Founded in the year 1900 by a traditional Belgian brewer, Paul Cantillon, and his wife, Marie Troch, Brasserie Cantillon was a blending house for the first 37 years, selling lambic beer and gueuze, with wort procured from other producers.

Unlike carefully selected strains of yeast used in commercial beers, lambics are left in open vats where native wild yeast and bacteria are allowed to “naturally” ferment the wort. Once fermentation begins, the beer is stored in barrels and left to age for up to 3 years. This gives lambics their signature “funky” and refreshing sourness.

Gueuze is a blend of young and older lambics and left in wine bottles for a second fermentation of residual sugars for a year. Since wild yeast and aged hops are added to lambics there is no hop flavour or aroma. Gueuze tastes dry, cider-like and sour.

The founding couple’s sons, Robert and Marcel, joined the business in 1937, and the first batch of its own beer was brewed in the following year. But the Second World War and its aftermath brought about a decline in sales, forcing Robert to sell his share to Marcel. It was Marcel’s daughter, Claude, who stepped in to save the family business.

Claude’s husband, Jean-Pierre Van Roy (himself a fourth-generation brewer), took over reins of the brewery in 1970, to help preserve the tradition of Belgian lambics and gueuze. Their son, Jean Van Roy, is now Cantillon’s brewmaster. Brasserie Cantillon produces 4,00,000 bottles of beer a year, with an alcohol content of 5%.

Extensive menu

It was only in 1999 that Brasserie Cantillon – the lone survivor from among 100-odd breweries around Brussels – shifted to using organically certified ingredients. In a bid to preserve the natural environment, spider webs are permitted to thrive between ageing barrels – they prey on unwanted insects!

Gueuze: This is a blend of new and older lambics (up to 2 years old), with secondary fermentation still underway in the bottles. This beer can last many months in a good cellar.

Kriek: Once a year, a batch of Kriek is produced using 150 kg of sour Schaerbeek cherries with 500 litres of beer, after soaking them for five months. Young lambic is added before bottling to obtain secondary fermentation.

Cuvée Saint Gilloise: This is not a traditional ‘gueuze’ because it is made from only 2-year-old lambic and is not a blend. Hallertau hops are cold-soaked in the cask for three weeks. With its natural carbonation in the bottle, the beer combines the lambic’s acidic taste with the bitterness of the hops.

For its fruit-flavoured beers, Brasserie Cantillon fills empty casks with various fruits and macerates them for three months to dissolve them. Young lambic is added to supply sugar for fermentation. Beers with raspberries are called Rose de Gambrinus; those with Bergeron apricots are called Fou’foune; and those with Muscat grapes are named Vigneronne.

In addition, lambic with soaked Merlot grapes from Bordeaux region of France gives birth to Saint-Lamvinus beer; Saaz hops give Iris beers a slightly bitter quality; and Mamouche, Nath and Soleil de Minuit beers come from lambics soaked in elderflower, rhubarb and cloudberry respectively.

Grand Cru Bruocsella: This is a 3-year-old lambic selected for its exceptional colour, flavour and taste, which does not undergo secondary fermentation in the bottle – according to Claude, it is considered the “missing link between beer and wine”.

Ancient recipe

Cantillon’s lambic is an ancient recipe of beer, notes the tour guide, Floris Pierre. Lambics go back to a time before humanity knew about microbiology, and fermentation was a mysterious gift from the gods.

Beers were fermented via “spontaneous fermentation”: natural ambient yeast that was floating in the air would settle into the wort and spark fermentation. The air would deposit a mix of brewing yeast, wild yeast and bacteria. Additionally, the oak from the barrels plays host to a whole variety of beer-loving microbes that contribute to the beer’s development and maturation.

Brasserie Contillon brews lambic only during the cold months (October to April) when the best mix of wild yeast is in the air and more dangerous bacteria are inactive.

Cantillon beers are traditionally served in wicker baskets, with the bottle lying sideways. The idea here is similar to resting sparkling wine on lees. Storing the bottles upright causes the cork to dry out and let all the carbonation out.

“It also keeps the yeast and other materials within the liquid from being agitated – and keeps them out of your glass!” notes Floris.

Brass tacks

The Cantillon brewery sources its raw wheat from Walloon and Flemish Brabant regions of Belgium. The barley is malted to when it begins producing enzymes that convert starches into fermentable sugars during brewing.

The crushing machine grinds the wheat and barley – but if it is ground too fine, it hampers filtering; and if is too coarse, it reduces yield. The rule of thumb is using 65% barley and 35% wheat.

So each time the mashing tun is in operation it means 850 kg of barley and 450 kg of wheat have been soaked in 5,000 litres of boiling-hot water. Within 2 hours the mash temperature has risen from 45-degrees C to 75-degrees C, by which time the starch in the cereals has converted into fermentable sugars.

After decanting, another round of mashing follows with another 5,000 litres of boiling water, to extract the maximum out of the wort. After filtering, the wort is pumped into the hop boilers on the first floor. The dregs in the mash tun, called “draff”, is sold as animal fodder.

About 2,000 litres of wort is pumped into two copper boilers, where 25 kg of 3-year-old hops are added to every 10,000 litres of liquid. Another 4 hours of cooking sterilises the liquid. Due to evaporation of about 2,500 litres of wort, higher concentrations of sugar are achieved, says Floris.

After filtering out the hops, the remaining 7,500 litres of wort is pumped into a cooling tun on the third floor. Called the “coolingship”, each part of this large copper vessel is riveted (no welding), making it a coppersmith’s masterpiece, according to Floris.

This a crucial part of the fermentation process, where the cooling wort comes in direct contact with ambient air, wild yeast and other beneficial microbes. To control the cooling, operators at the brewery can open or shut the ventilation shutters and allow the cool night air to cool the wort to about 20-degrees C.

The cooled wort is transferred to the fermentation vats of steel. Here it is determined how much of the sucrose extract will turn into alcohol by the fermenting agents.

The beer is then transferred into 225-litre or 500-litre oak or chestnut barrels, where it matures for over 3 years. Wood is essential for the liquid to exchange gases with the ambient air; so casks that have been used by wine or Cognac makers are used for fermentation.

Birth of gueuze

The wild yeasts react with the sugars, and in the first few days the fermentation can even be violent: the barrels are not sealed for a week for fear they might explode with CO2 build-up, according to Floris. Slow fermentation begins about a month later, and the barrels are then hermetically sealed.

Lambic makers do not top up their barrels to make up for evaporation. After 3 years of maturing in the barrels about 20% of the liquid is lost to evaporation. However, to protect themselves, some strains of yeast form a film that completely separates the beer from the air in the barrel!

The matured lambic is pumped into steel tanks after going through several cellulose filters to keep out dead yeast and other particles. It is then packed in wine-type bottles.

In the cellars, sugars present in young lambics initiate secondary fermentation and produce CO2. From a flat beer, lambic turns into a foaming one – and that is where gueuze is born!

Like any liquid matured in wood, lambic does not foam. The sugar content in a 3-year-old lambic has been reduced to 0.2%. Its acid taste and unique flavours make it a complex product.

“Lambic can be drunk after a few weeks,” says Jean-Pierre, “but we wait a full year to have a more refined beer, which can be used to make our gueuze, kriek, etc.”

Jean-Pierre and Claude have brought their son Jean and daughters, Magali and Julie, into the business. Along with their grandson, Florian, Jean-Pierre and Claude’s family continues to make Cantillon beers from some of the truly authentic lambics in the world. Brewers worldwide owe Brasserie Cantillon a ‘Hurrah!’ for persevering with this super-human endeavour and preserving a unique way of life.