Talking Yeast

  Left to right: Christina (brewer at Folly), Siobhan (lead brewer at Burdock), and Anita (microbial enthusiast)
Left to right: Christina (brewer at Folly), Siobhan (lead brewer at Burdock), and Anita (microbial enthusiast)

This is a modified version of the talk I gave at the Queen of Craft‘s Yeast the Beast session in Guelph. Queen of Craft holds four sessions throughout the month of March, bringing in women involved in the beer industry to speak on various topics. Proceeds from each of the sessions are donated to Guelph-Wellington Women-In-Crisis. My session was as entertaining as it was educational. Anita Caven (Microbial Enthusiast) and Siobhan McPherson (Burdock Brewery) shared the stage with me and gave awesome talks. Thanks to Karyn and Wellington Brewery for hosting us and organizing this amazing event. 

Several people asked for the digital version of this talk. I hope you like my Pluto joke as much as I do. 



Talking Farmhouse Yeast

Two years ago, when we started to design what Folly Brewing was going to be, we decided we wanted to primarily work with farmhouse yeasts. There were a number of reasons for that: Not many breweries in Ontario were creating saisons and farmhouse ales year round; These yeast strains can allow for a large range of flavours; And (my personal reason) they allow us to brew my favourite types of beers.

Hello Saison

To talk about farmhouse and saison yeast, we should first address the question I am always asked: “So, what is a saison?” This is usually where I “hmmm” and “ummmm.” Saisons can be tricky to explain. Phil Markowski, brewer and author of the fantastic Farmhouse Ales: Culture and Craftsmanship in the Belgian Tradition puts it well:

“Modern saisons defy easy categorization. They can be as contradictory as they are uniform.”…” For many modern brewers “Saison” is a nearly blank canvas; its definition, a moveable feast.”

Saisons are hard to define. Typically, saisons are easy drinking with a peppery, fruity finish. Not a whole lot to work with here. At Folly, we consider a saison to be a beer brewed only with saison yeast strains. Beers brewed with both saison yeast and brettanomyces, we call farmhouse. But that’s just Folly’s interpretation – and we sometimes break our own rules, calling what should be considered farmhouse an “Old World Saison.” Currently, many breweries are making saisons using different Belgian yeast strains and adding spices to create peppery aromatics. Some are calling their saisons, “Farmhouse Ales.” It’s a little confusing.

Saison and Farmhouse Brewery History

At the very least, the history is a little more consistent. Phil Markowski calling saisons’ a “blank canvas” may refer to when saisons and farmhouse ales were first brewed at independent farms, scattered throughout what is now the Wallonia region in Belgium and Northern France. Farms that brewed had what were called “farmhouses.” Their ales were brewed during the winter, ensuring a lasting supply to be consumed by seasonal workers during the warm and busy summer months. As brewing occurred at various farms, there were no set styles or rules. Brewers would include whatever grains or ingredients they had at their disposal. Oats? Spelt? Wheat? It all worked, and it was all good.

When the lines between Belgium and France were divided, higher alcohol and malt driven versions of farmhouse ales, known as bière de garde, were favoured in Northern France. Known as a “beer for keeping,” bière de garde’s high alcohol helped preserve the beer’s drinkability while stored for long months before being served in the summer. As malt-forward and high alcohol bière de garde charmed French brewers and drinkers, Belgian farmhouse brewers adopted saisons. With lower alcohol levels, saisons could refresh workers without worry of intoxication. Saisons were also hopped more heavily than bière de gardes to avoid spoilage during winter storage.

Defining Modern Saisons

So, with this beer style having a hard time finding what defines it – how did we come to have yeast strains that, at the very least, have become common enough that we can say “that’s a Saison! I think?”

Our historical saisons, the ones created by farmhouse breweries in Belgium, depended on mixed fermentation. After the boiling process, wort would be cooled in a shallow vessel, then fermentation would take place in wooden casks. All of this would be happening on a farm, which would have been the perfect place for wild yeasts to hang out. Yeasts used in fermentation of these beers would be reused in the next batch of beer. Every farmhouse that was producing beer would have had its own unique yeast strain, which could alter the flavour of the beer. Even if a farmhouse brewer required the use of a neighbouring brewery’s yeast, that new yeast would soon pick up qualities from the farm it was currently being used at.

When this “Farmhouse Brewery” tradition in Belgium and Northern France ended after World War 2, commercial producers that had the equipment and resources to brew consistent saisons recipes survived. Unlike the smaller farmhouse breweries, these larger commercial producers could meet the demands of the thirsty public. Brasserie Dupont in Belgium was, and remains, the brewer of iconic saisons. White pepper and bright fruit, the yeast blend used to brew Saison Dupont has become the benchmark for when we say “This is Saison.”

Follies of Dupont

At Folly, our Praxis (a New World Saison) is brewed using a Brasserie Dupont strain. Light pepper and citrus fruits, Praxis is our New World interpretation of a classic saison. As homebrewers, we were very familiar with using Dupont yeast and how it should taste. When we made the step into professional brewing, that meant working with commercial pitches. That first Dupont yeast pitch, though we were confident in our abilities to brew, had us in a panic. My co-brewer and I sat in the back room of the brewpub nearly crying – we had ruined our first beer! What should have tasted like white pepper and fruit was tasting like burnt plastic. Trying to remain somewhat calm, and with shaking hands, we tested our gravity. After what should have been a normal fermentation time, this beer with its brand new yeast pitch, was taking a little longer than normal. Being new to the farmhouse brewing game – this was an important lesson. First pitches can stall a little. Be patient. Good things will come. We’re now on our 20th generation of this yeast, and like the Farmhouse breweries of old, this yeast has picked up some Folly house character along the way.

Belgian and French Saison Yeast

Along with similar yeast strains, this Dupont yeast strain belongs to the category of “Belgian Saison.” There is a second saison yeast category used by brewers known as “French Saison.” Believed to be from the northern France Brasserie Thiriez, French Saison yeast will have white pepper aromatics, but with a healthy dose of orange peel.

Modern Farmhouse

The term “Farmhouse” seems to have stuck around as historical saisons tended to have some wild yeast in there. With multiple yeast strains working together, they were naturally mixed fermentations. As the saison style made its way over to North America, modern brewers began to play with mixed fermentation through adding brettanomyces directly to their saisons.  


I’ve used the word Brettanomyces a lot already tonight. You probably noticed the word Brettanomyces, or Brett, at bars and on bottle labels. The reason it’s listed on tap boards and bottle labels is because it’s still very special. It has a mixed past of striking fear into hearts of brewers.

Ale and lager yeast belong to the genus saccharomyces. Brett is related, but different. Typically saccharomyces strains are called “clean” yeasts. The fact that Brett is not grouped with the clean yeast family should give you a good indication of where this is going! Working with Brett can lead to tricky equipment infections. A brewer may have wanted her saison to have funky brett character in it, but she didn’t want to find that same funk character in her pilsner. Brewers tend to be control freaks – the risk of your beer not working out due to a brett infection is scary. This ability to infect equipment and make beers that were meant to be clean “funky” keep many home and professional brewers away from the genus entirely.

Bad Brett

And when brett’s bad, it’s really, really bad. Picking up a glass of beer, bringing it up to your nose … and inhaling band-aids, fecal aromatics, and horse sweat does not sound delicious. Brett got itself a real bad reputation.

Brett loves to hang out in wood. Back in the old days of brewing, the oak barrels that were used to ship and age beers in England were particularly prone to developing an infection from Brett. When the Carlsberg Brewery was first isolating different yeast strains in the early nineteen-hundreds, they identified Brett as a cause of spoilage in British ales. They named it after the Greek for the “British fungus.”

Good Brett

And even though Brett could do great things for a beer’s flavour, it’s bad reputation kept it out of breweries for a long time. However, more and more, especially in smaller breweries, Brett is intentionally being used. While the risk of creating infection and spoiling beer is still very real, the benefits Brett can offer are too tempting for some. Brewers are experimenting with using different strains to develop complex flavours and to more carefully acid balance their beers. American IPAs can have their hoppy tropical fruit characters enhanced with Brett. Darker beers, like stouts and porters, can develop cherry pie flavours through Brett. And some brewers try to build funky and complex flavours through aging brett in there beer.

Beautiful Brett

While sometimes it’s assumed Brett beers are sours, this is not correct. Brett can acidify beer through lowering the pH slightly more than most other yeasts. This won’t sour a beer, but can certainly make it more tart. Various brett types will also create unique flavours which can make beer more complex and exciting.

Some common Brett Stains you might see include:

Brett Bruxellensis (or, as the cool kids say “Brett Brux”): If someone ever told you the pinot noir you are drinking tastes like “horse blanket” and “barnyard” – and you liked those flavours, then Brett Brux is for you. Used to bottle condition Orval, Brett Brux creates that classic earthy funk character found in so many brett beers.

Brett Claussenii (Brett C, My favourite of the brett strains): This strain of Brett can create tropical fruits flavours, like pineapple, and stone fruit. When blended with bright and fruity hops, this brett strain makes for delicious brews. Last Saturday, over 20 women joined me at Folly for International Women’s Collaborative Brew Day to brew a beer that was fermented entirely with Brett C. The brett will accentuate the fruity hops we used to make a super juicey, funk free beer.  

Brett Lambicus (Brett L – we’re noticing a trend here, right?): I love this strain. It can present like a cherry pie filling and can do some beautiful things to darker beers.

Saccharomyces “Bruxellensis” Trois: This strain is no longer considered a Brett strain, but it acts just like one. Like Brett, it can drop the pH and produce some cool, bright flavours in beer. At Folly we use a percentage of this strain in our Farmhouse beers to gain more tasty tropical fruit flavours. While this strain is the Pluto of our Brett solar system, we still love it just as much.

Farmhouse and Mixed Fermentation

So we know what saisons are. Or, at least we have an idea. They are peppery, bright, and dry and usually easy drinking. And we know what Brett does to a beer. It can create unique flavours, lower the pH resulting in a tarter beer, and if allowed to age they can create funky flavours. So, what is a farmhouse ale?

As I mentioned earlier, saisons were historically brewed in the farmhouses scattered throughout Wallonia and Northern France for the thirsty seasonal workers. When these saisons were being brewed, they were exposed to the wild yeast elements which could result in brett and other bacteria assisting in the fermentation – they were a mixed fermentation! At Folly, wanting to brew in the Farmhouse tradition, we blend our saison yeasts and brett strains to create “Mixed Fermentation” – Or, as we call them, “Farmhouse Ales.” This results in a dry, peppery beer with complex fruit flavours. Now, if you’ve ever been to Folly, you may notice that our Little Italy location in downtown Toronto is lacking the cows and fields typically required on farms. Thankfully we are able to rely on our brett strains to make up for our missing animals. The only pigs you’ll see at my brewery are already slow braised and covered in crackling.  

Mixed Fermentation: Two Approaches

In mixed fermentation brewing there are usually two approaches, and they can have fairly different impacts on the overall flavour of a beer. As I mentioned earlier, when Brett and saccharomyces are pitched together, there will be some funk flavours, but the end result is usually more fruity and bright.

On the other hand, some breweries will do an initial fermentation with a clean, saccharomyces yeast, then later pitch in Brett for a secondary fermentation. This approach tends to lead to what is commonly known as funk. This secondary fermentation allows the Brett to slowly ferment sugars the saccharomyces left behind, resulting in complex funk flavours.

For our “Farmhouse Ales” approach, we like to use saison yeast strains with Brett. The various Brett strains add tartness and fruity brightness to beer while the clean saison yeast produce dry and peppery aromatics that pair well together. But, that’s just our approach to Farmhouse. There are no hard and fast rules – just make sure it tastes good.

Catty Inkhorn

It takes some courage and time, but Brett can be somewhat dependable to work with. Well, until it all falls apart and your Brett goes rouge. Michael Jackson, the famous beer writer with an unfortunate (and amusing) name said on Brett’s behaviour:

“Saccharomyces is like a dog and Brett is like a cat. It’s a little less predictable. It’s going to do its own thing; it’s not going to come when you call it and sit when you say sit. If you can respect its individuality and suggest rather than dictate what it does in your fermentation, it can reward the brewer and the drinker.”

When designing one of our beers, we wanted to capture that cherry pie flavour found with Brett L for our Belgian Dubbel. The first couple of batches were perfect – malty, rich, and cherries. Then, something happened. Our Brett went a little crazy. If beer writer Michael Jackson was in the room, he would say our brett acted like a cat. It did it’s own thing. It started to pull our beer in a tart direction. Instead of forcing that Dubbel, we leaned in to where the Brett wanted to go. Since we listened to our Brett, we were rewarded with a lovely, tart Belgian style bruin that is now one of our core beers.

And there we are. A style that’s hard to define and sometimes still confuses new customers. A history that feels more like a romantic myth. A type of yeast that can wreak havoc in a brewhouse and make beer taste like sewage if mishandled, or completely alter the identity of your beer. With all these problems, why do both home and professional brewers keep coming back to saisons and farmhouse styles? Why are yeast companies, like Guelph’s own Escarpment Labs, creating new blends of brett? And why are there online communities like Milk the Funk, dedicated to sharing practical information on farmhouse and sour brewing? While hard to define, there are marks of identity in how saison yeast presents itself. Dry. Peppery. Bright. The history feels romantic, but even brewers are big softies when it comes to a good story. And while taming cat-like brett can be daunting, the rewards are so fruity and so worth it.