Journal of Industrial Microbiology

, Volume 10, Issue 1, pp 61–68

Production of 21% (v/v) ethanol by fermentation of very high gravity (VHG) wheat mashes

  • K. C. Thomas
  • W. M. Ingledew

DOI: 10.1007/BF01583635

Cite this article as:
Thomas, K.C. & Ingledew, W.M. Journal of Industrial Microbiology (1992) 10: 61. doi:10.1007/BF01583635


Very high gravity wheat mashes containing 300 g or more sugares per liter were prepared by enzymatic hydrolysis of starch and fermented with a commercial preparation of active dry yeast. The active dry yeast used in this study was a blend of several strains ofSaccharomyces cerevisiae. The fermentation was carried out at 20°C at different pitching rates (inoculation levels) with and without the addition of yeast extract as nutrient supplement. At a pitching rate of 76 million cells per g of mash an ethanol yield of 20.4% (v/v) was obtained. To achieve this yeast extract must be added to the wheat mash as nutrient supplement. When the pitching rate was raised to 750 million cells per g of mash, the ethanol yield increased to 21.5% (v/v) and no nutrient supplement was required. The efficiency of conversion of sugar to ethanol was 97.6% at the highest pitching rate. This declined slightly with decreasing pitching rate. A high proportion of yeast cells lost viability at high pitching rates. It is suggested that nutrients released from yeast cells that lost viability and lysed, contributed to the high yield of ethanol in the absence of any added nutrients.

Key words

Very high gravity Wheat mash fermentation Fuel alcohol High pitching rates 

Copyright information

© Society for Industrial Microbiology 1992

Authors and Affiliations

  • K. C. Thomas
    • 1
  • W. M. Ingledew
    • 1
  1. 1.Department of Applied Microbiology and Food ScienceUniversity of SaskatchewanSaskatoonCanada

Personalised recommendations