Time & Yeast: Brasserie Thiriez

On my first day at Brasserie Thiriez last week I spent a solid chunk of my time labelling by hand a batch of bottles whose labels would not cooperate with their labeling machine. The beer was called Train to Mars and about half of it was heading to the States via Shelton Bros and the other half going to a bottle shop in Paris the next day. After a few hours I started to read the label and its subtitle caught my eye…

“A Saison de Mars hopped with Mosaic, Aramis, Simcoe and fermented with the world famous Thiriez house yeast.”


Here is a photo of the label,

some tagline
some tagline…


As a brewer, I have used a *very* similar strain for dry, hoppy saisons in the past with some pleasant results. In fact, it was the yeast that led me to Thiriez in the first place by way of Jester King.

However, I don’t think I realised until then how prominent the strain was worldwide. If you wish to know more about its influence, All About Beer posted an article last month here.

So here I was at Thiriez, having the opportunity to ask every question about the strain and fermentation I could think of. You should see my notebook now, nearly every page with some scribbling of some temperature or trick. However, the two things that struck me most about Thiriez were the yeast itself and the fermentation times.


Daniel in front of the taproom and old brewery
Daniel in front of the taproom and old brewery

When I learned to homebrew I was told that my beer would ferment for 5-14 days after which I could prime it, bottle it and await a further 2-3 weeks for a secondary fermentation in the bottle for carbonation. I tend to think that most English speaking home brewers learned something similar. In the professional craft-beer industry, a fermentation time of 5-10 days would be normal if not even a little long. I can’t help but think that the sheer number of pro-brewers starting as home brewers has largely influenced this for all intents and purposes industry standard.

So when I got to Thiriez, saw 6 tanks and quickly did some math I assumed that Daniel would be  brewing at least 3 batches a week. Then I had a look around at the temps of these tanks and the documented information. Some of these beers were brewed 3 weeks beforehand and were not even crashed yet! [crashing referring to chilling to near-freezing temperatures to assist with flocculation and beer clarity] When I started talking to Daniel about this ‘inefficiency’, it completely changed the way I saw clean pure culture fermentation.


Daniel selected his strain from a lab in Brussels when he started his brewery. He knew the qualities he wanted and the lab grew up a few cultures for experimentation. The one they chose was a single strain, meaning it is not a proportional mix of a few different cultures; rather, a single cell slowly grown up into pitchable quantities. It’s a Saccharomyces cerevisiae strain, so it’s not what we might call ‘wild’ producing funky flavours.

The yeast has gained popularity for its versatility and the flavour compounds it produces. The All About Beer article covers this well. Daniel uses his yeast for almost all of the beers he makes. the blond, ambree, hoppy blonde, 2.9% table beer, white and most of the seasonals are all fermented with the strain. While there is an unmistakable house flavour, each beer has its own yeasty nuances none too overpowering which varying from banana-clove in the White to a spicy pepper in the table beer. It’s pretty amazing tasting these side by side and seeing what this strain can do. A yeast like US-05, the dry Safale American ale strain, has nothing on the Thiriez yeast’s subtlety and variation. However, the main factor in these flavours comes from differing fermentation schedules harnessing or releasing certain compounds at certain temperatures to create the trademark Thiriez balance.

Top of the brewhouse and 4 40hl FV's
Top of the brewhouse and 4x40hl FV’s


As I mentioned before I was initially shocked to see how long Daniel’s beers spent in the tank. The normal fermentation time at Thiriez is four weeks before packaging then another two weeks following for bottle conditioning, 2-3 times longer than your standard APA/IPA brewpub or brewery. Daniel’s reasoning for this comes largely from a respect and care for his yeast. After 18 years working with the same strain, he does not like to shock it with quick temperature changes which stall the yeast’s work. Additionally while the major bulk of fermentation has completed in less than 5 days, he allows the yeast more time at slowly decreasing temperatures to continue its conversion resulting not only in a drier beer but also encourages the gradual consumption of harsher compounds into more subtle balanced ones more often associated with longer fermentation temperatures.

Seeing the results of a fermentation such as this one made me reflect on mine and the larger industry’s current tendency towards 2 week fermentations. While I cannot trace the exact history, I believe it has to do mostly from our English language. The home brewing movement in the States and Australia grew largely in part to a little help from our friends the British. While the rest of the world had conglomerated into a few light-lager breweries the English were experiencing a revival of its traditional styles. Books were written, research was getting done and the English reestablished a dying culture with their ESB’s and porters.

With our adoption of their techniques was an acceptance of their yeast and yeast care. Typical English yeast is highly flocculant and a low attenuator. Its like a shift-worker, gets in, gets work done and gets out as soon as it can. It leaves a spectacularly clear beer but also unfermented sugars and undesirable compounds such as diacetyl. With this yeast a fermentation past 5-7 days is useless. The yeast falls out of of suspension and declares its job is done.

Belgian yeast in contrast, behaves somewhat more similar to wild yeasts with a slower fermentation. In general, wild yeast consumes easily available sugars at similar rates to normal brewing yeast. However, wild yeast also contains an innate fight or flight tendency. Once the easy sugars are consumed the yeast does not fall out ready to die; instead, it pushes on less rapidly converting more complex sugars in attempts of self preservation. At the same time, these wild yeasts convert some of the harsh undesirable compounds into more subtle and complex flavours. This is not an exact science requiring a brewer to know their yeast and about proper barrel ageing; but, it’s a large part of the art of ageing and blending for sours and barrel aged beers.

While Belgian strains are not wild yeast by any means, I came to understand that they fall somewhere in between the extremes of English yeast and wild strains. Their characteristics bear resemblance to parts of both sides. When this struck me, I realised that I had certainly not given enough time to many of my fermentations. I had been demanding the yeast to work on my production timeline instead of allowing it to do its work in its time. All we can do as brewers really is create a happy, healthy environment for the yeast in the wort because the rest is simply not up to us.

It is often said that brewers make wort, yeast makes beer. It’s about time I start to believe it.



What is Farmhouse beer?

Craft beer has issues with nomenclature. Even calling beer ‘craft’ causes problems.

While defining an industry may be the worst of our problems, it is far from alone. The growth rate of our craft, sorry, outpaces our ability to delineate its differences. For example, the development of new primary ingredients, ie. malt, hops and yeast, cultivates brewers to create never-before-seen unnamed styles.  Additionally, diversity in brewing styles yields brewing companies brandishing names such as artisanal, sour and gastrobrewery. While the vocabulary grows, so does the ambiguity.

In an effort to dispel a touch of vagueness, I hope to in what follows answer the question of what sets farmhouse brewing apart. I have a deep passion for the aforementioned tradition; indeed this is the reason for the blog itself. Furthermore, I believe the rebirth of these sorts of ‘back-to-the-roots’, holistic methods and ideologies embody the spirit of our industry.

A recent article by the Food Republic set out to answer this question as well. While I loved the explanation they quoted from Jeff Stuffings of Jester King in Austin, the articles appearance in the current craft beer landscape encouraged me to continue breaking down the differences between farmhouse-styled beers and Farmhouse beer.

To be short Farmhouse beer comes from Farmhouse Breweries. The capitalisation of the word ‘farmhouse’ marks its use not as an adjective, but rather a noun. Simply put, a Farmhouse brewery exists, it is a place and by making beer in the way they do, they produce Farmhouse beer. Contrast that to breweries reproducing the styles of Farmhouse brewing and adopting the word to describe their beer.


In other places as well as in the Food Republic article, the folks at Jester King have expressed Farmhouse beer as beer with a sense of place. I have loved this distinction since I first heard it, with a meaning deeper than it solicits.


One of the ideas about this description is the physical location of the brewery. While I would not claim that a Farmhouse brewery necessarily has to be set on some random farm, I do mean to say that the land the brewery is set on becomes special for the reason that it might now be the home of a Farmhouse brewery. A Farmhouse brewery can’t just uproot because it has grown out of space in its current leased building, a Farmhouse brewery has a connection with the land it is on.

Brasserie Cantillon comes to mind for describing this. While there could be some debate as to whether their ‘Lambics’ are Farmhouse beers, this is an argument of style. The brewery itself is located in the middle of Brussels. For many craft beer lovers, visiting the brewery turns into a sort of pilgrimage. In dealing with growth, they purchased a small building down the road to age more beer in without upgrading to a larger system or moving to a place that could handle more barrels. If they had moved their location, something would have been lost. Furthermore, they could not contract their beers to be brewed elsewhere, they just wouldn’t be Cantillon beers. For Cantillon and Farmhouse breweries alike, brewing here is not the same as brewing there.


What follows from this is a second difference evoked by having a sense of place, the adoption of location. Farmhouse breweries and Farmhouse beer are a product of their region. They use local ingredients, raw and unprocessed. They are not driven to reproduce a beer they had elsewhere or utilise rare ingredients from the other side of the globe, instead they aim to work with their local producers, flora, microflora and even fungi to develop balanced beer with a character of its home. Its an approach more found in cooking than in brewing.

The best example of use of a local ingredients would have to be the utilisation of local, wild yeast for fermentation. Yeast is the single most important flavour producer in beer. Harnessing and employing wild yeast can produce inconsistent results, its risky. It takes a whole lot of time, experience and open-mindedness to use local, wild yeast in commercial brewing. A Farmhouse brewery must be willing to discard batches that do not turn out to be drinkable. Being a Farmhouse brewery implies that this loss would not constitute a move away from a commitment to using local ingredients; instead, a moment to re-double their dedication to creating better beer from what they have. Jester King in Austin is very open about their use of wild yeast as well as its ability to take beer places they do not wish, resulting in dumped beer. While the chance of off-batches exists, the potential for delivering beautifully complex beers keeps Farmhouse brewers going.

The second most important local ingredient is water. Water is the largest ingredient component and its chemical composition has the ability to make beers hoppier, softer, more rounded or more crisp. Pretty much every commercial brewery would augment their brewing water to match or enhance the style that they are brewing. However in Farmhouse beer, brewers embrace the water that they have and brew styles suited to their land with minimal-to-no adjustment of their water profile.


A third distinction given by the phrase has to do with the people. When we think of a place like our home or an office, we are most impressed by the people that filled the place rather than the four walls and roof itself. Farmhouse brewers and craft brewers alike strive and succeed to make their breweries a space from the people to the people. They are passionate about what they do and could likely talk your ear off if you give them the chance. In Farmhouse brewing, some of the brewers live onsite or very close to their breweries making them an extension of their home. Visiting a Farmhouse brewery is an invitation into someone’s personal space.

The idea of people making a place is exemplified well by Brasserie Thiriez in Esquelbeq France. Founded and run by brewer Daniel Thiriez and his wife, the brewery is open every day they brew. In a remote location, they welcome visitors on your time not theirs, an open-door policy. But crafting exceptional ales is one part of their vocation, they also run a B&B on-site if you want to stay.

Finally, for a beer to have sense of place it needed to grow up at some place. By spending large portions of its life in stainless fermentors, oak barrels or foeders, Farmhouse beer develops its own character. It does sound crazy but if you listen to some of the best beer blenders in the world talk about their barrels, you come to understand that we are just bystanders to a semi-magical process. In Farmhouse brewing, the utility of wild yeast often warrants slower fermentation times then clean pure-pitch fermentations. Batch by batch, the yeast mutates over time becoming something possibly unrecognisable from where you might have started. In a sense, farmhouse brewing is a letting go of the production and an embracing of nature’s timeline. The beer tells you when it is done, not the other way around.

Time is a component of Farmhouse beer exemplified in almost any sour beer brewery. The Boon brewery, for example, in Lembeek Belgium produces exceptional sour beer that often spend three years in oak before packaging. The Rare Barrel in Berkeley California generally allows 6-24 months for their fermentations allowing the beer to develop on its own. Taking time is commonplace for sour breweries and Farmhouse breweries alike; however, it is a rarity in the market as a whole with the vast majority of beer sold around the world spending somewhere between 3-12 days from grain to bottle.

Putting it together

What you end up with when combining these factors, and others that I have not listed here, is a product that is more than the sum of its parts. You produce beer with a soul. A soul filled with the place it is from and the people who produce it. The French winemakers call it terroir, a term becoming more popular for Farmhouse brewers. Farmhouse beer is not a style, it’s a product of a place with the substance of that place.