Have you ever sipped a home brew that just didn’t taste quite right? Or maybe you’ve bottled your own beer in your bedroom, only to have it explode?
As many beer appreciators know, it’s easy to make really bad beer. But what if science can help?
In a busy Brunswick warehouse, surrounded by glass fermenters that float with yeast, La Trobe Bachelor of Biological Sciences student Ruth Barry is testing the theory – with exceptional results.
A brew built from over-the-counter probiotics
Ruth has been home brewing seriously for about five years. In 2017, she got a taste of success when she beat commercial brewers in a competition at Melbourne’s Good Beer Week.
“I decided to make a spiced sour beer, using a strain of Lactobacillus plantarum that you can buy from Chemist Warehouse! I was inspired by techniques used to make quick soured beers and New England IPAs,” Ruth says.
“The resulting beer smelt like fruit salad, with tangerine, mango, pineapple and citrus, and a clean acidity on the palate. And it was very, very drinkable! All six beers were judged by a panel, plus there was a people’s choice award, too. And my beer won both.”
No more boring beers – wild yeasts and bacteria at work
The search for unique beer flavours has inspired Ruth to push the boundaries of brewing. Instead of brewing with a single yeast strain, Ruth uses wild yeast and bacteria to add complexity to the taste.
“I’m interested in using non-traditional micro-organisms, which are often considered spoilage, to see what unique flavour profiles they can create.”
As independent brewing in Australia booms (the industry grew more than tenfold from 2006–2016), Ruth believes it’s more important than ever for brewers who work with wild bacteria and yeasts to understand the science behind them.
Choosing the wrong bacteria or non-traditional yeast varieties is unlikely to make a remarkable beer. Some breweries seem to think that sour beer needs to be aggressively sour, or that yoghurty flavours are acceptable,” she says.
“Typically, these breweries have tried using an unreliable source of probiotics to add aggressive strains of lactic acid bacteria, along with enteric bacteria and Bacillus – none of which offer positive sensory attributes.”
Ruth believes this ‘brewing by the seat of your pants’ approach risks turning off future beer drinkers.
“The majority of casual beer drinkers haven’t tried beers using unusual microbes to ferment with. If the first beer they try is a terrible representation of the style, they may assume that they’ll hate every sour or ‘funky’ beer. They may never try those styles again. This is detrimental to breweries making high-quality beers, who are effectively being shut out from a potential market.”
Studying the science behind fermentation
To this end, Ruth has chosen subjects at La Trobe that have taught her skills that are essential to the science of brewing.
“I learned a lot of practical skills in second year microbiology, like isolating and identifying bacteria and methods in aseptic technique, sterilisation and removing unwanted microbes from media and surfaces,” she says.
“It also gave me a good understanding of food safety, which is important when you’re extracting unknown microflora from the environment, to test whether they’re desirable to use in beer.”
Ruth also credits studying biochemistry with helping her to understand gene expression. Knowing which yeasts produce pleasant, reliable flavours and fragrances (known as ‘esters’) during fermentation means brewers can benefit from genetic selection.
“If you know what genes produce desirable esters, you can undertake breeding programs to select for new yeasts with all the right genes,” she says.
Becoming a career-ready brewer
Since the Good Beer Week competition, Ruth has brewed her prize-winning beer for the Australian National Homebrewing Conference Pairing Dinner. And she’s recently landed a new job that she considers ‘close to ideal’ at this stage of her career.
“I’ve just started as an assistant brewer at Boatrocker Brewing Co., which has a barrel ageing program. A large amount of their beers are fermented with mixed cultures, using yeasts such as Brettanomyces, and lactic acid bacteria,” she says.
She believes combining practical work experience with studies in science has been key to giving her an edge in Australia’s competitive craft beer market.
“The flexible learning options at La Trobe have made it possible for me to study while gaining real-world brewing experience. I intend to study while working for as long as I can, in the hope that one day I can research non-domesticated brewing yeasts.”
For Ruth, the future looks frothy. We’ll toast to that.
Where could science take your humble homebrew? Find out with a course in Biological Sciences at La Trobe University.