Comparisons of Modern U. S. and Canadian Malting Barley Cultivars with Those from Pre-Prohibition: III. Wort Sugar Production during Mashing

ABSTRACT

Wort sugars produced during Congress mashing of pre-Prohibition and modern barley genotypes were compared. Four of five modern cultivars were higher (P < 0.0001) in wort glucose production than six pre-Prohibition cultivars. Mean wort glucose levels of the five modern cultivars were higher (P values from 0.0002 to 0.0021) than that of the pre-Prohibition barleys. In contrast, maltose production was variable and there were no significant differences in mean levels in modern versus pre-Prohibition barley worts, although Manchuria (pre-Prohibition) and Tradition (modern) produced higher (P < 0.0001) levels than other genotypes. Wort maltotriose levels were also quite variable among genotypes, although were higher (P < 0.0001) in Harrington (modern) worts than all others at the end of mashing. By the end of mashing, pre-Prohibition and modern genotypes did not statistically differ in their mean levels of maltotriose (P = 0.514). Glucose equivalents from fermentable sugars (i.e., total glucose from glucose plus hydrolysis of maltose and maltotriose) followed almost an identical pattern as that for maltose. Levels of maltotetraose through maltoheptaose were variable in both pre-Prohibition and modern genotypes throughout mashing. However, these maltodextrins usually decreased rapidly in modern cultivars while they increased or decreased more slowly in pre-Prohibition genotypes. In general, maltotetraose through maltoheptaose were higher (P < 0.0001) in Hanna and Hannchen (pre-Prohibition) worts than in other worts. Sucrose levels were relatively constant during mashing of most pre-Prohibition and modern genotypes. Fructose levels increased throughout mashing for all genotypes. Mean wort fructose levels of modern barley genotypes were significantly higher than those for pre-Prohibition genotypes during most of mashing.

KEYWORDS:

• Barley genotypes
• fermentable sugars
• glucose
• maltose
• mashing
• wort sugars

Acknowledgments

We thank Joseph T. Dietrich, Charles B. Karpelenia, and Andrew J. Standish for their expert technical assistance. We thank Dr. Gongshe Hu and staff for the production of the seed used to generate the malts for this study and Christopher H. Martens and staff for generating the malts.

Disclosure

Mention of a proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other suitable products.

Funding

Financial support was provided by the U.S. Department of Agriculture's Agricultural Research Service and the American Malting Barley Association, Inc.