Decoding the world of lambic beers

It’s a curious phenomenon that lambic beer, now a cult beer internationally1, has been largely overlooked in its native Belgium since the 1960s. Yet, an international revival has emerged following the rise of natural wines that began in France during the 1990s. Lambic beers, known for their spontaneous fermentation process, are often perceived as purist or as employing minimal intervention, akin to the ethos of natural wines. This brewing method utilises wild yeasts, including bacteria like Brettanomyces and Pediococcus alongside the more common Saccharomyces cerevisiae, imbuing the beer with a distinctive acidity, sometimes funky aromas and a certain volatile acidity—qualities shared with some natural wines.

Table of contents
1. What is a lambic?2. How does lambic taste?3. Types of lambic
4. History5. How is lambic made?6. Our collection of tasting notes
7. Visiting Cantillon and 3 Fonteinen

What is a lambic?

A lambic is a spontaneously fermented beer made from a mash of 60 to 70% pale two-row barley malt, 30% to 40% raw wheat and aged hops. Unlike conventional beers, lambics do not rely on manually added yeasts. Instead, they embrace the wild yeasts present in the environment, allowing these natural elements to inoculate the brew. The fermentation is done in oak foudres and is traditionally confined to the cooler months from October to May, allowing for natural temperature control of the process. While its production is theoretically2 confined to the Pajottenland region and Brussels, no one will stop you from applying the principles of lambic brewing elsewhere to make your own beer.

How does lambic taste?

The result of this very particular brewing method is a clear pale yellow beer, with a very vertical acidity and alcohol levels around 6% ABV. Aromas tend to range from apples, citrus, white flowers and apple cider, vanilla from oak to apricots, candied lemon, hazelnut, yeast, biscuits and bread when aged over 10 years in the bottle. Even though Brettanomyces, Pediococcus and enteric bacteria are involved in the fermentation, most beers tend to be fairly clean. Nonetheless, funky aromas are also possible, with notes of animal, sweat or vinegar.

For more detailed tasting notes, see our table of tasting notes below.

Types of lambic

Finding pure, unblended lambic can be challenging; it’s often only available on tap directly at breweries. Instead, it is primarily sold as a derivative product:

  • Faro: A young lambic, sweetened with brown sugar or molasses, generally featuring a healthy fizz, unless it has been pasteurized.
  • Gueuze: A blend of young and old lambic, typically aged from one to three years in foudre. The younger lambic’s sugars promote refermentation in the bottle, resulting in a moderate effervescence when served.
  • Fruit lambic: A lambic macerated or blended with fruit or fruit juice and allowed to referment in bottle to yield a moderate fizz when served. The most common fruit used is sour cherries (kriek).


The history of lambic beer is shrouded in uncertainty, with mixed accounts and no consensus on its origins. Part of this lack of clarity can be attributed to the decline in the popularity of lambic during the 1970s, which led to a loss in oral histories and accounts, further compounded by the absence of early records. The reliable information on lambic can be found through the HORAL collective of lambic brewers, writer Jef van den Steen3 and Raf Meert’s comprehensive treatise Lambic. The Untamed Brussels Beer: Origin, Evolution and Future. Although Meert’s work has not been peer-reviewed, it remains the most comprehensive analysis available, providing substantial documentation for its hypotheses. We have drawn primarily from his book for our summary below.

Contrary to popular belief supported by HORAL that lambic dates back to the 13th century, the earliest documented mentions of lambic are found only in the late 18th century. Meert reveals several references to lambic during this period, all within the city of Brussels. The story of gueuze is equally veiled in mystery. Meert, however, pinpoints the first mention of ‘gueuze lambic’ in barrels, dating back to an 1831 property inventory near Brussels.

The current form of gueuze, a blend of various aged lambics bottled together, did not emerge until the late 1800s. This period saw increased demand for effervescent beers. In response, lambic blenders experimented with carbonation methods, culminating in the practice of blending young and old lambics for bottle refermentation, established around 1900. This technique, similar to the méthode champenoise used in Champagne production, now stands as a hallmark of gueuze production.

Cantillon’s copper cooker.

By the First World War, there were hundreds of lambic producers, including brewers and blenders. However, the war led to a significant decrease in production, as many closed or had their copper brewing equipment seized. The Second World War further exacerbated this decline and in the subsequent post-war era, consumer preferences shifted towards heavier beers like Trappist dubbels4 and tripels. By the 1970s, lambic had fallen out of favour, perceived as outdated. This prompted producers to adapt by introducing sweet fruit lambics to appeal to tastes influenced by the sweetness of American soft drinks. Recently, however, the rising popularity of natural wines in Paris has sparked renewed interest in these spontaneously fermented beers. Over the past 20 years, the industry has seen a modest revival, growing from twelve to seventeen producers, comprising twelve brewers and five blenders.

How is lambic made?

Lambic brewing begins with milling malted barley and unmalted wheat grains. The grains then undergo a turbid mashing process, which extracts both simple sugars and more complex starches. These starches are not digestible by the common yeast Saccharomyces cerevisiae, enabling prolonged fermentations lasting years, supported by other yeasts and bacteria.

After mashing, the wort is boiled to sterilize it. The process typically lasts a few hours. At this point, hops aged for one to two years are introduced. During this ageing process, the hops lose some bitterness while retaining their preservative properties. Because they add minimal flavour, it’s possible to use them in larger amounts.

The wort is then left to cool to room temperature overnight exposed to open air in large copper vats called coolships. The yeast and bacteria from the surrounding environment, developed symbiotically over years of lambic production in the brewery, naturally inoculate the wort. The next morning, the cooled liquid is transferred to oak barrels, where it ferments throughout the winter at approximately 10°C.

Coolship in Brasserie Cantillon’s attic.

Normally, Saccharomyces species are preferred for brewing high-quality beer, while Brettanomyces, Pediococcus and enteric bacteria are typically viewed as contaminants, negatively impacting beer flavour. In lambic, Saccharomycescerevisiae and Saccharomyces bayanus dominate the alcoholic fermentation only for the first few months. Certain enteric bacteria produce some acetic acid in this phase. Following this, the Pediococcus species take over, producing lactic acid during the warmer months and reducing the beer’s pH to about 3. It is around eight months into the process that Brettanomyces strains start to dominate, consuming the remaining complex starches. This process not only increases the alcohol content but also significantly alters the beer’s flavour, adding savoury notes.

Brett and acetic acid are not as detrimental as in winemaking

In the context of winemaking, Brettanomyces and acetic acid are often considered undesirable, but in lambic brewing, these elements are not as harsh as long as they remain in moderate concentrations. On the other hand, improper barrel handling can lead to undesirably high levels of acetic acid. This is particularly true if there’s excessive oxygen exposure, either due to evaporation or a breach in the insulating yeast coating on the barrel walls.

Making gueuze and fruit lambic
Gueuze bottles waiting to finish their second fermentation before being labelled.

Gueuze is made from a blend of lambics aged in oak barrels for different lengths of time. The best producers typically combine one-year-old, two-year-old, and three-year-old lambics in roughly equal measures, and some even include four-year-old lambic. The skill of the blender lies in selecting and combining barrels to achieve a desired structure and flavour profile, since each barrel will ferment differently and have a distinct taste. The older lambics in the blend contribute to a more complex, nuttier, and rounder flavour, while the younger lambics bring a freshness to the blend. Importantly, these younger lambics still contain complex starches, such as dextrins. These are essential for the Brettanomyces yeasts to trigger a secondary fermentation in the bottle, creating the carbonation that is characteristic of gueuze.

The second fermentation stage lasts for about eight months. Due to the lack of temperature control in the cellars, this period must include a summer season, as warmer temperatures are crucial for the optimal development of these yeasts. When nutrients are depleted, the yeast cells die and undergo autolysis, creating distinctive yeasty flavours. Although Belgians proudly compare this process to the méthode champenoise, it differs by omitting the disgorgement of the bottle, a technique used in Champagne to remove the dead lees from the bottle. Consequently, if the consumer chooses to age the bottle further, these yeasty characteristics continue to evolve. In fact, thanks to its acidity, gueuze can easily age for 20 years in bottle.

Stainless steel vats employed for the maceration of fruit in lambic at 3 Fontainen.

On the other hand, fruit lambics are made by macerating fruit in young lambic. The highest quality versions are made with whole, intact fruit, but some brewers opt for juice, concentrates, or syrups. As fruit is typically harvested in warmer months, this leads to a rapid secondary fermentation. Brewers then age the resulting mixture in oak barrels for several months, after which it is usually filtered and blended with a third of young lambic to allow for a final fermentation in bottle, similar to the process used in gueuze. To fully enjoy the fruit character, some recommend consuming these lambics within the first two years of their labelling. Among the most traditional fruit lambics is the kriek, made from sour cherries, with those made from the nearly extinct Schaarbeek cherry variety being particularly coveted.

Our collection of tasting notes

Below we provide a comprehensive table of our tasting notes of lambic and its derivatives. Similar to our wine tasting notes, tasting in a systematic manner has been instrumental to develop our palate and our understanding of these unique beers. Our notes are categorised into distinct sections: aromas detected by the nose, aromas discerned on the palate, and the overall structure of the beer.

CantillonGueuze2022Very complex nose. Notes of vanilla from oak, green almonds, and yellow plums. A mild touch of acetic.Green apples, and yellow plum dominate over a tart citric note of lemon. Through the midpalate and finish, the vanilla rounds it up. Delicious, probably one of the best beers we have had.High acidity, dry, 5.5% alcohol, light body.
CantillonRose de Gambrinus2023Very aromatic with aromas of fresh raspberries, rhubarb and a touch of yeast.Fruity core of raspberry juice, with a large proportion of fruit per bottle. Good body and sweeter, which balances the acidity of lambik to a more tamed tension.High acid, medium sweet, 5.5% alcohol, medium body.
CantillonSang Bleue2022Very fruity tart red berries: mostly cranberries and red currants.The palate confirms the nose, with the midpalate showing lots of malic acid. Some notes of violets and mild acetic aromas.Very high acid, medium sweet, 5.5% alcohol, medium body.
CantillonSaint Gilloise2023Very different to the 2022 cuvée. Very aromatic, with very hoppy notes that would remind one of an IPA, just milder. In the background some lemon zest.More body than the Gueuze, with primary notes of lime and lemon and a mild yeasty finish that is dominated by the hops. Mild lemon pithy bitterness on the finish too.Very high acidity, dry, 5.5% alcohol, light body.
CantillonSaint Gilloise2022Relatively muted notes. Notes of lemon and green apples.Similar to Gueuze, but with a less ripe fruit and much less oak. Green apples a citric note of lemons and lime zest. Sharp, more for an aperitif?Very high acidity, dry, 5.5% alcohol, light body.
CantillonSaint Lamvinus2022Aromatic nose, but perhaps more unidimensional here. Plums from the Merlot and lemon zest of the lambic. Perhaps it needs more time for the Merlot to feel integrated into the beer.Confirms the nose. Good concentration of fruit. There is a note of oak in the finish that evokes a red wine note. But it did not feel like great quality oak, it reminded us more of oak chips.Very high acidity, low tannins, medium sweet, 7% alcohol, light body.
CantillonNath2023Medium intensity on the nose, there are some wafs of volatile acidity and Brett which are not very pleasant. Behind them we get some floral notes of rhubarb and apple skins.Cleaner than the nose. The oak is not very noticeable, giving a floral and green apple profile. The rhubarb notes shine through here. The acidity is surprisingly tamed for a lambic, very well balanced.High acidity, dry, 5.5% alcohol, light body.
CantillonGrand Cru Bruocsella2023Amber colour and medium intensity. The nose is more oxidative with notes of hazelnuts, apricot, raisins and a touch of leather.The palate shows a lot of body for a lambic, with a much milder toned-down acidity. The attack is driven by apricots, with the midpalate showing oak tannins that give a sensation of drinking an orange wine. Flavours of apple skins, apple cider and hazelnuts also show here. The finish is slightly honeyed.Crisp acidity, dry, 5% alcohol, medium body. Long finish.
3 FonteinenOude Gueuze (Blend 75)21/22Very aromatic. Notes of ripe pear and apple with a lot of influence from oak, but not overwhelming. It’s actually well integrated: cedar, vanilla, clove, toasted bread.More body and concentration than in Cantillon’s Gueuze. Ripe apples, apricot, and candied citrous would describe the fruit profile best. The oak notes do the rest with clove, vanilla, cedar and hay.Fine soft mousse, high acidity, dry, 6.7% alcohol, medium body. Very long finish.
3 FonteinenZenne y Frontera (Blend 66)20/21Wow, what a nose. Very aromatic and complex. There are notes of ripe apple and torrefaction (coffee or cocoa), mixed with ebony and Marsala spice. Swirling makes it even more complex, adding aromas of lemon zest to the mix.The complexity finds itself in the palate too. The attack is driven by apple and lemon, but quickly changes to the secondary notes of its élevage in the midpalate. The beauty is how well integrated these notes are. Simply delicious.Fine soft mousse, high acidity, dry, 8.5% alcohol, medium body. Very long finish.
3 FonteinenOude Gueuze Vintage2010Nose is quite developed and very aromatic. Notes of apricot and honey are followed by very autolytic notes that are reminiscent of Champagne: brioche, biscuits and sourdough. Very layered.No fizz left and more amber colour. Fermentation can continue overtime with Gueuze, so it’s good to see that the body is still there and plentiful. Notes of apricot, dried apricot are followed by candied lemon before a long autolytic finish. The usual tension and verticality of Geuze has been rounded by time into a softer version.

Fizz is almost imperceptible, high acidity, dry, 6% alcohol, medium body, very long finish.
3 FonteinenOude Gueuze Cuvée Armand et Gaston Vintage2019Very aromatic nose with a touch of VA that blows off with time. Green apple and lemon zest notes dominate after that.Beautiful tension and concentration, well balanced naturally. Pure and clean palate with green apple, lemon and lime zest.Fine soft mousse, very high acidity, dry, 6.6% alcohol, medium body. Long finish.
3 FonteinenOude Lambik (By the glass)Medium aromatic, lemon and lemon zest, quite bright.The palate is very fruit forward, lime and lemon juice with a long lemon zest and pith (a touch of pleasant bitterness) in the finish.Flat, high acidity, bone dry, 6% alcohol, medium body, long finish.
3 FonteinenFaro Klassik (By the glass)Medium aromatic with a precise nose of chestnut honey and buckwheat.The palate is fruit forward, lemon juice with oat porridge and a lemon zest and honey finish. More rounded than the lambics, the freshness is more polished, but it is also more full bodied. WeVery mild mousse, high acidity, off-dry, 6% alcohol, medium body, long finish.
3 FonteinenFramboos Oogst2019Very aromatic and complex nose. Funky, in a good way: sousbois, rhum molasses notes, vanilla from oak. All very well integrated. No acetic notes. Truly excellent.Here one can notice more the raspberries, but again very well integrated into the lambic. The result is similar to green apples and raspberries. The finish is closed by those great notes from the nose. Long finish.Fine soft mousse, high acidity, dry, 6.2% alcohol, light body.
3 FonteinenDruif Riesling (Blend 50)21/22Medium aromatic nose. Notes of citric hops and lemon. The oak influence here is less pronounced, fresher and fruitier, but still some vanilla and hay notes.Lighter and zestier, resembling more St Gilloise from Cantillon. Green apples, rhubarb and lime dominate. The finish shows that touch of oak.Fine soft mousse, very high acidity, dry, 6.7% alcohol, medium body. Very long finish.
3 FonteinenDruif Blaufränkisch (Blend 44)22/23Very aromatic nose for a very vinous lambic. Lots of fresh red cherries and cranberries. Only some mild yeasty notes remind us that this is a fruit lambic.Confirming the nose, this is a very vinous beer. The attack is led by cranberries and a vinous herbal note. It’s in the midpalate that one realises the sharper acidity and lighter body compared to a normal Blaufränkisch. Here notes of yeast, leather and cedar mix through the finish for a more savoury feel. One of the best fruit lambics we have tried.Fine soft mousse, high acidity, dry, 8.2% alcohol, medium body. Very long finish.
3 FonteinenHommage (Blend 33)18/19Very aromatic nose. The notes of fresh red cherries and raspberries are very forward. Mild yeasty and oaky notes round up the fruity aromas.Very very acidic, with the fructose of the red fruit not showing at all. A fruit forward attack followed by the deep acidity and some notes of oak.Fine soft mousse, very high piercing acidity, dry, 6% alcohol, medium body. Long finish.
3 FonteinenTuverbol2022Aromatic and hop-forward.A mix of blonde triple and lambic. The lambic gives some acidity, but it’s mostly driven by the grainy and fresh hops notes of the triple.Vigorous mousse, medium acidity, dry, 9.6% alcohol, full body.
BoonOude Gueuze Vat 312020Very aromatic nose, with notes of lemon and green apple, but also a very well integrated spicy oak, with notes of allspice that is different from the vanilla tones of oak from wine barrels.More power and body than a normal Gueuze, with an acidity that is better round off by the concentration. Beautiful notes of lemon zest, a touch of pith in the end as well as the spicy oak.Very fine soft mousse, high acidity, dry, 8.5% alcohol, medium body. Very long finish.
  1. Mainly France, Switzerland, Germany and the United States.
  2. References to the Belgian Royal Decree from May 1965 tend to indicate this, but the document online makes no mention of Pajottenland nor Brussels.
  3. Geuze & Kriek: the Secret of Lambic.
  4. Also a relatively recent invention, dating back to 1921 in Westmalle.

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