer received the lowest score whereas the variant 4 received the highest one. The sensory analysis results were unexpected ones, the non gluten beers obtained being very well appreciated, the panellists preferring them over commercial black beers made from traditional ingredients. The black beer obtained in all four experimental versions are beers with an alcoholic concentration which ranged between 7.06% and 8.16%, with a high degree of final fermentation, which ranged between 73.26% for variant 2 and 85.85% for variant 4. The data obtained with the unconventional raw materials as the acorn flour, topinambur flour and molasses were comparable to commercial black beer, which acted as the control sample. The best result regarding the final fermentation degree (85.85%) was obtained for the variant 4, even higher than those obtained for the commercial beer (80.20%). Also, the variant 4 was the best appreciated from the sensory point of view. This variant can be proposed to obtain black beer on an industrial scale because it has good physico-chemical properties comparable to a black beer on the market. Conclusions. Black beer, obtained on the basis of an innovative manufacturing recipe, presented good sensorial characteristics, a freshly roasted coffee flavour, a fruity taste and bittersweet.