BJCP 17D
Complex, sour/acidic, pale, wheat-based ale fermented by a variety of Belgian microbiota.
Straight lambics are single-batch, unblended beers. Since they are unblended, the straight lambic is often a true product of the "house character" of a brewery and will be more variable than a gueuze. They are generally served young (6 months) and on tap as cheap, easy-drinking beers without any filling carbonation. Younger versions tend to be one-dimensionally sour since a complex Brett character often takes upwards of a year to develop. An enteric character is often indicative of a lambic that is too young. A noticeable vinegary or cidery character is considered a fault by Belgian brewers. Since the wild yeast and bacteria will ferment ALL sugars, they are bottled only when they have completely fermented. Lambic is served uncarbonated, while gueuze is served effervescent. IBUs are approximate since aged hops are used; Belgians use hops for anti-bacterial properties more than bittering in lambics.
The only bottled version readily available is Cantillon Grand Cru Bruocsella of whatever single batch vintage the brewer deems worthy to bottle. De Cam sometimes bottles their very old (5 years) lambic. In and around Brussels there are specialty cafes that often have draught lambics from traditional brewers or blenders such as Boon, De Cam, Cantillon, Drie Fonteinen, Lindemans, Timmermans and Girardin.
You can view the complete style details on the BJCP website. The 2008 style guide is obsolete but there is a similar 2015 style that you can view below...
OG: 1.040-1.054
FG: 1.001-1.010
IBU: 0-10
SRM: 3.0-7.0
ABV: 5.0-6.5%