While in Brussels I had the opportunity to visit the last brewery in the city which still produced spontaneously fermented Lambics. The Cantillon Brewery is not in the heart of town. It doesn’t have a steel and glass façade with a commemorative walkway or a landscaped entrance. It is south of the old city, in a mixed commercial/industrial/residential neighborhood. The building is entirely unremarkable and the entrance is an almost unmarked garage door across from a large open area overgrown with tall grass. But once inside, I found an idyllic scene. The family that owns and operates the brewery was gathered around several open wooden crates filled with apricots. They were de-pitting the fruit which would later be blended with lambic to create their “Fou’foune”. I even got to taste an apricot right off the knife. The woman who offered it to me is the last living direct descendent of Paul Cantillon, the brewery's founder.
The self acclaimed “last traditional brewery in Brussels” started nearly 100 years ago and still brews over a 1000 hectolitres of beer in equipment from the 19th century (figures from brewery pamphlet). What makes Cantillon interesting for me, is that all of their beer is spontaneously fermented. This type of fermentation is a window into the past, as before the rise of modern carefully controlled brewing techniques, all beer was spontaneously fermented. Thus these brews may be the closest thing we can currently taste as to what the ancient Egyptians and Sumerians drank thousands of years ago (sans hops which are a more recent ingredient).
In a small loft above the top floor of the brewery, lies an enormous copper cooling tun where the beer is exposed to the unique microflaural ecosystem which has developed on the walls and in the spider webs of the Cantillon brewery for the last century. The beer is inoculated with wild yeasts which give it the complex sour flavors that lambic beers are famous for. After the tour I worked up the courage to ask a pressing question:
Me: “Because your product relies so much on the local bacterial and fungal ecosystem, I was wondering if you have noticed any change in the last half century or so as more and more international travelers make their way to Brussels, bringing with them their own bacterial and fungal ecosystems.”
Brewer: “Nope”, “wait, did you bring in bacteria with you!” (I’m pretty sure the second bit was a joke. Answering this question in the positive could be bad for business, so I assumed that the brewer was avoiding the subject. Looking back though, I wonder if he was being earnest with me? Perhaps the changes are too subtle, or maybe indigenous species have evolved to fit the geographical/biological niche so well that they crowd out any foreign competitors. Brewing only happens between October and April, when the climate is cold enough to cool the beer quickly and this might effect microbial competition as well. As I am just speculating, I will leave this an open question, and if a microbiologist or a brewer out there has any explanation please don’t hesitate to leave a comment!
Whether or not the beer at Cantillon has changed, it is still mind-bendingly fun to taste. A product of hundreds of different fermenting agents, the tart acidic flavors are so different from the tastes in commercial ales and lagers (these almost always have carefully controlled inoculations and fermentations by only a single species of brewers yeast).