Plant researchers help brew new ale

When university plant diagnostician Tom Evans was asked to help find a yeast sample that would be used by Dogfish Head Brewery to create a Delaware-themed beer, he was excited for the opportunity.

"It was a novel project for my laboratory and [we were] working with farmers that we had worked with in the past in our role as plant pathologists," Evans said.

Along with fellow plant scientist and diagnostician Nancy Gregory, Evans discovered the yeast culture Kloeckera, which was used to create the Delaware Native Ale.

The beer, created using ingredients found exclusively in the state of Delaware, helps promote local farmers and brewers who helped craft the ale.

Gregory, an extension associate of the plant and soil science department, said yeast reacts as a catalyst during the fermentation process, facilitating the conversion of sugar to alcohol and carbon dioxide.

Evans and Gregory began the search for the state yeast by placing Petri dishes in different environments around the university and trapping fruit flies, knowing they carry bacteria and other organisms as they travel. Gregory said approximately 100 plates were used to collect several different types of bacterial growths and different types of yeast.  

Gregory's role on the project was to isolate the most viable yeast samples for the process to determine which would work effectively in the beer making process.  

By smelling the contents of the dish they were able to tell which samples would make better-tasting beers, Evans said.

After reducing the 100 Petri dishes to 20 selections, they decided which samples to be sent to Dogfish Head. The samples were then narrowed down to five choices before the fermentation process began, Gregory said.

"[Then] they were narrowed down to three and carried through the sequencing process," Gregory said.

Dogfish Head took the selections and produced small batches of the beer and fermented them, Gregory said.

The ale, which combines peach and pear flavors, was tapped on Halloween and sold at the Dogfish Head restaurant in Rehoboth Beach. Evans said Dogfish Head officials are working to make the yeast publically available.

Jimmy Williams, an employee of Dogfish Head Brewery said that Dogfish Head does not typically set out to make a beer with a specific flavor. However, creators knew the ideal flavors would come from fresh peach and pears from Fifer Orchards, a local Delaware orchard, Williams said.

"It is a very drinkable, very quaffable beer," Williams said. 

Yeast grows around rotting fruits and Fifer Orchards collects the discarded crops, making it a logical place to obtain samples.

Compared to other beers produced by Dogfish Head, the ale has a slightly lower alcohol content. Most Dogfish Head beers are 9 percent alcohol, but Delaware Natural Ale is slightly lower, Williams said. 

Dogfish Head hopes to turn the ale into a seasonal beer, changing the flavors and fruits that are added with each season.  They will continue to use culture number eight, keeping ale a fully native Delaware beer.

"You can isolate yeast easily from the environment, its everywhere," Evans said. "The question is, ‘is it a good yeast, does it make a good wine or beer?'"