Graduate Thesis Or Dissertation
 

Examining Environmental and Genetic Influences on the Brewing Performance of Hops (Humulus lupulus) and Barley (Horduem vulgare)

Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/t148fq25v

Descriptions

Attribute NameValues
Creator
Abstract
  • In short, the brewing process uses hot water to extract fermentable sugars from malt to make a wort that is bittered by hops and finally fermented by yeast to produce beer. The four key ingredients in brewing are malt, water, hops, and yeast. Malt is perhaps the key ingredient, as it contains starches and protein as well as the enzymes required to break them down and is the source of fermentable extract that is ultimately converted to beer during an alcoholic fermentation. Hops, the cones of the female Humulus lupulus plant, are used for both bittering beer and providing aromatic qualities. Hops are grown in various regions globally and differences in soil, weather, climate, disease pressure, and grower practices provide inherent variation among them. This variation in hop growing conditions leads to differences in final hop quality, which growers have begun to focus on in recent years. This relationship, called terroir or regional identity, examines how the quality of agricultural products relate to their place of origin. It encompasses the soil, weather and climate, topography of the growing location, and to a certain degree the influences of grower management in response to these influences. Specified growing regions have been established for other agricultural products, such as wine grapes, coffee, cocoa, and tea. Anecdotal knowledge and published research show early evidence of regional identity affecting hops. Several studies have shown differences in hop chemistry and sensory qualities among samples grown in different locations. However, more work is needed to understand the extent of regional variation and to determine which factors drives differences among hops grown in different locations. To assess the potential effect of regional identity on hops, three varieties were harvested from a total of eleven commercial fields managed by a single hop grower within the Oregon Willamette Valley. Weather, climate, management practices, and soil data were collected for each site. Multiple Factor Analysis of these data sets showed evidence of a location effect. As expected, chemical analysis showed sample groupings by variety but variation within each variety demonstrated the effect of growing location. Sensory evaluation showed significant differences between samples within the same variety. Variation within field and between fields of the same variety provide early evidence of regional influences on hop qualities. Seeds from the barley plant, Hordeum vulgare, are unsuitable for brewing until they are transformed via controlled germination and kilning during the malting process. While malting is a significant driver of malt flavor, recent work shows that other factors, such as genetics, may also influence flavor. To evaluate the contributions of barley genotype to beer flavor, two independent sets of barley germplasm were evaluated. Pedigree, quality of malt and beer, and beer metabolomic profiles were compared within and between the two sets. Sensory attributes of malt hot steeps and lager beers were evaluated, and distinct but subtle differences were reported. Distinct metabolomic profiles, attributable to barley genotype, were detected. In conclusion, metabolite variation observed is a direct result of genetic differences that lead to differential chemical responses within the malting and brewing processes, thus affecting flavor.
License
Resource Type
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Subject
Rights Statement
Publisher
Peer Reviewed
Language
Embargo reason
  • Pending Publication
Embargo date range
  • 2020-12-28 to 2021-07-29

Relationships

Parents:

This work has no parents.

In Collection:

Items

Thumbnail Title Date Uploaded Visibility Actions
file details VanSimaeysKarliR2021.pdf 2020-12-28 Public Download