On his quest to become a chemical engineer in the mid-1990s, Gumer Santos needed a quiet place to study. His friend invited him to the Trappist abbey near the small town of Rochefort, about 70 miles southwest of Brussels, in the Belgian province of Namur. There, he could focus on his studies over five years.
“It was perfect,” Santos says. “There was no stress.”
That was nearly three decades ago—and for much of the time since, Santos has been in charge of producing some of the best-regarded ales in the world at the abbey’s small brewery. Nestled in a peaceful location amid hills and trees and next to the abbey’s own chapel, it produces the kinds of beers that inspire quiet contemplation.
They include the complex dark ales known as Rochefort 6, 8, and 10, which increase in richness and strength, plus the Triple Extra—introduced in 2020, the abbey’s first new beer in 65 years.
The Dark Ales
The red-capped, mahogany-colored Rochefort 6 is the oldest of the abbey’s beers, introduced in 1950. It’s also the lightest in strength—but that’s only relative‚ as it’s still a beer of 7.5 percent ABV, with a starting gravity of about 1.072 (17.5°P).
The green-capped Rochefort 8, meanwhile, is a top seller locally and can be found in many cafés and restaurants across Belgium; its starting gravity is about 1.079 (19.1°P), with an ABV of 9.2 percent.
Finally, the Rochefort 10 with its blue crown cap is the strongest and most revered—a barleywine-strength Belgian ale of 11.3 percent ABV, with a starting gravity of about 1.096 (22.9°P).
All three of the dark ales get a pilsner base plus some medium crystal malt and cassonade sugar—a type of dark golden sugar typically made from beetroot. It’s popular among Belgians, who often add it to crepes or desserts.
“Our supplier asked us why we don’t use other sugars,” Santos says. “We made a small test batch, but the beer was not the same.”
A signature component of Rochefort’s beers is an attenuation approaching 90 percent, preserving a lighter body and drier finish despite their strength. The pilsner malt and sugar set the stage for that, but so does an efficient mashing process meant to maximize fermentability. The abbey brewery installed a new, larger brewhouse in 2020—more on that below—and it includes a mash press that meant making some adjustments. Broadly, Santos recommends a patient mash regimen with plenty of time in the beta-amylase zone—144–150°F (62–66°C).
Notably, Santos also cautions against using too much sugar: “The yeast will become lazy,” he says.
In the book Brew Like a Monk, published in 2005, Stan Hieronymus reported that Santos brewed with wheat starch—and that they had previously used maize—to prevent the beer from becoming “too thick.” Today, however, Santos says they no longer add wheat starch. “It’s not necessary with this type of mash filter,” he says.
Santos says he’s not exactly sure why the monks originally added the starch. “I think for historical reasons,” he says, “maybe economic reasons, long ago.” It’s long been common for Belgian brewers to add adjuncts that lighten the body as well as defray the cost of malt. “I think today, it’s better to have good malt in the recipe. It’s good for the foam, for the fermentation, for everything.”
For hops, the dark ales today receive a single addition of Aramis, a French variety released in 2009, at the beginning of their 60-minute boil. The target bitterness ranges from about 18 IBUs for the 6 to 27 for the Rochefort 10.
The brewery previously used classic Noble varieties—including Hallertauer and Styrian Goldings, per Hieronymus in 2005—but Santos says their previous suppliers were facing difficulties because of climate change. However, Hop France has been a strong partner for the brewery in recent years, he says, able to consistently deliver the quantity and quality needed for Rochefort’s beers.
There is another key ingredient, of course: water. Santos says the brewery’s own water is “phenomenal” because of its mineral content and the stability of that content year-round. “We have sulfates, chloride, a lot of calcium, and a little zinc,” he says. (The abbey fought and, in 2021, won a years-long legal battle to protect their water source from the expansion of a nearby lime quarry.)
For fermentation, Rochefort has long used its own characterful house yeast strain. Interestingly, recent genetic sequencing studies have found it to be a close relative of British ale strains. The culture is hardy, handling beers upward of 11 percent ABV without a problem. It’s also distinctive and largely responsible for the unique flavor profile of Rochefort’s beers. Santos says they can repitch the yeast from batch to batch weekly for up to six months without culturing up a fresh pitch.
“The yeast is very unique, with intense, spicy, and fruity aromas,” Santos says. The dark ales also get a slight touch of coriander, and it’s subtle—one would be hard pressed to taste it in the finished beer.
The brewery chills the wort to about 68°F (20°C) and ferments at 70°F (21°C) until completion. It takes only about five days for the Rochefort 6 and 8 to complete primary fermentation, while it may take the strongest one six to 10 days. The new Triple Extra also takes about six days, Santos says. After fermentation and before bottling, they step the beer down to near-freezing temperatures over three to four days.
Besides the new brewhouse, Santos also credits the reduction of oxygen at “every part of the process” for improvements in Rochefort’s beers. Two key changes, he says, were to mill the grains immediately before brewing and to add a drop of water when filling bottles, which helps to keep out oxygen as the beer foams.
For clarity, Rochefort’s beers also take two trips through the centrifuge: one after the boil to remove some of the hop particles, and another just before bottling to remove yeast. Afterward, the team adds a bit of fresh yeast—the same strain used to ferment—before bottle conditioning for two to three weeks to a lively 3.75–4 volumes of CO2.
A New Beer, a New Brewhouse
Santos says the circumstances that led to brewing the new Triple Extra—the brewery’s only pale beer—were threefold.
First, tripels and other strong blonde ales are popular in Belgium, so there has been demand for years. “People were always asking when we would do a blonde beer,” he says.
However, the old brewhouse was at full capacity to meet demand for the dark ales. The 2020 upgrade removed that constraint, and the new brewery has an annual capacity of about 76,000 hectoliters (64,000 U.S. barrels); they’re currently using about two-thirds of that.
Finally, Father Abbot Gilbert Degros was preparing to retire after years of leading the monastery, and he was open to releasing a new beer as part of his legacy.
Santos describes an excitement that surrounds the new beer locally and around Belgium. “It’s rare to make something new here,” he says. It’s been a success so far, Santos says, growing steadily in sales but not outpacing the 8 or the 10.
For test brews to develop the recipe, he purchased a small 20-liter system and began experimenting. “We made 20 different recipes to progressively arrive at the final beer. It was a team adventure—everyone gave ideas.”
Of course, that small system isn’t the same as the new brewhouse, and 20-liter tanks can’t replicate the fermentation characteristics of larger systems’ 25-foot fermentors. However, the small-scale tests gave them the chance to compare ingredients. “It helped us select one hop versus another, or one spice versus another,” Santos says, “even if it was not the exact same beer.”
The final recipe is about 90 percent pilsner and 10 percent wheat malt, both from Dingemans. “The wheat malt provides some turbidity—it’s cloudy, like a white beer,” Santos says. The beer receives two hop additions for bittering and aroma. It also gets Alsatian hops, but not Aramis—instead it gets a different aromatic variety that contributes delicate tropical-fruit and floral notes. (Santos prefers not to specify which variety.) The beer also gets a touch of sweet-orange peel in the boil.
The new brewhouse replaced one that had been in operation since 1962. The monks and Santos selected it for two reasons: It’s highly efficient, and it’s from a Belgian company—the same one that built the previous brewery.
“Meura built our previous brewhouse,” Santos says. “They have good local people who speak our same language.”
In particular, Santos points toward the new mash filter as a key component. “We wanted to use this technology,” he says. “It’s important to have efficiency in the equipment.” That trait, in combination with the use of solar energy, helps to reduce the brewery’s environmental impact.
Santos says the transition to the new system wasn’t overly difficult because the team took its time moving from the old one. For six months they brewed on both systems before fully moving to the new one. Still, it was a careful process that prioritized quality and consistency as they moved from the older copper brewhouse to the new stainless one. “We were blending batches” from both brewhouses, he says. “And the first thing we said is, ‘If the beer is not okay, we’ll throw it away.’”
Besides the mash filter and size, they found another difference in the new system: The ales now ferment more quickly than they did before. The tank geometry is different, with fermentors that are about the same height as the old ones but not as wide. The team also altered the oxygenation rates and lowered the fermentation temperatures to achieve consistent results.
They also found that they were able to simplify the recipes of the legacy dark beers—the 6, 8, and 10—thanks to the new system’s efficiencies, Santos says, and based on side-by-side batch comparisons.
Time to Enjoy
There is some debate within the brewery over the best age at which to drink Rochefort’s dark ales.
Some prefer them as fresh as possible; Santos says he likes them best at about six months. “It’s like when you eat spaghetti bolognese,” he says. “After one day, it is not the same.” And so it is with Rochefort 6, 8, or 10 after some months in the bottle. “The mixed aromas are more complex, more melded.”
However, he says, everyone can agree that the Triple Extra tastes best fresh “because the aromas are so delicate.”
Unlike the dark beers, the Triple Extra is available on draft. Typically carbonated to about 2.5 volumes in the keg, it provides a different experience than the bottled ale. “The bottle has more body; it’s better to taste slowly,” Santos says. “The keg is more ‘green’—you feel the aromas of the hops more.”
The abbey isn’t planning to develop any other new beers, nor is it planning to increase its volume. If the monks want to make more beer, Santos says, they can do so. But the abbey’s focus is on sustaining its existence and contributing to the community—not maximizing profits at every corner.
It’s a refreshing perspective that fits the brewery’s commitment to excellence as well as its quiet, peaceful setting.
