The cultivation of wild yeast strains to add value to farmhouse fermentation

Progress report for FNC19-1199

Project Type: Farmer/Rancher
Funds awarded in 2019: $26,370.00
Projected End Date: 02/28/2022
Grant Recipient: Second Nature Honey
Region: North Central
State: Illinois
Project Coordinator:
Maggie Wachter
Second Nature Honey
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Project Information

Description of operation:

The operation consists of 25 bee hives located on five farms and one restaurant in Champaign Co. IL. All beekeeping is conducted according to biodynamic principles such as natural queen rearing, natural materials (wood, metal) and diverse farm environments that promote good nutrition. Any chemicals used conform to USDA organic guidelines.

Summary:

Yeast is fundamental to brewing. Most commercial yeast strains are produced in laboratories and have standardized flavor profiles.  Wild yeast, on the other hand, reflects the terroir of the local climate, crops and soil.   

Small farm breweries using wild yeast occupy a growing niche in the local foods movement.  However farmhouse breweries using wild yeast usually rely on open, accidental fermentation.   This project is intended to take the guesswork out of open fermentation.  

When honey bees gather nectar from flowering crops, they also gather yeast spores. Honey is therefore a natural medium for the collection of wild yeast strains.  We plan to take samples of honey from hives located on two mature farms.  Then, with the support of a microbiologist, we intend to demonstrate skills to control wild yeast selection under farmhouse conditions.  Home brewers and small-batch commercial brewers will help test and select the most promising strains. 

We feel that farmers and beekeepers are sitting on top of a commercial goldmine of wild yeast strains with diverse flavor profiles and attenuations.  This natural resource is currently under-exploited and uncontrolled.  Our goal is to increase the commercial viability of farmhouse fermentation by demonstrating how to control and replicate wild yeast.  

Project Objectives:
  1. Evaluate the potential of wild yeast as a crop by identifying and testing wild yeast strains in particular terroirs (fruit farm: Curtis Orchard and brewery farm: Big Thorn)
  2. Encourage farmers and beekeepers to exploit the wild yeast possibilities of their particular landscape (terroir) and products (beverage, baking, cheese, pickling, etc.) by sharing findings through social media, educational presentations, conferences and written information
  3. Identify scientific methods that would be useful for propagating wild yeast under farmhouse conditions
  4. Evaluate the impact of seasonal fluctuations and geographical constraints (such as monofloral environments) on the flavor profiles of wild yeast
  5. Encourage the development of innovative market bridges and income streams between local agriculture and local brewing

Cooperators

Click linked name(s) to expand/collapse or show everyone's info
  • Rachel Coverntry - Producer
  • Steve Halfar - Producer
  • Anna Schweig - Producer

Research

Materials and methods:

Our wild yeast propagation approach is one that the average farm would be capable of replicating at low, up-front investment and on their own property. It is especially useful to farms that have already established or are in the planning phases of establishing a microbrewery, cidery or meadery.

The best locations for harvesting diverse wild yeast strains are landscapes filled with wild flowers and fruiting trees. We originally selected two farms, Curtis Orchard and Big Thorn Farm, for our sources of wild yeast spores.  In 2021-22, we will include a third farm, Okaw Valley Apple Orchards. This farm is unique in its commitment to natural farming methods. We will partner with honey bees on all three farms, using samples of honey for collecting wild yeast strains. 

Following propagation of promising strains, we will screen them for viable sensory profiles in small (~1liter) batch fermentations using malt extract provided by a local brewery. 

Selected yeast isolates will then be propagated and supplied to local homebrewers.  Brewers will pitch the yeast in 5 gallon fermentations using a standard, neutral beer style (e.g. blond ale, traditional mead, cider) for comparative sensory and commercial evaluation.  It is hoped that local craft breweries might use the most promising yeast strain(s) brewing.

Yeast strains will be cryo-genically preserved indefinitely for future propagation. A booklet will be published for farmers, beekeepers and other interested brewers to summarize our research.

Research results and discussion:

In the first year of research, 2019-20, we analyzed seasonal honey (spring and fall) samples.  Although we found some interesting yeast strains, none of the samples were shown to contain brewable yeast strains.  This led us to speculate that perhaps the intensive farming methods of the Midwest might create an environment that reduced the survival opportunities for brewer's yeast.  We subsequently sought honey samples from beekeepers from other parts of the country such as Maine, Georgia and New Hampshire.  Unfortunately we were unable to isolate brewer's yeast in these samples.

To date (February 2021) the project's microbiologist, Dr. Terese Barta, has tested 17 different honey samples from the following states: Illinois (9), Wisconsin (4), Maine (2), Georgia (1), and New Hampshire (1). The following yeast species were identified by MALDI-TOF mass spectrometry by Dr. Jim Lawrence in the UWSP Chemistry Department:

Candida magnoliae (majority of isolates)

Candida parapsilopsis

Candida guilliermondii

Rhodotorula mucilaginosa

Zygosaccharomyces rouxii

Aureobasidium pullulans

There are also several isolates from honey and bees that have not yet been identified (apparently not in the MALDI-TOF library). At present, we are pursuing means of identifying these isolates by DNA sequencing.

In 2020-21, we also received 31 isolates from microbiologist Jason Ridlon. These isolates were also tested using MALDI-TOF mass spectrometry. Of the isolates that were received from Dr. Ridlon, the following species were identified: Candida magnoliae, Candida parapsilopsis, and a single Saccharomyces cerevisiae, a type of yeast that is commonly used for brewing  The majority of other isolates were identified as C. magnoliae.  

In addition to testing honey, in 2020-21 we also attempted to isolate yeast from bee intestines, and from wild flowers. Candida magnoliae was recovered from Georgia bees. Metchnikowia reukaufii, which may provide flavor enhancement in brewing, was isolated from Clintonia (corn flower) in Wisconsin.  Both the Saccharomyces cerevisiae and Metchnikowia reukaufii isolates will be propagated and tested for brewing suitability.

It took a long time and many attempts to isolate two promising strains of yeast.  In February 2021, we applied and received approval for an extension of one additional year of our grant.  We plan to use the extension to propagate our isolates and test them further. We are also looking forward to the participation of beekeepers from other parts of the country who might respond to our call for honey samples in two leading bee journals (March 2021).  We hope that honey samples from a wider geographic net might provide us with a better understanding of the relationship between bees, yeast and brewers.

Participation Summary
3 Farmers participating in research

Educational & Outreach Activities

5 Published press articles, newsletters
2 Webinars / talks / presentations

Participation Summary:

18 Farmers
3 Ag professionals participated
Education/outreach description:

The SARE project was announced in the local newspaper, the News-Gazette. (Spring 2019) 

A Facebook page called Yeast Garden was established to illustrate and inspire yeast experimentation. (Spring 2019)

In 2021-22 we plan to enlist beekeepers in other parts of the country to contribute samples of raw honey for testing.  We will do this through letters to the editor published in the March 2021 issues of American Bee Journal and Bee Culture. We are hoping that other areas of North America might unlock the power of honey bees to gather yeast strains suitable for brewing.

In 2020, the pandemic affected three planned educational and outreach events:

The project was announced to the local brew club, the BUZZ, in the fall of 2018 and again during the spring of 2019.  The club's president and some members expressed interest in participating in the brewing portion of the project.  One beekeeper/brewer club member who was starting a commercial meadery expressed particular interest in brew-testing the experimental yeast.  Unfortunately the club suspended meetings in March 2020. Until the club resumes meetings, we plan to work with individual home brewers to help us test promising strains.

In August 2020, we planned to present our project at the annual meeting of the Eastern Apiculture Association.  Unfortunately the conference was cancelled due to the pandemic. 

In 2020, our consulting microbiologist, Dr. Barta, applied for and received an auxiliary grant from the University of Wisconsin for equipment to test air and surface quality around the hives. Such analyses might have helped us understand better how environmental factors surrounding bee hives might affect the presence of brewer's yeast in honey. Unfortunately, for economic reasons related to the pandemic, the University has frozen faculty grants indefinitely. 

 

 

 

 

Learning Outcomes

5 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
Lessons Learned:

I learned that while it seems reasonable to isolate strains of brewer's yeast in honey, it requires persistence!

Project Outcomes

5 Farmers changed or adopted a practice
1 New working collaboration
Success stories:

While we have not yet isolated a yeast strain suitable for brewing, we have noticed that the hives located in isolated and forested areas, such as the Appalachian Mountains of Georgia or the wilderness of Southern Illinois contained better yeast diversity.  

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.