Cafeoutdoors.com: The many varieties of Beer

Google is your friend

http://en.wikipedia.org/wiki/Lambic

a little Hercule Poirot

Brewing
Aged dried hops

Today the beer is generally brewed from a grist containing approximately 60-70% barley malt and 30-40% unmalted wheat. Lambic wort is cooled overnight in the traditional manner: in a shallow, flat metal pan called a koelschip.[2] Here it is left exposed to the open air so microorganisms may "accidentally" inoculate the wort. While this cooling method of open air exposure is a critical feature of the style, the key yeasts and bacteria that perform the fermentation are now understood to reside within the breweries (usually timber) fermenting vessels.[3] Over eighty microorganisms have been identified in lambic beer, the most significant being Saccharomyces cerevisiae, Saccharomyces pastorianus and Brettanomyces bruxellensis. The process is generally only possible between October and May as in the summer months there are too many unfavourable organisms in the air that could spoil the beer.[4]

Since at least the 11th century and probably earlier, hops have been used in beer for their natural preservative qualities as well as for the pleasant bitterness, flavor, and aroma they impart. Today it is the latter that is the reason for their inclusion in almost all beer styles other than lambic. Since the method of inoculation and long fermentation time of lambic beers increases the risk of spoilage, lambic brewers still use large numbers of hops for their antibacterial properties. Traditionally lambic of the early 19th century was a highly hopped beer using 8-9 g/l of locally grown Aalst or Poperinge hops in good condition. [5] Modern lambic brewers however, try to avoid making the beer extremely hop forward and utilise aged, dry hops which have lost much of their bitterness, aroma and flavour [6] Consequently, lambics often have a strong, cheese-like, "old hop" aroma, in contrast to the resiny, herbal, earthy hop bitterness found in other styles. The traditional favourite hop used for Lambic in the nineteenth century was a variety called Coigneau which was cultivated in the Aalst-Asse area in Belgium.

After the fermentation process starts, the lambic is siphoned into old port or sherry barrels (of chestnut or oak) from Portugal or Spain (some of the brewers prefer used wine barrels.) The lambic is left to ferment and mature for one or several years. It forms a velo de flor of yeast that gives some protection from oxidation, in a similar way to vin jaune and sherry; the barrels are not topped up.
Types of lambic and derived beers

Another important feature of lambic is that it is usually a blend of at least two different beers; many "producers" are in fact blenders who buy beers from other brewers, and blend two or more together to create the desired result. A good gueuze, for example, may have occupied space in several different cellars over 6 years or more. While those outside of Belgium are most likely to find the bottled gueuze and fruit versions, there are a wide variety of styles available to the local drinker, and they are often blended again or sweetened with sugar or flavored syrups before drinking, as some examples can be extremely tart.[citation needed]

Most, if not all varieties listed below have Traditional Speciality Guaranteed (TSG) status. (This status does not specify that a product has a link to specific geographical area.)
Lambic (pure)

Unblended lambic is a cloudy, uncarbonated, bracingly sour beverage available on tap in only a few locations. Generally three years old. Bottled offerings from Cantillon and De Cam can be found outside of Belgium.
Gueuze
Main article: Gueuze

A mixture of young (one-year-old) and old (two- and three-year-old) lambics that have been bottled. It undergoes secondary fermentation, producing carbon dioxide, because the young lambics are not yet fully fermented. It keeps in the bottle; a good gueuze will be given a year to referment in the bottle, but can be kept for 10–20 years. Gose, a German top-fermenting style, is not to be confused with gueuze.
Mars

Mars traditionally referred to a weaker beer made from the second runnings of a lambic brewing. It is no longer commercially produced. In the 1990s, the Boon brewery made a modern Mars beer called Lembeek's 2% (the 2% referring to the alcohol content), but its production has since been discontinued.
Faro

Historically, a low-alcohol, sweetened beer made from a blend of lambic and a much lighter, freshly brewed beer (called meertsbier, not necessarily a lambic) to which brown sugar (or sometimes caramel or molasses) was added.[7] Sometimes herbs were added as well. The use of the lighter beer (or even water) and of substandard lambic in the blend made this a cheap, light, sweet beer for everyday use. The 19th century French poet Charles Baudelaire commented on Faro's (to him) disagreeable aftertaste, "It's beer that you drink twice", believing that the Faro in Brussels was brewed from the waters of a river (the Senne or Zenne) that was also used as a sewer.[8]

The sugar was originally added shortly before serving, and therefore did not add carbonation or alcohol to the beverage (because the sugar did not have the time to ferment). Modern faro beer is still characterized by the use of brown sugar and lambic, but is not necessarily a light beer. The use of meertsbier has disappeared, and modern faro is not viewed as cheap or light. Modern faro is bottled, sweetened and pasteurized to prevent refermentation in the bottle. Examples are produced by Cantillon, Boon, Lindemans or Mort Subite.
Kriek
Main article: Kriek lambic

Lambic refermented in the presence of sour cherries (morello cherry) and with secondary fermentation in the bottle results in kriek.[1] Traditional versions of kriek are dry and sour, just as traditional Gueuze.
Fruit

Lambic with the addition of raspberry (framboise), peach (pêche), blackcurrant (cassis), grape (druif), or strawberry (aardbei), as either whole fruit or syrup. Other, rarer fruit lambic flavorings include apple (pomme), banana (banane), pineapple (ananas), apricot (abricotier), plum (prunier), cloudberry (plaquebière), lemon (citron), and blueberry (bleuet). 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 or frambozen, cassis, etc. does not necessarily imply that the beer is made from lambic. The fruit beers produced by the Liefmans brewery, for example, actually use a brown ale (Oud Bruin), rather than a lambic as a base. Many of the non-traditional fruit beers derived from lambic that were commercialized in the last decades are considered to be low quality products by many beer enthusiasts.[1] These products 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.