Date on Master's Thesis/Doctoral Dissertation

12-2008

Document Type

Master's Thesis

Degree Name

M. Eng.

Department

Chemical Engineering

Committee Chair

Berson, Robert E. (Eric)

Subject

Alcohol; Distillation; Alcoholic beverages; Corn--Utilization; Whiskey industry

Abstract

In the whisky industry there is a balance between the desire to adhere to the traditional production process and the desire to increase profit margins. One solution that follows both stipulations is to increase the alcohol yield of a given batch of whisky. This can be achieved by utilizing high total fermentable corn which has a higher concentration of fermentable starches than other corn. HTF corn has the potential for a greater final ethanol yield. By simply using a higher quality of raw materials, the integrity of the process is maintained while allowing for an increase in output. Ten strains of HTF corn (35D28, 35Y33, 34M94, 32K33, 34P88, 33A84, 34H31, 31G66, 33N56, and 34A15) and four strains of control corn (33N09, 32W86, 33M54, and 34D71) were tested for mash pH, sugar content by mass (balling), conversion of starch to sugar, conversion of sugar to ethanol, and alcohol content by volume (ABV). Ten trials were performed using HTF corn, yielding 60 fermentations; 18 trials were performed using control corn, yielding 158 fermentations. Each trial yielded five to nine fermentations depending on the size of the cooks. Due to contamination from an unknown source, only 44 HTF and 41 control fermentations were clean and, therefore, were used to establish the most significant trends. For a 99% confidence level, a clean HTF fermentation yielded 9.69% ± 0.14% ABV and a clean control fermentation yielded 9.34% ± 0.08% ABV. From these values it was determined that the HTF corn provides a 3.6% increase in alcohol yield over control corn. This indicates that the HTF corn may provide an advantage over the control corn when moved to an industrial scale. When the strains of corn were compared on an individual basis, HTF strain 32K22 appeared to be the strain of choice for whisky production at this preliminary stage. Strain 32K22 provided for the highest levels of conversion of both starch and sugar, at 97.6% and 98.3% respectively, and it produced the highest alcohol content of any strain at 10.42% ABV. The 32K22 strain achieved an overall conversion of starch to ethanol of 95.9% which is significantly higher than the average overall conversion for the control corn, 88.5%.

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