Belgian Dark Strong Ale (Quadrupel)


Belgian Dark Strong Ale (Quadrupel)



For many the Belgian Dark Strong Ale style (also known as Belgian Quadrupel) is the holy grail of beers. The strongest and boldest of the Trappist beers, think of it as a mixture of a Dubbel's flavour profile and hue with the high alcohol content of a Tripel, both taken up a notch or two. It's a rich and flavourful beer, adored by many. To quote the Beer Judge Certification Program (BJCP) style guidelines:

A dark, complex, very strong Belgian ale with a delicious blend of malt richness, dark fruit flavors, and spicy elements. Complex, rich, smooth and dangerous.

Brewers will spend years trying to perfect their recipe, often trying to mimic complex Trappist beers such as St. Bernardus Abt 12, Westvleteren 12, or Rochefort 10 that have been brewed for decades by monks who have perfected their art. (The numbers represent an archaic way in which Belgians measured original gravity).

From left to right: St. Bernardus Abt 12, Westvleteren 12, and Rochefort 10 Belgian Dark Strong Ale beersFrom left to right: St. Bernardus Abt 12, Westvleteren 12, and Rochefort 10. Image (c)

Our recipe here has been heavily inspired by Westvleteren 12 (Westy 12 as it's known by fans). While we wouldn't necessarily call it a clone, if you're a fan you'll definitely like our version.

The resulting beer is rich and full, almost creamy with hints of dark stone fruit, currants, and molasses. Complemented by an underlying spiciness and caramel sweetness. The high gravity provides a nice warming effect without being solvent-y. Smooth and complex, best sipped slowly and savoured.

Westy 12 is a beer that has garnered a somewhat cult following over the years especially after having been named best beer in the world more than once, first time in 2005. This world attention caused the already highly sought after / low production output beer to all of a sudden go from 'hard to get' to 'impossible to get'. Even before being tagged as the best beer in the world, your order had to be placed ahead of time through the abbey's phone system and picked up on location. Good luck getting through now with the abbey receiving nearly 100,000 calls/hour.

Patrons line up at the abbey to pick up their Westvleteren beerPatrons line up at the abbey to pick up their Westvleteren beer. Image (c) Morner /

Cases of Westvleteren 12 ready to be loadedCrates of Westvleteren 12 ready to be loaded. Image (c)

Today the beer is still only sold locally at the abbey to patrons who were fortunate enough to successfully reserve through the website (the phone system was retired in 2019). Orders have to be placed in advance, sometimes weeks or months ahead of time, and are limited to three crates of 24 bottles no more than once every 60 days. The limited quantities help ensure fairness and eliminate commercial reselling.

As the beer is not (legally) exported or sold elsewhere, the bottles are not even labelled. Everything that is required by local law is printed directly on the cap.

    Westvleteren beer caps including Westvleteren Blonde, Westvleteren 8 (Dubbel), and Westvleteren 12 (Quadrupel)Clockwise from top: Westvleteren Blonde, Westvleteren 8 (Dubbel), and Westvleteren 12 (Quadrupel). Image (c) WaltYs /

    The brewery produces three beers, each with a unique cap colour:

    • Green: Westvleteren Blonde, 5.8% ABV
    • Blue: Westvleteren 8 (Dubbel), 8% ABV
    • Yellow: Westvleteren 12 (Quadrupel), 10.2% ABV

    Since 1946 the brewery has only produced 4000 barrels/year, the lowest output of all the Trappist abbeys. By comparison, Chimay produces the most at just over 100,000 barrels/year. 

    So why not increase production to meet demand? The reasons are simple: The abbey is fiercely against it as they only brew enough beer to run the monastery, and will not make more than they need to sell, regardless of demand. "We are no brewers. We are monks. We brew beer to be able to afford to be monks," states Father abbot on the abbey's website.

    Saint-Sixtus Abbey of WestvleterenSaint-Sixtus Abbey of Westvleteren. Image (c) Bernt Rostad /

    Westvleteren brewhouseWestvleteren brewhouse. Image (c)

    Open fermentation at Westvleteren breweryOpen fermentation at Westvleteren brewery. Image (c)

    Westvleteren brewery bottling lineWestvleteren brewery bottling line. Image (c)

    Enjoying a Westvleteren 12 at the In de Vrede cafe across from the abbey, the only location authorized to serve Westvleteren Trappist beerEnjoying a Westvleteren 12 at the 'In de Vrede' cafe across from the abbey, the only location authorized to serve Westvleteren Trappist beer. Image (c) Jerman JMC /

    So with this extremely limited supply through basically a lottery system, long lead times, and zero (legal) export, what's a homebrewer to do? Simple! Brew it yourself!

    Through excellent books such as Brew like a Monk and the internet it's fairly straight forward to figure out what goes into the beer and most of the process that is used. But like any good homebrewer we couldn't leave well enough alone and made some minor tweaks to suit our preferences.

    Our version is slightly stronger (11% ABV instead of 10.2%), uses only pilsner malt instead of a mix of Dingemans pale and pilsner, and one hop substitution (Saaz instead of Hallertau) as we find the subtle spiciness pairs well with the yeast.

    As much as you research there are certain pieces of the puzzle that will likely always remain a secret that we have to account for. This includes how the Westvleteren brewery treats their water. Their water is known to be fairly hard and the brewery has mentioned it's treated. How exactly is anyone's guess, but like our other Trappist recipes, for this one we've gone for a balanced approach as it works well for the style. How the brewery produce the darker colour and flavours is the biggest unknown, but it's most likely done through darker candied sugars or syrups so that's what we've included here. For more information on the ins and outs of the Westvleteren brewery refer to the book Brew like a Monk.

    We've brewed a few different Belgian Dark Strong Ale recipes over the years, and while all turned out well it's ultimately the simpler recipe presented here that we've enjoy the most. The biggest change from previous versions is that this recipe focuses on getting most of the colour and a large portion of the special flavours from candied sugar, in this case Belgian candi syrup (extra dark D-180).

    Belgian candi syrup (extra dark D-180)Belgian candi syrup (extra dark D-180) ready for our Belgian Dark Strong Ale brew day.

    In the past we've tried using crystal malts such as Dingemans Special B and Weyermann CaraMunich Type III as found in our Dubbel, in combination with candied sugars. We found that the unfermentables from the crystal malts boosted our final gravity farther than we liked so this version doesn't use any crystal malts at all. The goal was to hit the same 86% attenuation as Westvleteren.

    Why is this important? This lack of remaining sugar ensures that even the highest gravity beers are not cloyingly sweet. Many Belgian beers (including this one) finish surprisingly dry given the very high starting gravity. Belgian brewers like to use the term 'digestible', meaning that their beers are highly attenuated making them easy to drink in quantity. Well, maybe not this 11% ABV beer but you get the idea. 😉

    This proper attenuation is critical to brewing a high gravity beer correctly. If you've brewed some of our other recipes and your beers are not attenuating per the recipe, best to leave this Belgian Dark Strong Ale until you've honed your skills. The most common reasons for under-attenuated beers are under pitching yeast and/or not providing enough oxygen (see our Making a Yeast Starter and Aerating / Oxygenating Wort guides for how to ensure success every time). Both are critical when brewing higher ABV beers such as this. Fluctuating temperatures during fermentation, especially dropping temperature during fermentation, can also cause yeast to stall. The multi-step mash schedule outlined in our recipe also helps maximize wort fermentability which increases attenuation.

    Yeast choice for this beer is the Westmalle yeast which is available as White Labs WLP530 Abbey Ale or Wyeast 3787 Trappist High Gravity. Westmalle cultivates this yeast in-house and shares with other Trappist breweries including Westvleteren so this was an easy choice. It's very alcohol-tolerant (up to whopping 15% ABV) and famous for producing very smooth, drinkable beers that are both flavourful and boozy. Expect spice and fruit flavours (plum, raisins, pear, and apple). 

    Unlike Westmalle who pitches at 64F and allows fermentation to only rise to 68F, Westvleteren pitches this yeast slightly warmer at 68F and allows it to reach as high as 82-84F to promote the spicy phenols and fruity esters. Fermentation schedule and temperature plays an important role in creating different flavour profiles so heed the instructions in our Notes / Process section below.

    Given the true top cropping (fermenting) nature of the yeast, also make sure to have a good 20-30% of headspace in your fermenter. A blow-off tube is recommended (see the videos in our Pictures / Videos section below).

    Belgian Dark Strong Ale is a style that deserves a bit of cellaring before consuming. Try and tuck some of it away for at least 4-6 months. At the time of this writing ours has been packaged for 8 months and it's interesting to see how it has changed over time. It can easily be aged for years.

    For serving, it's best to use a Trappist goblet or chalice (see picture at very top). This does full justice to the complex character of the beer and allows room for the rich head. Like any other pour, ensure that the glass is free of any detergents or grease as either will cause the foam to immediately disappear. If you keg like we do, make sure your lines are clean as deposits affect both flavour and head retention (see our Cleaning Beer Lines guide). 

    For those that like to bottle, keep the beer in a dark place at a constant temperature somewhere between 46-56F once carbonated. Before serving, let the bottle rest cold for at least a week so that the yeast sinks to the bottom and you will get a nice clear pour. The beer should be clear, not cloudy. When pouring, hold the glass at an angle and begin pouring slowly along the side. Continue pouring in one movement and hold the glass vertically at the end in order to end in the middle, producing a perfect head. Leave around half an inch of beer in the bottle. This yeast base (rich in vitamin B) can be consumed separately.

    Brew up a batch and let us know how you like it!


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    Belgian Dark Strong Ale (Quadrupel)

    Size: 12 US gallons (post-boil @ 68F)
    Mash Efficiency: 90% (lower due to the high gravity)
    Attenuation: 86%
    Calories: 319 kcal per 12 fl oz
    Original Gravity:
    1.096 (style range: 1.075 - 1.110)
    Final Gravity: 1.014 (style range: 1.010 - 1.024)
    Colour: 23.3 SRM (style range: 12 - 22)
    Alcohol: 11% ABV (style range: 8% - 12%)
    Bitterness: 36.2 IBU (style range: 20 - 35)

    32.2 lb Belgian pilsner malt (1.4-1.8L)* (85.4%)

    2 oz German Northern Brewer hops (8%) - added during boil, boiled 60 min [25 IBU] 
    2.5 oz Czech Saaz hops (3.2%) - added during boil, boiled 20 min [7 IBU]
    1 Whirlfloc tablet (Irish moss) - added during boil, boiled 15 min
    5.5 lb Belgian candi syrup (extra dark D-180) (14.6%) - added during boil, boiled 10 min (add slowly)
    2.5 oz Styrian Goldings hops (2.7%) - added during boil, boiled 10 min [4.2 IBU]

    Wyeast 3787 Trappist High Gravity yeast or White Labs WLP530 Abbey Ale yeast
    (~1040 billion cells [10-11 fresh packs] or an equivalent starter)

    *Can't find Belgian pilsner malt? German pilsner malt (1.5-2.1L) will make an excellent Belgian Dark Strong Ale as well.

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    Notes / Process

    • Water treated with brewing salts to our Balanced flavour profile: Ca=50, Mg=10, Na=16, Cl=70, SO4=70 (Hit minimums on Ca and Mg, keep the Cl:SO4 ratio low and equal. Do not favour flavour / maltiness or bitterness / dryness. For balanced beers.). For more information on how to adjust your water, refer to our step by step Water Adjustment guide.
    • 1.25 qt/lb mash thickness.
    • Start the mash at 131F and hold for 10 mins (high end of the protein rest range).
    • Ramp up to 149F and hold for 90 mins (beta rest).
    • Ramp up to 155F and hold for 30 mins (alpha rest).
    • Raise to 168F mashout temperature and hold for 10 mins.
    • If your system does not allow for step mashes, try a single infusion mash at 150F for 90 mins, followed by a mashout to 168F for 10 mins (if possible).
    • ~90 min fly sparge with ~5.6-5.8 pH water (measured at mash temperature).
    • Boil for 90 minutes, adding Whirlfloc, hops, and candi syrup per schedule. Lid on at flameout, start chilling immediately.
    • Cool the wort quickly to 66F (we use a one-pass convoluted counterflow chiller to quickly lock in hop flavour and aroma) and transfer to fermenter.
    • Oxygenate the chilled wort to a level of 14 ppm dissolved oxygen. Given the high starting gravity, a second dose to 14 ppm is recommended approximately 12-18 hours after the yeast has been pitched. For more information refer to our Aerating / Oxygenating Wort guide.
    • Pitch yeast and ferment at 68F (wort temperature), allowing temperature to rise naturally as high as 82-84F but no higher (do not allow to rise more than 1 degree per day). Do not fret if yours doesn't want to go this high. We use modified stainless fermenting buckets in wine fridges.
    • Allow yeast to continue until finished. Do not allow temperature to drop as it can cause the yeast to stall. Assume fermentation is done if the gravity does not change over 4-6 days.
    • Rack to a brite tank (we use 5 gallon glass carboys) that has been purged with CO2 to avoid oxygen pickup, add 1 tsp of unflavoured gelatin dissolved in a cup of hot distilled water per 5 gallons of beer, and allow to clear for 2-3 days. Westvleteren does not filter or use clarifiers in their beers so you may wish to skip this step. The beer will drop brilliantly clear on its own during the conditioning period. As well, the less you handle the beer through racking and potentially expose it to oxygen, the better.
    • Package as you would normally. Though some will argue that a Belgian Dark Strong Ale should only be bottled, if we still had to bottle we wouldn't be brewing beer. 😉 We rack to kegs that have first been purged with CO2 and then chill the kegs to near freezing while carbonating at the same time in a 6-keg conditioning fridge. After ~1-2 weeks at serving pressure the kegs will be carbonated and ready to serve. In a hurry? Feel free to raise the CO2 pressure temporarily to 30-40 PSI to carbonate fast over a 24 period, and then turn back down to serving pressure. 
    • Carbonate this beer to higher than normal levels, around 2.5 to 3.5 volumes of CO2.
    • The beer will improve if conditioned just above freezing for 8-10 weeks before serving or cellaring, and will continue to change over time. Sampling is recommended.

    For detailed brewing instructions, see our Brew Day Step by Step guide.


    Questions? Visit our Belgian Dark Strong Ale (Quadrupel) forum thread


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    Pictures / Videos

    Interested in seeing what we're brewing right now? Follow us on Instagram for pictures and videos of our brewing activities as they happen.