Return of a Classic Sour Ale

Traditional lambic, gueuze, and fruited lambic may be “Love ‘em or hate ‘em” beer styles, but in the recent past, more homebrewers have ventured into making these classic sour ales. Once rarely attempted by homebrewers, these beer styles have been drawing the adventurous to brew clone versions of world-class examples. Names such as “Cantillon” and “Lindemanns” are commonly heard, and small-batch clone recipes for these classic sour ales are finding their way into the homebrewer’s portfolio. In the following text, I will use the word “lambic” to include gueuze (a blend of young and aged lambics) and fruited lambics (i.e. kriek, framboise, etc.).

There are many sours currently being produced in North America by commercial breweries on both coasts and in between that are quite good. By no means am I insinuating in this article that they are inferior, but I believe to understand where these beer styles came from we must go back to the Old World and see where sour ales originated. So for this article I will specifically focus on Belgian lambic brewers, blenders, recipes, brewing techniques, and their interesting history. The following text will give the hombrewer some necessary facts to understand lambic brewing, its roots, and the complex parameters incorporated in its variations of gueuze and fruited lambics.

I will refer primarily to the Brewers Publications, Classic Beer Style Series Lambic by Jean-Xavier Guinard. This is a “must have” reference for those who wish to learn, understand, and cherish this very distinctive Belgian ale. It has been out of print for many years, with copies often selling for above $100, but luckily it was re-released on Kindle.

Style Parameters of Lambic

A brief review of the Beer Judge Certification Program (BJCP) Style Guidelines for straight unblended lambic will help the brewer understand some flavor and aroma characteristics one should expect in this complex ale. According to the guidelines, the aroma typically has sour, earthy, barnyard, goaty, and horse blanket characters. The appearance of the beer is typically hazy with color in various shades of golden. Flavors and aromas typically change with age. Young versions are quite sour and acidic, with aged examples mellowing with complex notes of Brettanomyces, lactic and acetic acids, and fruity esters.

Commercial lambic breweries such as Cantillon tend to develop a “house character” from their blend of fermentation agents and brewing techniques. As one walks through this Brussels landmark brewery, the ambient aromas in the air are very similar to those in their beers. When home and enjoying a Cantillon, the fragrance brings me back to the little brewery in the Brussels neighborhood of Anderlecht.

As I traveled throughout the Senne Valley area (lambic country) in Brussels and around the outskirts of the city a few years ago, I visited many lambic breweries. In the vicinity of each are small neighborhood cafes serving local lambic made right up the road. Usually the person pouring would be the cafe owner or someone in the immediate family who is on a first name friendship with the lambic maker. One memorable small lambic pub that brings pleasant memories to me is the In De Oude Smis Van Mekingen cafe in the small village of Sint-Pieters-Leeuw, near Brussels. The person pouring my lambic was a co-owner and a personal friend of Frank Boon, the brewer who made the Moriau Oude Geuze I sipped on and enjoyed while chatting with the pourer. The brewery was right up the road.

As we toured a loop around Brussels, Belgium called the Pajottenland, we visited many small lambic breweries and small cafes in the land I like to call “lambic country.” Each of the sour beers I enjoyed was distinctive, with “terroir” and characteristics that made each stand out as representative of the individual lambic brewery and their master brewer.

HORAL and The Lambic Brewers and Blenders of Belgium

There are currently eleven commercial breweries in Belgium producing lambic. They are: Cantillon, Belle-Vue, Boon, De Keersmaeker (Mort Subite), De Troch, Girardin, Lindemans, Oud Beersel, Timmermans, Van Honsebrouck (St. Louis), and 3 Fonteinen.

There are also three others that don’t brew, but instead buy freshly produced wort from several of the lambic breweries and then ferment/age, blend, and bottle it in their own facility. The three active lambic blenders are: Tilquin, De Cam, and Hanssens Artisanaal.

Many of these brewers and blenders are also part of a consortium that was formed in 1997 by Armand Debelder, the Brewer and Owner of 3 Fonteinen brewery located in Beersel. This collective group is called HORAL, an acronym for Hoge Raad voor Ambachtelijke Lambiekbieren. This translates to “High council for artisanal lambic beers.” It is a group of like-minded lambic brewers and blenders who work together to promote lambic beer and the very rare culture that surrounds it. Quoting the goal of HORAL, “In the face of continued decline, we wish to promote and protect traditional lambic beers.” Interestingly, Cantillon is not a member.

I personally have seen this organization’s success. In the past few years, the interest and resulting growth of Belgian lambics has soared beyond expectations. This has also affected the exponential growth of American brewers who are producing lambic-style beers. I spent some time in Italy a couple years ago, and saw a similar interest there in producing spontaneous ales.

Lambic Brewing Basics Explained

Spontaneous fermentation has been well-documented over the years. It’s been said that lambic brewing is the oldest method of making beer still in use. Belgian brewing expert and beer historian Marcel Gocar describes similarities of beer produced 5,000 years ago in Mesopotamia by the Sumerians and the typical lambic brewing process still in use today. If one were to research the history of another Belgian beer style — saison — they would find similarities in their sour, rustic, and earthy flavors. The understanding of bacterial and yeast fermentation was not clearly understood until the late 1800s with the important research and discoveries by the esteemed microbiologist Louis Pasteur.

I’ll quote directly from Guinard’s book with his perfect explanation describing spontaneous lambic fermentation. The following is from a lambic-loving companion who bought Mr. Guinard his first lambic in a Paris pub and introduced him to this style of beer. I cannot describe the brewing process any better, and wish I were there in that pub when it was explained. It goes like this;

“Lambic is the only beer of its kind in the world. It is made by spontaneous fermentation of a wort produced from 40 percent unmalted wheat and 60 percent malted barley malt. Mashing follows a temperature profile. The temperatures are increased by one or two decoctions of portions of the mash, and by additions of boiling water. The wort is boiled for at least three hours with aged hops that have lost their bittering power but have retained their antiseptic properties. Lambic is brewed mostly within ten miles of the city of Brussels, because the proper microbial flora is found only in that limited area. Production is concentrated in the western districts of Brussels, spreading out into the nearby farming villages collectively known as the Payottenland. Traditionally, lambic is brewed only from October 15 to May 15 because high summer temperatures can spoil the fermentations. The inoculation of the wort with the local microbial flora is achieved by letting the hot wort cool overnight in a wide and shallow cooling tun, which leaves a large wort surface area in contact with the atmosphere. The next morning, the wort is pumped into wooden casks in which it picks up some additional microorganisms among those lodged in the wood from previous use. The fermentation involves a sequence of yeasts and bacteria, the combined action of which over a period of several months is a lambic that is fruity, acetic, and sour but not bitter.”

Perfect explanation!

Brewing the Beer

My brewing technique and recipe are similar to Guinard’s. I’ve performed decoction and straight infusion mashes using both malted and unmalted wheat (using only un-malted wheat is one of the requirements to brew a true lambic, but I’ve found malted wheat works fine). Unfortunately, I don’t have a coolship in the neighborhood of Brussels’ local microbial flora, but instead I use a 5-gallon (19-L) oak barrel that I’ve inoculated with various lambic bacteria and yeast over the years. Occasionally, I’ll pour the dredges of a favored lambic into my barrel to add some additional complexity. Though there are many recipe variations used by different brewers to produce lambic, these are always fermentation-driven ales. The percentage of wheat (30–40%), the type of pale malt, and the brewing technique are very important, but this style is really all about the microbial aspect of the fermentation and its byproducts. Lambic fermentation depends on a very specific and complex fermentation regime. This is a slow process of fermenting that takes months or years to complete. It helps to have the patience of a saint.

Lambic brewing, though its process is similar to brewing other beer styles, does have its own idiosyncrasies. My research about classic lambic brewing techniques describes many variations of mashing procedures and ingredient use.

Belgian lambic brewers typically incorporate unmalted wheat into the grain bill, warranting an additional step called the cereal mash process. Decoction mashing may suffice, but I like to follow Guinard’s suggestion of the alternative method of adding unmalted wheat flakes directly to the mash. The starch in wheat flakes is already gelatinized (making it more soluble), so conversion by the enzymes utilizing a typical infusion mash temperature of 153–158 °F (68–70 °C) is effective.

For grain/water (grist) ratio, I use the rate of one pound (0.45 kg) of crushed grain per quart/liter of water. In the case of the example recipe on at the end of this story, I combine 10 quarts (9.5 L) of 168 °F (75 °C) water with 10 lbs. (4.5 kg) of the crushed wheat and barley to mash at 155 °F (68 °C). After mashing for an hour I sparge (rinse) with 168 °F (75 °C) water until I collect 6 gallons (23 L), which subsequently will be boiled down to 5.25 gallons
(20 L).

This recipe calls only for 1 oz. (28 g) of hops added at the start of the 60-minute boil. The hops used to brew lambics are typically aged warm for one to three years, which causes oxidation to occur and leads to the loss of bitterness from the alpha acids. The hops do, however, retain their preservative qualities.

Yeast and Bacteria; The Defining Factors in Brewing Classic Lambics.

One factor I have found to improve my lambics is pitching sequential additions of specific yeast strains and bacteria over a long period of time. Using the evolutionary graph designed by Van Oevelen, found in Guinard’s Lambic book, a brewer can see when peak activity occurs with particular yeasts and bacteria over a 24-month timeframe. You can refer to this book to find the chart and read more about his recommended sequential additions. My interpretation of the fermentation process has encouraged me to initially pitch a starter yeast blend that contains Saccharomyces cerevisiae and other typical lambic strains of yeast and bacteria (Lactobacillus, Pediococcus, and various Brettanomyces strains). Commercial yeast companies offer these blends, making it easy to pitch. My favorites are Wyeast 3278 (Belgian Lambic Blend) or White Labs WLP655 (Belgian Sour Mix 1), both of which offer the brewer the yeast/bacteria blends necessary to create a great lambic. If you choose, single packs of various Brettanomyces, Pediococcus, and Lactobacillus strains are also available and you can come up with the mix on your own.

Referring to the Van Oevelen’s evolutionary graph, after my initial pitch of a yeast/bacteria blend on brew day, I’ve chosen to pitch separate strains of Lactobacillus and Pediococcus directly into the fermenter at three months from the initial brewing date. I then allow the fermentation to continue. At eight months, I pitch separate starters of Brettanomyces bruxellensis, and Brettanomyces claussenii. I don’t perform a secondary transfer, but continue my fermentation in the original vessel. Though the homebrewer may do the entire fermentation in a glass carboy, I conduct mine in a 5-gallon (19-L) oak barrel. As fermentation continues, complex reactions take place causing acid production and development of various by-products.

My last batch of lambic was fermented for 8 years in an old Buffalo Trace Bourbon barrel. Though I don’t think that much time was necessary, it was a barrel aging process I’ve always wanted to try. As fermentation progressed, I tasted and documented the evolving flavors of the beer monthly to see how they had changed and learned how this style of beer develops. An important note for homebrewers considering extended barrel aging is the importance of topping off the barrel. This can either be done with another lambic (preferred, and a great way to make gueuze) or with a neutral beer (I used a light American lager). The beer added will fill the air space caused by evaporation through the barrel staves. This evaporative loss is lovingly called the “angel’s share.” The brewer must perform this important step every few weeks as to not develop elevated levels of acetic acid (vinegar). The alcohol produced during fermentation may be chemically converted to vinegar by the presence of acetobacter bacteria and oxygen (air is 22% oxygen) in the space left by evaporation.

Lambic fermentation is a long and slow process that utilizes many complex “controlled spoilage-type components” that brewers usually dread. But in this case, these by-products make the lambic what it is; a complex sour ale with wine-like and estery characteristics. Complex notes of acetic acid (vinegar), lactic acid, and Brettanomyces develop over time. Saccharomyces sp. does not ferment the longer chain starches present in unmalted wheat, but over time the presence of Brett strains and Lactobacillus will do so, producing additional complex textures and flavors in the beer. Research has shown that hundreds of complex reactions occur during this long-term fermentation. The brewer’s technique, choice of ingredients, and especially the fermentation agents incorporated, will produce a lambic with his or her own signature.

Experience, patience, and an adventurous soul will reward the brewer with the complexities of a lambic they would be proud to put their
name on.

Zoc’s Traditional Lambic

(5 gallons/19 L, all-grain)
OG = 1.045   FG = 1.008}
IBU = 10   SRM = 3   ABV = 4.8%

6 lbs. (2.7 kg) pale malt
2 lbs. (0.9 kg) malted wheat.
2 lbs. (0.9 kg) unmalted wheat
1 oz. (28 g) aged Styrian Goldings hops (60 min.)
Wyeast 3278 (Belgian Lambic Blend) or White Labs WLP 655 (Belgian Sour Mix 1) yeast
Wyeast 3335 (Lactobacillus buchneri) or White Labs WLP673 (Lactobacillus buchneri)|
Wyeast 5733 (Pediococcus damnosus) or White Labs WLP (Pediococcus damnosus)
Wyeast 5112 (Brettanomyces bruxellensis) or White Labs WLP650 (Brettanomyces bruxellensis)
Wyeast 5151 (Brettanomyces claussenii) or White Labs WLP645 (Brettanomyces claussenii)
3⁄4 cup corn sugar (if priming)

Step by Step
Combine 2.5 gallons (9.5 L) of 168 °F (75°C) water with the crushed wheat and barley. Mix well and adjust the temperature of the mash to 153 °F (68 °C). Let the mash rest at 153 °F (68 °C) for one hour and then recirculate until the wort runs clear. Sparge with 168 °F (75 °C) water until you get 6.25 gallons (24 L) into the boil kettle, which will be boiled down to 5.25 gallons (20 L).

Add hops when the wort comes to a boil and boil for 60 minutes. After the boil is complete, proceed to chill the wort to below 80 °F (15 °C), and transfer the contents into your fermenter. I ferment my lambics in a 5-gallon (19-L) oak barrel, but if you do not have a barrel then feel free to use your traditional fermenter. Pitch your yeast and bacterial blend (which contain strains of Saccharomyces and Brettanomyces yeasts and the bacterial strains of Lactobacillus, and Pediococcus) and aerate wort.

Aging times can vary but allow it to remain in the fermenter at least a year. After my initial pitch of a yeast/bacteria blend on brew day, I pitch the Lactobacillus and Pediococcus bacteria into the fermenter at three months from the initial brewing date. I then allow the fermentation to continue. At eight months, I pitch separate starters of Brettanomyces bruxellensis, and Brettanomyces claussenii. I don’t perform a secondary transfer, but continue my fermentation in the original vessel.

After a year I like to pull monthly samples to taste how the beer is evolving. Bottle or keg when the taste is what you were shooting for. Bottles can be kept for years and flavors will continue to evolve as they are cellared.

Zoc’s Traditional Lambic

(5 gallons/19 L, partial mash)
OG = 1.045   FG = 1.008
IBU = 10   SRM = 4   ABV = 4.8%

4 lbs. (1.8 kg) golden light liquid malt    extract
2 lbs. (0.9 kg) malted wheat.
2 lbs. (0.9 kg) unmalted wheat
1 oz. (28 g) aged Styrian Goldings hops (60 min.)
Wyeast 3278 (Belgian Lambic Blend) or White Labs WLP 655 (Belgian Sour Mix 1) yeast
Wyeast 3335 (Lactobacillus buchneri) or White Labs WLP673 (Lactobacillus buchneri)|
Wyeast 5733 (Pediococcus damnosus) or White Labs WLP (Pediococcus damnosus)
Wyeast 5112 (Brettanomyces bruxellensis) or White Labs WLP650 (Brettanomyces bruxellensis)
Wyeast 5151 (Brettanomyces claussenii) or White Labs WLP645 (Brettanomyces claussenii)
3⁄4 cup corn sugar (if priming)

Step by Step

Place crushed wheat in a large grain bag. Heat 1.5 gallons (5.7 L) of water to 168 °F (75 °C) and submerge the grain in the water. Try to mix the grain so no dry pockets exist. Let the mash mixture rest at 153 °F (68 °C) for one hour. When the mash is complete, place the grain bag in a large colander and wash with 1.5 gallons (5.7 L) of hot water. Stir in the liquid malt extract and top off the kettle with water to get 6.25 gallons (24 L) of wort into the boil kettle. Follow the remainder of the all-grain recipe.

Issue: September 2018