What’s are Randolph Macon Biology students learning these days? We can’t speak for their whole curriculum but they’ve been spending some time with us learning fermentation science.
“Many studies on how students learn support the notion that students learn best by doing. As such, I centered my Microbiology course on a hands-on project involving sourcing local microbes from Agriberry Farm.” says Biology professor Dr. Grace Lim-Fong.
You may remember last fall when Professor Dr. Grace Fong, her student Matthew Houle, and Origin owners Chris and Phil Ray took wort out to Agriberry to collect some wild yeast.
Dr. Lim-Fong and her student spent the semester isolating and growing strains for future Origin experimental beers.
Houle isolated a wild Saccharomyces yeast from under a raspberry shrub that was used to brew a Wild Raspberry Ale released at Origin in mid-April. Saccharomyces is a strain usually active in the first phase of Belgian Lambic spontaneous fermentation, (the main fermentation phase).
The project was taken to another level this Spring, when Dr. Lim-Fong decided to bring her Microbiology students on board to work on isolating more strains from the wort samples. Along with using experimentation to isolate further strains, they participated in a wort share. Brewer Winston Percefull made a basic wort using pilsner malt for students to brew with. The students spent the day watching the mash-in and mash-out process (how wort is made) and got some basic brewing instruction from Harrison Baronian, COTU’s head brewer.
While it is unlikely that the students will go on to a career in brewing, the knowledge they gain from this project will help them towards gaining mastery of microbiological knowledge and skills.
“Brewing is a natural context for learning microbiology: beer is made by a microbe (yeast), which carry out fermentation (a metabolic process) in wort (the product of enzymatic action on starches in malt) that also contain hops (which has antibiotic properties),” explains Dr. Lim-Fong.
What is wort?
In short, wort is the liquid extracted from the mashing process. The brewing process begins when you take milled malt and add hot water. Steeping your milled grain is called mashing. The process converts starch into sugars that will become food for the yeast during fermentation. Once the mashing-in process is completed, you mash-out, meaning you drain the liquid (which is now wort) from the grain bed so that it can be boiled. The boiling process sanitizes the wort and is when the hops are added for flavor, bitterness and aroma.
Each student team was given 5 gallons of wort to make into beer using ingredients of their choosing. Some dry hopped their beer, some added lactobacillus to sour the beer, and others added fruit.
“There is so much basic microbiology in brewing, and skills my students learn in class can be applied to clinical and diagnostic microbiology. It is a huge privilege to partner with Origin and Agriberry, and the Rays’ enthusiasm for student research cannot be overstated. I am particularly excited that my students have an opportunity to brew their own beer. They developed their own brews which were attentive to their research findings (e.g. How well does their Agriberry yeast attenuate?) and to brewing conventions (e.g. What is the hop aroma of an Australian-style ale?). My students will also present their research at the Biology Symposium on R-MC’s Research Day.” - Dr. Lim-Fong
Come taste of the line-up of 8 student beers on Friday, May 12th. Sample pours and full pours will be available, and the students will be here to tell you all about their beers.
Read more about the project on Randolph Macon's website here.
This past fall we took wort out to Agriberry farm in-order to collect yeast which natural occur within the local terroir. The wort was placed in 5 different locations on the farm to try and collect as many strains as possible in portable coolships. These locations were under the following species of berries and peach trees:
- Himbo Top
- Black Magic
After a day of collecting wild yeast, the wort was transferred to Cornelius Kegs and taken to Randolph-Macon College. From there, Professor Dr. Grace Fong and her student Matthew Houle started working to isolate viable yeast and bacterial strains. Samples were drawn from the Cornelius kegs and plated on universal beer agar (UBA).
There were a large number of yeast and bacteria strains collected, but the three most interesting yeast cultures found were taken to VCU for sequencing to find the exact strain of each. Two of the cultures came from the peach keg, and one came from the Himbo Top raspberry keg. They also suspected a Dekkera yeast strain, a common yeast found in Belgian lambics.
Here's a rundown of what Dr. Fong found after several weeks:
- Peach showed two genera of yeast, Hanseniaspora and Pichia.
- Himbo Top showed three genera of yeast, with Saccharomyces being the most abundant at week two.
- The specific gravity of all of the kegs decreased over two months.
- All experimental kegs contained Lactobacillus and showed a drop in pH from week 1 to month 2.
Interesting yeast found:
- Pichia (Bokulich and Bamforth, 2013). This yeast has low sugar fermentation and tropical fruit/ pineapple aroma.
- Hanseniaspora (Spitaels et al., 2014) is found in the first phase of Belgian Lambic fermentation and has low sugar fermentation.
- Saccharomyces (Spitaels et al., 2014). Found in the Second phase of Belgian Lambic spontaneous fermentation, the main fermentation phase.
After the yeast had been growing for some time, the brew crew sampled each batch of wort to identify which flavors and aromas they like for three new beers.
The work is not done! Dr. Fong will continue to research so stay tuned for more updates.