Lambic is a brewing style that traces it’s roots back over 400 years, and was probably one of the first “beers” to come out of ancient Mesopotamia. In contrast to the sanitary techniques used by brewers of traditional ales and lagers, which are fermented by carefully cultivated strains of brewer’s yeasts, lambic beer is produced primarily in the Senne valley region of Begium, and utilizes spontaneous fermentation of the wild yeasts and bacteria present in the area. It is this unusual process which gives the beer its distinctive flavour: dry, vinous, and cidery, often with a sour aftertaste.

Like the beers of old, most lambics are brewed from a combination of malted barley and unmalted wheat, the latter often being up to 40% of the mash bill.
Although ancient brewers would simply leave their beers outside in the breeze to spontaneously ferment, now days it is understood that a majority of the yeasts and bacterias used in Lambic production reside within the walls of the breweries. Lambics are also only produced between October and May, limiting the amount of contaminants in the beer.

Another aspect of Lambic brewing that differs from ales and lagers is the way hops are utilized. Hops have been used for centuries as a preservative, bittering agent, and to provide great aromas and flavors to beer. With lambics, the use of hops is almost solely as a preservative. Because lambics are usually aged for several years in port or sherry barrels, dry aged hops, which have lost most of their bitter oils, are added to the beer in quantity to help preserve it, while keeping the hop bitterness to a minimum.

There are several different varieties of Lambics, and many offerings are actually blends of casks brewed in different locations.

Pure Lambic
Unblended lambic is a cloudy, uncarbonated, bracingly sour beverage which is generally around three years old. Very few offerings can be found outside of Belgium.

A mixture of young and old lambics that have been bottled. It keeps well in the bottle and a good gueuze will be given a year to referment in the bottle, but can be kept for 10–20 years. Use of grain adjuncts and inoculation is allowed. Bottle aging is the traditional way to make gueuze, but artificial carbonation is not uncommon. Filtration and pasteurization can occur. Gueuze is golden to light amber in color. Carbonation can be champagne-like. They are sour, acetic and sometimes harsh, usually without bitterness.

Historically, a low-alcohol, sweetened beer made from a blend of lambic and a much lighter, freshly brewed beer to which brown sugar, caramel or molasses was added shortly before serving. Modern faro beer is still characterized by the use of brown sugar and lambic, but is not necessarily a light beer. Modern faro is bottled, sweetened and pasteurized to prevent refermentation in the bottle. Examples are produced by Cantillon, Boon, Lindemans or Mort Subite.

Lambic refermented in the presence of sour cherries and with secondary fermentation in the bottle results in kriek. Traditional versions of kriek are dry and sour, just as traditional geuze.

A Lambic which includes the addition of raspberry (framboise), peach (pêche), blackcurrant (cassis), grape (druif), apple (pomme), banana (banane), pineapple (ananas), apricot (abricotier), plum (prunier), cloudberry (plaquebière), lemon (citron), blueberry (bleuet), or strawberry (aardbei), as either whole fruit or syrup. Fruit lambics are usually bottled with secondary fermentation. Although fruit lambics are among the most famous Belgian fruit beers, the use of names such as kriek, framboise, cassis, etc., does not necessarily imply that the beer is made from lambic. Many of these fruit beers produced in the US are typically artificially sweetened and based on syrups instead of fresh fruit, resulting in a taste experience that is quite remote from the traditional products.

So there you have it, now you know what a Lambic is, now go out and try some. Cheers!