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Traditional lambic makers brew during the cooler months of the year, and take the hot summer off. Spring is a great time for homebrewers to begin a sour beer. The main fermentation can complete at normal ale temperatures, and then the beer can sour over the summer. During this time, the temperature of the fermenter can rise (within reason). The added heat will help the souring bacteria do their work more quickly.

One type of traditional lambic is gueuze — a blend of young and old lambics. “Young,” in this case, means one year old and “old” means either 2 or 3 years old. Today I’ll lay out a plan for a homebrewer to brew lambic-style ales for three years, then blend a gueuze from 1, 2 and 3 year old lambic in the fourth year. If you’re wondering who would ever do such a thing, I know one homebrewer who did it — me. (And, my resulting gueuze won Best of Show at the Austin ZEALOTS Inquisition that year.)

Incidentally, some homebrewers use the term p-lambic (or pseudo-lambic) for homebrewed lambics. This is partially out of deference to Belgian brewmasters. In addition, some say you cannot brew a “true” lambic unless you live in the Senne valley of Belgium, because your native microflora is different. So, they invented the term “p-lambic” to differentiate between the two.

I think “p-lambic” is a clunky term and I’ll use the words “lambic-style ale” or “lambic” to describe these beers. I think context will make it clear whether I’m referring to a traditional lambic (brewed using traditional methods around Brussels, Belgium) or a homebrewed sour ale inspired by traditional lambic. In a like manner, I respect British brewmasters, and I don’t live in Burton on Trent — and hence don’t have access to their water. But if I want to brew a British IPA, I can add gypsum to my water and I would call it an IPA, not a pIPA.

Sour Myths

Some homebrewers are reluctant to brew a sour beer, fearing their home brewery will become contaminated and all their subsequent beers will sour over time. In addition some have been led to believe that making a sour beer requires the use of exotic techniques or unusual and expensive equipment. Neither of these things is true.

Hard surfaces, such as glass and stainless steel, can be satisfactorily cleaned and sanitized using normal methods. Soft parts, such as tubing and stoppers, can be dedicated to brewing sour beers, reducing the risk of cross-contamination. (For more on this, see my article on sour beers and sanitation.) If you can brew a German hefe-weizen and not have all your subsequent beers be hefe-weizens, you can brew a sour beer and not have all your subsequent beers turn sour.

Traditional lambics are brewed using several methods not seen in the production of other beers. Traditional lambic brewing begins with a turbid mash, a long step mash that starts thick and ends up very thin. The grist is barley malt and raw (unmalted) wheat — usually soft, white wheat. The beer is sparged with very hot water (around 190 °F/~90 °C) and a large amount of wort is collected. This requires a long boil, three or more hours, to condense. Aged hops are used in the kettle. After the boil, the wort is pumped to a wide, shallow vessel called a coolship. The beer cools in this vessel overnight and is also inoculated with the local microflora, including the bacteria that will sour the beer. The beer is then pumped to barrels, where it is further inoculated with souring bacteria. The beer ferments and is then aged, with oxygen slowly penetrating the barrel over time. A tiny amount of exposure to oxygen is a good thing in the sour beer fermentation.

You can attempt to brew a lambic using traditional methods if you’d like. However you can also use modern homebrewing methods, and your normal homebrewing equipment, to make a wonderful sour beer. And if you make a few adjustments to get the right character in the beer, you can also make a very credible homebrewed lambic-style beer.

Recipe and Procedures

In the next article, I’ll give a recipe for a homebrewed lambic. I will include detailed instructions, and explain the rationale behind every step. In this article, I’ll lay out the plan that will put you in position to blend a lambic four years from now. The basic idea is to brew two buckets of lambic each year, turning one into a fruit beer the following year and saving the other one for the gueuze. You could brew one bucket of lambic a year, and save each one until year four, but then it would be four years before you got to taste your first sour creation. In your first year, you’ll need two bucket fermenters. In the coming years, you’ll need to buy one new bucket each year.

The Four-Year Plan

In the first year, make 10 gallons (38 L) of wort and split that between two 5-gallon (19-L) bucket fermenters. If you don’t have aged hops, use fresh hops. But, purchase the hops for your batches in second and third years (and perhaps beyond). Age these hops for your later brews. Ferment the beer with one of the commercially available lambic or sour beer blends of yeast and bacteria. Set your fermenters out-of-the-way — but not so out-of-the-way that you forget about them. You should check on them every month or so to see that there is still water in the airlock.

In the spring of the second year, rack one of the beers to a glass carboy. (Or, leave it in the bucket if you have two bucket fermenters on hand.) Save this until fruit is in season and make a kriek (cherry lambic) or framboise (raspberry lambic). I’ll give the instructions for making a fruit lambic with the recipe in the next article, along with the recipe for the base beer. Make 10 more gallons of wort (38 L) and split that between two 5-gallon (19-L) buckets. For this wort, you will have hops that have aged at least one year. You will now have three buckets, two that you just brewed and one from the previous year — and of course you’ll have the carboy of sour beer waiting for fruit.

In the spring of the third year, set aside another bucket to make a second fruit beer. This will leave you with one bucket of 1-year-old lambic and one bucket of 2-year-old lambic. Brew 10 more gallons (38 L) of wort — with hops that have aged two years — and split that between two buckets. Next year, you will blend three beers together to make your gueuze.

In the fourth year, you’ll split off another bucket to make another kriek or framboise. And, it’s (finally) time to blend the gueuze. You can keep the ball rolling by brewing two more buckets of lambic (with three year old aged hops). With these beers, you’ll be able to blend another gueuze in year seven if you keep brewing two buckets of lambic a year. (To keep the ball rolling and have a gueuze to blend each year beyond year four, you would need to brew three buckets of lambic each year — four if you wanted to additionally have a fruit lambic each year.)

Blending

Blending is a topic unto itself and I will devote an entire article to it. Once your gueuze is blended, it will likely require another year in the bottle to carbonate and condition. In other words, it will take approximately five years from your brew day before you taste your creation. By this time, however, you will have become an accomplished sour beer brewer. You will have enjoyed several fruit lambics. And you will have a delicious beer — with a great story behind it — to savor with family and friends.