Lambic & Gueuze

Lambic is by itself a sour, dry beer. After one to three years of spontaneous fermentation and maturation on wooden barrels, almost all sugars are fermented.

Traditional fruit lambic, such as kriek, is also dry and sour. The fruit usually goes into the barrels halfway through maturation, so that yeasts and bacteria can ferment the fruit sugars too. Fermented fruit tastes different from fresh fruit, and the fruit flavour fades over the years.

The BJCP and the Brewers Association both describe that there are modern versions that are sweetened after fermentation, with sugar or sweetener. Sweetening is not new, by the way: faro is sweetened lambic, and according to beer historian Roel Mulder, faro was usually already sweetened at the end of the 19th century; sweetening with sugar is already described in 1864.

If you are looking for the traditional, dry version, look for the word 'oude'. Oude geuze and oude kriek are protected in the EU and must, among other things, referment in the bottle.

It is right that lambic traditionally comes from the Senne Valley and the Pajottenland, in and around Brussels. The EU product specification speaks of fermentation under the influence of micro-organisms from the air.

But researchers cautiously write that this contamination from the air during cooling is 'assumed'. In addition, microbes get into the beer via the brewery equipment and especially via the inside of the wooden barrels; they sit up to 1.2 cm deep in the wood. In American 'coolship ales', which are made in the same way, a comparable succession of microbes has been found.

Legally, too, lambic is not a regional product. The European protection, a Traditional Speciality Guaranteed, protects the method and is not tied to an area. Roel Mulder also names two West Flemish breweries that make lambic (as of 2018), and in the 19th century lambic was even brewed in the Netherlands.

In short: real lambic traditionally comes from the region around Brussels, but 'only there can it be done, thanks to the air' is a simplification.

The story of a centuries-old, medieval lambic goes back largely, according to beer historian Roel Mulder, to an article from 1970 by the Halle town guide Marcel Franssens, which later appeared as a booklet.

According to Mulder, in Brussels sources faro first turns up in 1721 and lambic only in 1794, as 'allambique'. The often-cited 'recipe' from 1559 is a regulation for the brewers of Halle. It only describes which grain went into it, with much more wheat than in lambic and also oats, and calls the beers 'keutte' and 'houppe' (kuit and hoppenbier). It is therefore not about lambic.

Spontaneous fermentation and years of barrel maturation are not demonstrated before the 18th century. If lambic only arose in the 18th century, the jugs in Bruegel's 16th-century paintings cannot contain lambic.

Since the European protection of 1997, lambic beers made by the traditional method may put 'oude' on the label. According to beer historian Roel Mulder, 'oud' therefore refers not to the age of the beer, but to the way of making it. Still, the word is not entirely unrelated to age.

The protected names are Oude Geuze, Oude Geuze-Lambiek, Oude Lambiek, Oude Kriek, Oude Kriekenlambiek, Oude Frambozenlambiek and Oude Fruit-lambiek, with French forms such as Vieille Gueuze, Vieux Lambic and Vieille Kriek. They are a Traditional Speciality Guaranteed (TSG), and since 2017 the name itself has been reserved.

The EU product specification does set age requirements. For oude geuze, the weighted average age of the lambics is at least one year, and the oldest lambic has matured for at least three years on wood. For oude kriek, the oldest lambic must have lain on wood for at least one year, and the fruit must be equal to 10–25% of the weight of the end product. In addition, refermentation in the bottle and a number of chemical limit values are mandatory, such as a pH of at most 3.8.

The protection of the ordinary names, such as lambiek, geuze, kriek and faro, expired on 4 January 2023, according to the EU register eAmbrosia. And according to Mulder, in 2018 not every traditional producer put the word 'oude' on the label.