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Matthew Park of Burdock Brewery and Music Hall uses yeasts to influence taste of craft beer his craft beer. He is seen in his brewery on September 13, 2015.JENNIFER ROBERTS/The Globe and Mail

To talk with craft beer fans is to talk in a multitude of languages – borrowed words such as saison, gose and lambic have become commonplace over the past few years. And while hops have most recently dominated the conversation, with names such as citra, cascade and willamette becoming code for certain aromas and flavours, the discussion is rapidly shifting to yeasts.

Different strains of yeast have the power to harness and alter the flavour of a brew – think spice, clove, pineapple and even barnyard funk. As unorthodox flavours prove increasingly popular among craft beer aficionados, yeasts are fast becoming the newest lever for adjusting the flavour profile.

"If you tried an English pale ale with a [yeast] strain more typically used for a Belgian Trappist-style ale, the results would be very different," says Angus Ross, co-owner of Guelph-based Escarpment Labs, which specializes in yeasts.

While the vast majority of commercial beers are brewed with yeasts known as saccharomyces, or sach for short, Ross and his partners, Richard Preiss and Nate Ferguson, (all home brewers with backgrounds in microbiology) are most excited about a group of strains called brettanomyces. Brett, as they're called, could be their bread and butter.

"People refer to brett and sach like cats and dogs. Dogs are like saccharomyces, they do what they are told. Brettanomyces are like a cat: It does its own thing and changes its mood," says Matthew Park from Burdock Brewery and Music Hall.

Brett is moody and broody – it takes its time devouring residual sugars that most sach won't bother with, yielding flavours that can range from tropical fruit to barnyard.

Unorthodox yeasts, such as the wild-harvested yeasts that Escarpment has been collecting, can help bring about even more complex beers for brewers.

Park and his brewmaster/business partner Siobhan McPherson have been using strains of brett and sach from Escarpment to make their saison, a type of Belgian farmhouse ale.

The sach yielded what Park called, "a classic saison – a little spicy, clovey, fruity."

But when they bottled their endeavour for a month, the brett showed its true colours, or flavours. "It developed notes of pineapple and even a barnyard funk, but in a good way. It was incredible, and so shocking to see it change so much."

Working with a local yeast lab such as Escarpment means the opportunity to experiment with more flavours and, just as important, an ease of access to them.

"It costs almost as much for the yeast as the shipping from labs in places like California to Toronto," says Chris Conway, a brewer at Habits Gastropub on College Street in Toronto.

Conway runs the nanobrewery inside the pub, and the guys from Escarpment have been known to personally deliver their wares. Not only is Conway saving money, he's also working with them in developing beers.

"We collaborated with Escarpment not only on yeast but on recipes," he says. "This much rye malt, this much wheat malt, these hops we would like, and then they blended the yeasts for us. It was a back-and-forth process."

The result is a series of beers named after the yeast lab, with their second endeavour recently untapped to pub patrons.