The Microbiology of Beer
Beer is as much a science as it is an art. I actually wager it’s more science. That’s why it’s so important to understand what’s going on behind the scenes in the brewing and fermentation process.
Enter Alastair Gillespie – brewer, microbiologist, biochemist and all around scientific bad-ass.
I caught up with Al to ask him a couple of questions about his chosen field of study and how it has impacted his brewing skills.
Mitch: “Al – give us the rundown of your scientific brilliance. What’s your background? What did you study at school?”
Al: “I did an undergrad Bachelor of Science in Microbiology and Human Physiology at UCT from 2007-2009 inclusive. I then did my Honours in Molecular Cell Biology, which mostly consisted of Biochemistry and Genetics. My thesis was titled, “Characterisation of the antioxidant and antimicrobial properties of twenty one mushrooms species found in Cape Town.” It involved doing various extraction of wild and cultivated mushroom species and then testing the various fractions for antioxidant capabilities or activity against yeast, gram positive and gram negative bacteria.”
Al: “Haha! Not quite as complicated as it sounds.”
Mitch: “So how have you applied this to making beer? How does one go from mushrooms to IPAs? What has Devil’s Peak done to put those skills to best use?”
Al: “Having studied Microbiology and Biochemistry helps with making beer in that it has given me insight into how microbes, such as yeast, like to be treated. Avoiding stresses on the yeast is second nature to me as is aseptic technique. Fermentation is a big chemical reaction. You can control the inputs and the conditions the reaction takes place under. It is for this reason that Devil’s Peak have decided to invest in a microscope. The health of your yeast culture is of utmost importance! If you add dead or unhealthy yeast, you cannot expect to get a good fermentation or beer when all is said and done. Alongside many other tests, the microscope enables us to see how many yeast are present per ml and what percentage of those are alive and kicking. When you go through all the effort (and money) of making a big batch of beer, it would be careless to pitch dead yeast!”
Mitch: “Yeah! SCIENCE! Haha . . .no? Breaking Bad? No?”
Al: “Brewing, spear fishing and surfing leaves very little time for TV.”
Mitch: “Alright, alright . . . so we’ve got a picture of what happens under the microscope. Give us a rundown of what’s going on here.”
Al: “So I’ve diluted the yeast we collect at the bottom of the fermenter – 1 part yeast to 49 parts saline solution. Then I’ve mixed that 1:1 with methylene blue dye. It dyes dead cells while leaving live ones untouched. I can then work out the number of cells/ml and then the percentage viable cells. As you can see, this yeast is very healthy and ready to be pitched!”
Microbiology – one more reason #DPBC produces beer as it should be!