Black grapes (Vitis vinifera) and mahua (Madhuca longfolia) extract was used in 90:10 grape-mahua ratio for fermentation for 15 days and subjected to clarification using bentonite and gelatin as fining agents. Ageing was allowed for three months and studies were conducted using response surface methodology to assess the effect of ethanol, glycerol and temperature on viscosity, color, specific gravity, pH and overall acceptability. Experimental designs were conducted and 20 samples were prepared containing varying concentration of ethanol (7.55%-13.44%), glycerol (6.19-18.8g/l) and temperature (5.6-22.4oC) respectively. The maximum desirability of 93% was obtained for wine under the optimized conditions 13.44% ethanol, 6.19g/l glycerol and 14oC temperature, having viscosity (efflux time), 12.9 s; color absorbance, 4.61; SG, 1.0012; pH, 3.34 and overall acceptability, 8.47.
Ethanol, glycerol, mahua, optimization, quality, red wine