The lively yeast not only helps to develop the alcohol and carbonation for the beer, but its unique genetic makeup also affects the finished product's character by accentuating the floral, citrus and piney hops, and leaving a clean brew.
That delicate dance and its result easily could get muddled if another strain -- say, Belgian Wit Yeast -- is present in the tank. That yeast, used for Avery's White Rascal Belgian Wheat, could impart its phenolic and spicy attributes on the hoppy flagship beer.
Yeast cross-contamination is an issue faced by small- and medium-sized brewers that might not have the resources to dedicate tanks and brewing systems to a single beer. Like Avery, some of these smaller craft brewers utilize several different yeast strains to develop a wide variety of offerings.
"You want your customers to expect the same thing every time they buy it," said
The current tests that Driscoll and the Avery quality control team use to detect for cross-contamination take about 48 hours. If a yeast cross-contamination is detected, that batch of beer is immediately discarded -- a move that could cost Avery "tens of thousands" of dollars for dumping beer from a 240-barrel tank, Driscoll said.
To develop a quicker and more comprehensive solution to the problem, Avery Brewing turned to the
Since last year, the biotechnology-focused center has delved into the genetic profiles of Avery's yeast strains in an effort to develop a test that can determine cross-contamination in a couple hours, as opposed to a couple days.
Officials say the partnership not only could result in saved time, money and beer, but also lead to other advancements in science both in and outside the brewing industry.
Driscoll, who has a background in microbiology and molecular biology, joined Avery in 2011 after being laid off from a
Looking for a change in pace, he passed along his resume to Avery and quickly landed a role as a microbiologist for the brewery.
"I never thought that this sort of job existed when I was in college," he said. "... I think it's great to make some advances in beer science."
A few months in, Driscoll saw a way to do just that.
Avery's brewers preach sanitation and go above and beyond what's required -- considering the brewing operation off east
Avery's current process for checking for cross-contamination involves taking samples of the beer from the fermentation tank, streaking those sterile samples on media and popping the plates into an incubator. Forty-eight hours later, Driscoll and crew visually inspect the plates to see if an undesirable yeast is present.
"It's probably one of the first things I saw a solution to because of my background," he said. "I said, 'Oh, we can figure out the answer.'"
Through a mutual acquaintance, Driscoll was put in touch with
Headquartered in the basement of the university's
When provided with Avery's six most popular yeast strains, Huntley used an Illumina HiSeq 2000 machine to sequence many millions of small fragments of the genome. The small pieces overlapped, and then bioinformatics and computers were used to reassemble the pieces into longer sections, which allowed for the determination of the genetic fingerprint of each strain, Huntley said.
The differences between those strains are then used to develop chemical tests to ascertain the amount of strain cross-contamination, he said.
The CU research team has developed a working model for an assay and is close to testing that assay in a brewery setting, Huntley said.
The process -- which does not include any genetic modification -- is taken a step further by a BioFrontiers laboratory headed by
"(The Avery research) was sort of a nice, natural fit with what my lab does already," Dowell said. " ... The joke in the lab is that we're trying to make better beer and also understand why some people tend to get heavily addicted (to alcohol) and some do not."
The work at the
"They've never been able to ascertain this quick enough to be able to ask these questions before," she said.
"These yeasts are very different from your typical lab strain," he said.
Richmond said he is intrigued by how the yeast strains behave and sustain in highly volatile environments.
Additionally, because the strains are polyploid and aneuploid -- they have a higher number of chromosomes or have individual chromosome numbers that differ from the base copy number, respectively -- the research into their genetic makeup and performance could have other applications in the areas of Down Syndrome or cancer, Richmond said.
"It's cool to tie that back to really specific examples in the DNA," he said.
CU has completed the sequencing for the six Avery strains and is now in a process of developing a quick diagnostic test to identify the strains' presence in a batch of beer.
With the sequencing road map complete, Avery would eventually be able to conduct the diagnostic test in-house, Driscoll said.
"That can be done here," he said. "We don't have the equipment yet."
Driscoll said Avery's testing abilities can be upgraded immediately with a small PCR thermocycler, a device used to amplify DNA. Within the next year, Avery hopes to add a
The addition of new equipment will come as Avery builds a new brewery in Gunbarrel, increasing the size of its lab by six times.
"This is a first step," Driscoll said of the cross-contamination advancements. "We can do a lot more."
Technological advances in genomic sequencing have dramatically reduced costs and time, making the work more approachable for commercial applications, said BioFrontiers' Huntley. The HiSeq 2000, for example, can sequence a human genome in 10 days for under
"And we're at the Apple IIe stage," Huntley said, referencing the dramatic advancement of the personal computer. "Imagine what it'll look like in 10 years."
When the costs decline, it becomes more financially reasonable for labs such as
Lower barriers to entry also make it easier for the federal- and state-funded institute to meet one of its expressed goals: to serve as a resource for the business community, including burgeoning areas such as the craft brewing industry.
For Avery and CU, it's a gentlemen's agreement that could go on for several years.
Avery plies CU with beer samples, BioFrontiers utilizes equipment provided by genetic sequencing firm
Richmond plans to give a presentation about the research to the Rocky Mountain Microbrewery Symposium on
Richmond said he expects to publish the research this spring or summer.
Such an "open-source" approach could be beneficial for the craft brewing industry, Driscoll said.
"The better beer that all brewers make, the more it helps craft (beer) grow," he said. "The brewers that dedicate themselves to (creating) quality products are the ones that are going to succeed."
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