Cantillon Brewery


Jean-Xavier Guinard’s “Lambic”

Nothing is more suitable than to open a book about lambic beers with a personal story on how the author became acquainted with that most mysterious of beers. In the case of Jean-Xavier Guidard most people will recognize the experience. A young student in Paris is persuaded by his friend to order a Kriek, “a wheat beer from Belgium made by spontaneous fermentation and with macerated cherries.” After looking at the price on the board, the author is not so sure. His friends offers to buy it, and the rest is history.

Although the detailed technical discussion of brewing traditional lambics may be challenging to some readers, the complexities of this unique Belgian brew more than warrant the fascinating tour through the wonderful microbial flora that work together to create lambic. Because there are many basic introductions available about traditional lambic brewing, I will focus here on some of the more interesting details that the author has collected during his research.

The author starts off with a fascinating history of lambic beers and draws attention to the close similarities between traditional lambic and sikaru, a beer that was produced 5,000 years ago in Mesopotamia by Sumerians. A Sumerian tablet revealed that the basic composition of sikaru was virtually identical to that of lambic. Sikaru did not include hops but rather spices like cinnamon to add flavor. Like lambic, the spontaneous fermentation of sikaru wort involved the local microflora like saccharomyces and schizo saccharomyces yeasts. Both lambic and sikaru have been considered high quality premium beers and were used to pay the salaries of farmers, the working class and managers. Today, Gueuze is still known as “Brussels Champaign.”

“There is little doubt that if we could reach for one of the stoneware pots of beer painted by these masters and taste its contents, we would recognize the acidic and fruity flavor of Lambic”
“There is little doubt that if we could reach for one of the stoneware pots of beer painted by these masters and taste its contents, we would recognize the acidic and fruity flavor of Lambic”

The origin of the name lambic remains a source of debate. Some claim that it refers to the alambic, an old name for the mashing vessel that was used to brew lambic, while others point to the latin word lambere (to sip). Lambic may also have been derived from the village of Lembeek in Belgium. Similar mysteries surround the name Gueuze (or Geuze). The importance of lambic in Belgian culture is evident in old paintings (such as Pieter Bruegel the Elder’s “The Wedding”) and literature, culminating in a notorious document of lambic culture in the late 19th century in Belgium called “Les memoires de Jef Lambic.”

Less exalted was the French poet Charles Beaudelaire, who wrote about faro (young lambic with candi sugar) consumption in Brussels: “Faro is drawn from the great latrine, the Senne; it is a beverage extracted from the excrements of the city through its sewer system. This is how the city has been drinking its own urine for centuries.” Beaudelaire even wrote a short poem about it, which goes as follows:

“Do you drink Faro, Mr. Hetzel?
A look of horror crossed his bearded face,
No!, never! Faro! I say this without spleen,
It’s beer that you drink twice.”

Charles Beaudelaire

Beaudelaire would have been pleased with the decline of traditional lambic brewing during the 20th century. At the beginning of the century there were about 130 lambic breweries in the Brussels and the Senne Valley. Today, only a small number of lambic breweries and Geuze blenders survive. If we exclude breweries that mainly offer “modern” and “sweetened” lambics, the number of traditional lambic breweries and blenders is around 10 (as of 2008).  Going forward, there is reason to be optimistic, as evidenced by the creation of organizations to preserve and promote traditional lambic beers, the increased respect that brewers such as Cantillon and Drie Fonteinen receive, and the experiments with wild ales by breweries such as Russian River in the United States. Traditional lambic brewing (and the practice of spontaneous fermentation in general) appears to be making a comeback.

Although some of the information about contemporary lambic brewers, blenders, and cafes in Guinnard’s book is dated (the book was published in 1990), in his review of contemporary lambic brewing the author expresses concern over the fact that artisan lambic brewers have to compete with “lambics” that have been artifically inoculated and carbonated, fermented in steel tanks, pasteurized, filtered, and in the case of fruit lambics, sweetened with syrups and artificial flavors. Since 1998, the European Union decided that only traditional lambic brewers can use the name “oude” (which means old, as in “traditional”) for their products, the situation remains that these modern “lambics” are still being sold under the name lambic, necessitating the need for better education about lambic brewing and grassroots support for breweries and blenders who are committed to the old ways.

After introducing the reader to the history of lambic brewing, the author briefly reviews the sensory properties of lambic beers using a table that includes appearance, aroma, taste and mouthfeel. In reviewing the properties of young and aged unblended lambic, an interesting comparison is made between aged lambic and the vin jaune wines (French for “yellow wine”) of the Château-Chalon area in the French Jura. If there was still any doubt about differences in the physical and chemical properties of lagers and lambic, the  next chapter provides hard data to distinguish them. These data, derived from technical publications on lambic brewing, also highlight the differences between traditional and modern lambics.

The real degree of fermentation (RDF) can range from 63 to 82 percent in geuzes, exceeding the 50 to 68 percent in American lagers. In traditional lambics the attenuation of sugars can be complete, making them  interesting choices for diabetics. As such, calories in lambic beers come from ethanol and residual extract. The “thin” mouthfeel of traditional lambics is explained by the low level of dextrins.  One of the distinguishing characteristics of lambics is of course their acidity and sour taste. Total acidity of lambic beers are reported to be three to eight times as high as American lagers. Measured values for acetic acid and lactic acid in lambics are much higher than in other beers. The vinegarlike aroma of lambics results from acetic acid and ethyl acetate, with the latter disproportionately contributing to the smell because of its lower detection threshold. Although lambics have roughly the same values in bitterness units as American lagers, the use of aged (oxidized) hops and high acidity of the beers imparts little or no bitter taste to the lambic beers. The chapter ends with a fascinating look at  the different HPLC (high performance liquid chromatography) profiles of traditional and modern lambics. As expected, higher residual sugars and dextrins and a lower alcohol content are detected in the modern geuzes and fruit lambics.

The essential ingredients in lambic are malted barley, unmalted wheat, water, hops, and in the case of fruit lambics, whole fruits. Although lambic brewing is considered a highly local phenomenon, it is surprising to learn that the barley and hops often come from other regions such as the UK and central Europe. Although the Schaarbeekse cherries are considered the gold standard for traditional Kriek lambics, local supply is not sufficient to satisfy demand, requiring cherries to be imported from other countries.

Guinnard gives a fairly detailed description of the lambic brewing process which includes a lambic production diagram which seems to describe lambic brewing at the Cantillon brewery. One of the most fascinating features of lambic brewing is the use of a cooling tun or coolship (bac refroidissor) that is used to innoculate the wort. Lambic cooling tuns are very wide and shallow, allowing good exposure of the surface area to the microorganisms that are introduced through the outside air through vented tiles and open louvers. The importance of not disturbing the local microflora is considered so important to traditional lambic brewers that Cantillon decided to keep the old tiles when replacing the roof. It may come somewhat as a surprise to lambic connoisseurs that the old brewing process did not maximize the opportunity for the wort to pick up the local microflora. The author notes that “in the 1850s, the presence of lactic flavor or a ropy appearance (caused by lactic acid bacteria and considered “normal” in today’s lambic fermentations) was regarded as a defect.”

Brettanomyces yeast
Brettanomyces yeast

Without a doubt the most fascinating (and longest) chapter in the book is devoted to the microbiology of lambic fermentation and cellaring. The lambic beers are unique in their reliance on spontaneous fermentation by  the airborne microflora in the area and the brewery. Over the years chemists and food scientists have done important work in documenting the microorganisms that are involved in lambic brewing. Lambics do not only distinguish themselves from lagers and conventional ales in the involvement of “wild” yeasts of the brettanomyces genus but bacteria play a role in their fermentation as well. During the first week the lambic wort is home to enteric bacteria and yeast of the Kloeckera apiculata strain. After two weeks K. apicculata is overgrown by Saccharomyces yeast, converting most of the sugars into alcohol and carbon dioxide. After 3 to 4 months ethanol fermentation levels off to give way to lactic acid bacteria. These lactic acid bacteria contribute to the distinct sour taste of traditional lambics. After eight months yeasts of the Brettanomyces genus dominate. This slow growing yeast is responsible for the distinct “horsey” flavor in lambics.  The Brettanomyces and other oxidative yeasts also contribute to the formation of a film that forms at the surface of the beer. This film protects the aging brew against oxidation and great care is exercised not to break it. The author also reports on the role of spiders in protecting the aging lambic wort from infection; “as predetors of flies, the spiders…are treated with respect and care by most lambic brewers. Killing a spider in their brewery is considered a crime.”

A special case is the microbiology of gueuze. To make a  real gueuze, lambics of different ages (for example, 1, 2 and 3 years) are blended and refermented in the bottle. During bottle fermentation three distinct phases can be distinguished. First, aerobic yeasts such as Candida, Torulopsis, and Pichia proliferate (probably as the result of air exposure during gueuze production), followed by the longest phase during which Pediococcus and Brettanomyces produce its carbonation, and ending with the drop and autolysis of the cells. The author stresses the importance of alternating  warm and cold temperatures (which are traditionally achieved by the changing of the seasons) to satisfy the optimum temperature requirements for the different microorganisms. As can be expected, a live product such gueuze is vulnerable to handling and extreme temperature variations; “In 1931, more than 3 million bottles of gueuze were lost to hot weather in Brussels.”


The book ends with storing and serving recommendations for lambic beers and formulations for how to brew them. Real lambics can only be produced by spontaneous fermentation in areas that have the unique microbial flora for these brews (such as the Payottenland in Belgium). Although attempts can be made to approach the aroma and taste of lambics by using malt, wheat, aged hops and and cultures of the most important yeasts, the author stresses that such beers should NOT be called lambics to avoid confusion and out of respect for those who brew the real thing. Provided these recommendations are taken seriously, the resulting wild ales can  be interesting beers, as evidenced by the creations of brewers like Russian River and Jolly Pumpkin in the United States.

Jean-Xavier’s book on Lambic is a classic and recommended reading for everyone interested in Belgian beers, and lambics in particular.