Author ORCID Identifier:
Date of Graduation
5-2026
Document Type
Thesis
Degree Name
Master of Science in Food Science (MS)
Degree Level
Graduate
Department
Food Science
Advisor/Mentor
Lafontaine, Scott
Committee Member
Guzman, Christian
Second Committee Member
Atungulu, Griffiths
Keywords
Adjuncts; Amylose; Brewing; Rice
Abstract
Rice (Oryza sativa L.) presents a locally sourced, climate-resistant starch source for the brewing industry. As barley faces increased uncertainty due to rising temperatures, Arkansas-grown rice offers a more stable and cost-effective alternative starch source. However, the use of milled adjunct rice by brewers has remained limited, largely due to knowledge gaps about cultivar-specific properties relative to brewing. Chapter 1 provides an overview of rice as a brewing adjunct, reviewing the physiochemical properties important to brewing success. These properties include kernel size, kernel breakage, amylose content, and gelatinization temperature. Mashing strategies for multiple different brewing layouts are overviewed, showing practical approaches to utilizing rice as an adjunct when the cultivar's physiochemical parameters are known. Chapter 2 provides an evaluation of 74 unique rice cultivars to identify what factors are most associated with extract yield. Extract yield showed a statistically significant difference between different rice cultivars, showing that extract yield is related to the cultivar. Contrary to previous research, kernel size was not shown to be a good predictor of extract yield. However, cultivars with lower amylose content were shown to have a higher propensity to fractionate into smaller particles during cyclone milling, which consistently yielded higher extract. Showing the importance of breeding decisions and milling decisions to further optimize brewhouse performance. Chapter 3 investigates the brewing implications that are linked to agricultural and post-harvest decisions, harvest moisture content, and post-harvest aging. Four Arkansas-grown cultivars harvested across 5 harvest moisture contents were evaluated for head rice yield, extract yield, particle size distribution, gelatinization temperature, and amylose content. Extract yield peaked at 18%, showing that extract and head rice yield appear to have conflicting optimal harvest moisture contents. Most notably from this study, aging of the paddy rice showed statistically significant increases in extract yield and a shift to smaller particle size. Overall, this work shows a technical and agricultural approach to improving the characteristics most optimal for utilizing milled rice as a brewing adjunct. Closer collaboration between rice breeders, producers, and brewers will be essential to fully optimize rice as a brewing adjunct.
Citation
Aitkens, M. (2026). Unveiling Factors Influencing Extract Yield from Milled Rice in Brewing. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/6265
