Bypassing the Malting Process with Koji

Tom Williams, Dr. Brett Taubman, A.R. Smith Department of Chemistry and Fermentation Sciences, Appalachian State University, 287 Rivers St, Boone, NC 28608

Barley is an important ingredient in the production of beer and other grained-based beverages, contributing fermentable sugars, flavor, and aroma. For barley to be of use in the brewing process, enzymes that break down starches in grain must be accessible in order to develop a medium that yeast can ferment. These enzymes are activated via the malting process, which takes between 9-11 days, and consumes up to 1,140 gallons of water and 800kWh of energy on an industrial scale. Aspergillus oryzae is a filamentous fungi used in the production of many Asian foods and beverages where it is used to saccharify a host of substrates. In addition to enzyme production, it yields unique flavors and aromas not found in traditional malted barley. The goal of this research was to determine if A. oryzae, commonly referred to as Koji, can be used on unmalted barley to bypass the malting process and produce fermented beverages comparable to those that use malted barley. This research also set out to quantify and characterize the organoleptic and sensory characteristics in a beverage produced using Koji barley. It was predicted that Koji barley would produce an appreciable level of enzyme activity as well as a host of sensory characteristics. To test this, pearled barley was inoculated with different strains of A. oryzae and saccharified using a mash test to determine its yield of enzymes and soluble sugars in beer wort. This wort was fermented with standard brewer’s yeast and its attenuation and ethanol content were quantified. The presence of organic acids and other compounds in the fermented wort were then quantified using HPLC. Finally, a sensory analysis was conducted to characterize its flavors and aromas. The results supported the prediction and demonstrated new potential applications for Koji barley in the brewing industry. 

Additional Abstract Information

Presenter: Tom Williams

Institution: Appalachian State University

Type: Oral

Subject: Chemistry

Status: Approved

Time and Location

Session: Oral 7
Date/Time: Tue 3:30pm-4:30pm
Session Number: 710
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