Identifying and Selecting Wild Yeast Strains in Hard Cider

View the project report

Commodities

• Fruits: apples
• Miscellaneous: other

Practices

• Crop Production: biological inoculants, food processing, food product quality/safety, plant breeding and genetics
• Education and Training: farmer to farmer, on-farm/ranch research, participatory research, technical assistance
• Production Systems: other

This project seeks to identify novel wild yeast strains, native to the regions of New England and New York state, to produce unique hard cider. Through a series of trials and tests we hope to select among native yeast species traits favorable for hard cider makers. Various geographic conditions and apple growing modalities will be used as backdrops for collecting wild yeast, ranging from orchards to wild apples. The pied de cuve method (PDC) will be used to collect native yeasts, which will be taken to the laboratory of our research partner and technical advisor, Swapna Subramanian at the University of Connecticut. Swapna will use experimental evolution on the pied de cuve community to select for advantageous traits that will improve hard cider quality. After evolution, we will be able to isolate wild yeast strains that have advantageous cider fermenting traits on base cider must (unfermented juice) and identify the yeast using DNA sequencing. The yeast will be tested on the must and studied prior to and following fermentation. Finally, top performing ciders will be blind taste tested among a panel of participants using the contingent valuation model and consumer willingness-to-pay (WTP) scale based on the research of Tozer, Galinato et al (2015). As a result of these findings we hope to publish in print and at cider conventions a “best practices” guide for wild fermentations to better enhance and expand the diversity of the American cider market. 

This project seeks to: 

• Establish a proper methodology for the collection, selection and propagation of wild yeast populations from both agricultural and non-agricultural environments using replicated experimental evolution and genotyping. 
• Discover a number of previously unknown wild yeast strains with unique and appealing sensory attributes and selected for resistance from common faults in cider. 
• Survey a statistically significant number of individuals in their satisfaction with 10 ciders inoculated from the 10 wild yeast strains described above.

Questions:

• What range of diversity among wild yeast populations can we expect from the various geographical locations and farming practices from which we will be collecting samples? 
• How much variability in perceived sensory attributes is available to cider makers through utilizing wild yeast in their ciders? 
• Using the tools of replicated experimental evolution, to what extent will we be able to select for advantageous traits, such as desired aromatics and flavors? Conversely, to what extent will we be able to deprive future generations of yeast of disadvantageous traits?
• What best practices in wild fermentation methods can be learned from the advanced tools in this study that can then be replicated by cider makers in the future without access to such tools?