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A Research Guide for Agricultural & Food Systems 401

Project Summary & Goals

Project Summary: Yakima Chief Hops (YCH) is still in the early stages of research and has assessed the volume of hop and animal waste available in the Yakima Valley. This project would require students to perform an in-depth literature review and provide industry examples and best practices for creating bioCO2 and RNG from hop waste and cow manure.

Project Goals will include 2-3 the following (to be scoped by the project team)

  1. Outline best practices to economically collect, transport, store, pre-treat and digest hop waste and manure. Include considerations for collection and storage of the waste at the hop farms and dairies.
  2. Compare the impact on digestion from different ag waste feedstocks.
  3. Determine best practices to collect and clean CO2 from the digestion process to convert into beverage-grade bioCO2.
  4. Perform cost analysis and emissions analysis to determine alignment with company CSR initiatives
  5. Determine the impact of Washington State’s Climate Commitment Act on YCH.
    1. Will creating/purchasing bioCO­2 help YCH achieve greater carbon emission reductions?
    2. Outline compliance requirements

A Note About Finding Resources

This project is going to require find information regarding various subjects (such as carbon dioxide (CO2) hop extract, supply distributions, digestion processes, carbon emission information, etc.) and to synthesize it within a literature review.

Listed below are resources that might assist you with this project. This list is by no means meant to be an exhaustive. Rather it is meant to get you thinking about what sort of resources you might need and where they may come from.

If you have any question, please email me.

Creating Search Statements (To find Answers to Questions Raised by this Project)

This project requires that you synthesize information from various resources.

Below are some keywords and search statements that may help you answer the questions raised in the project description.

To learn more about developing keywords and search strings check out this link.

Note: he following keywords and search strings are just some quick ideas, you may come up with better keywords and search strings yourselves.

Potential Keywords:

hop OR hops
"hop waste"
"hop pellet*"
carbon dioxide OR CO2 OR bioCO2
beverage grade
anaerobic digest*
digestion AND "waste feedstock*"
best practice* OR method* OR procedure*
collect* OR transport* OR stor* OR *treat* OR impact*
animal waste OR manure
"cost analysis*" OR "emission* analysis*" OR "carbon emission*"
Washington State* Climate Commitment Act

In practice, you'll want to try different combinations of keywords in your searches (which may include Title, Any Field, Subject, etc. searches. 

Here are a couple of searches to get you started:

best practice* OR procedure* OR method*
hop OR hops

Here is that search in the WSU Libraries' catalog
Here is that search in Web of Science


anaerobic digest*
hop OR hops

Here is that search in the WSU Libraries' catalog
Here is that search in Web of Science


carbon dioxide OR CO2 OR bioCO2
hop OR hops

Here is that search in the WSU Libraries' catalog
Here is that search in Web of Science


Note: Try different keyword combinations yourself. Also, try changing the search parameters (for example, try a "Any Field" search in place of a "Title" search and vice versa).


Find Background Information (and Summaries)

Information about Yakima Chief Hops

Washington State’s Climate Commitment Act (Overview)

The Brewers Association (Non-Profit Organization) - Solid Waste Reduction Manual

USDA Food Loss and Waste (Resources) 


Some Background Articles on Hop Waste:
Kopeć, M.H., et al. (2022). Biological activity of composts obtained from hop waste generated during the brewing. Biomass Conversion and Biorefinery, 12(4), 1271–1279. See article here

Siqueiros, L., et al. (2019). Energy Recovery from Brewery Waste: experimental and modelling perspectives. Energy Procedia, 161, 24–31. See article here

Find Scholarly Resources

Much of this project is going to involve finding scholarly research regarding a myriad of topics. Below are some of the best scholarly databases to get you started

Find Industry Info, Corporate Data, Popular Press, and Trade Publications

Helpful Industry Resources, newspapers, and trade publications.

  • Nexis Uni - Provides information on U.S. and international private and public companies. Info includes company/non-profits organization descriptions, size, locations, history, and more. You can also search across newspapers and trade publications. 
  • Business Source Complete - Allows you to search company and industry information across popular press, trade journals, product reviews, and much more. Also provides information regarding company and industry profiles. This may be helpful when for searching for information regarding other non-profit organizations.
  • Newspaper Source - This database provides selected full text coverage for 245 newspapers, newswires and other sources. 

For more in-depth information regarding corporate research, take a look at the Company Research Library Guide. 

See also WSU News and Newspaper Research Guide

Find Datasets

A datasset is the raw data that has been collected by researchers and government institutions. There are countless different types of datasets from countless organizations. Helpful datasets pertaining to these projects may include demographic information, opinion and market surveys, soil and horticulture maps, and so much more. 

  • USDA: National Agricultural Statistics Service (NASS) - NASS conducts hundreds of surveys every year and prepares reports covering virtually every aspect of U.S. agriculture. Production and supplies of food and fiber, prices paid and received by farmers, farm labor and wages, farm finances, chemical use, and changes in the demographics of U.S. producers are only a few examples. Also see the USDA Open Data Catalog

Literature Review Resources

About Literature Reviews

WSU Libraries - How to Conduct a Literature Review (Overview and Resources)


Resources for Keeping Organized

There are several free citation management software applications. These applications will help you organize, share, import, and export citations. These applications also work with Microsoft Word to allow you to easily cite sources and create reference sections within Word.

The most popular of these applications are Zotero, Mendeley, and EndNote.

You can learn more about those applications on this WSU guide. Such applications although helpful, do operate on a garbage in/garbage out principal.

To download these applications, or plugins, follow these links:

The WSU Libraries do not endorse any particular citation management application. That said, from experience, I've found there to be a little less of a learning curve with Zotero and Mendeley as opposed to EndNote.

Although I use all three applications, I tend to use Zotero the most.

Here's the quick start guide link which will get you going with Zotero.

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