EFFECTS OF BREWING TECHNIQUE AND PARTICLES SIZE OF GROUND RICE ON A SENSORY PROFILING OF BREWED SAKE BEER

Abstract

The effect of brewing techniques and particle size of malted rice on the sensory profile of brewed sake beer was investigated. Rice grains were purchased, analysed (grain analysis) and malted. The malts were divided into four equal parts and labelled A, B, C and D. Sample A was finely milled, Sample B was coarsely milled, Sample C was roughly milled while sample D was rough coarsely milled followed by malt analysis. Infusion mashing technique with the aid of exogenous enzymes (α-amylase, β-amylase, β-glucanase and proteinase) were used to obtain worts of varying concentrations. The worts obtained were analyzed, boiled with hops for 1¹/₂ hour and pitched with yeast strain Saccharomyces cerevisiae to commence primary fermentation for 7 days followed by secondary fermentation for 14 days. The resulting beer were analysed for their physicochemical properties. The results of wort analysis showed original gravity, sugar level, pH, flow rate, and viscosity of 1.027⁰ρ, 6.82⁰Brix, 5.49, 18.50 sec and 1.04cp for sample produced from finely milled grist. Sample produced from coarsely milled grist showed original gravity, sugar level, pH, flow rate, and viscosity of 1.031⁰ρ, 7.8⁰Brix, 5.58, 18.45 sec and 1.04cp. Sample produced from roughly milled grist showed original gravity, sugar level, pH, flow rate, and viscosity of 1.031⁰ρ, 7.8⁰Brix, 5.62, 18.68 sec and 1.05cp. Sample produced from roughly milled grist showed original gravity, sugar level, pH, flow rate, and viscosity of 1.028⁰ρ, 7.06⁰Brix, 5.57, 18.48 sec and 1.04cp. The specific gravity of the beer samples ranged from 1.001 to 1.002⁰ρ, sugar (0.26–0.52^oBrix) and alcohol (2.35–2.87)%v/v. There was no significant difference regarding the sensory properties (colour, taste, mouth feel and general acceptability) of the sake beer produced from finely milled, coarsely milled, roughly milled and roughly coarsely milled particle sizes. The result of this investigation revealed that for the malted rice studied, the proportion of the particle with that the best brewing result in terms of extract content, filtration, fermentability and sensory profile, are malts that are coarsely and roughly milled