Ons unieke proces

Gueuze is blended, Lambic is brewed

Gueuze is blended, not brewed. Gueuze is created by combining several Lambic beers. Those Lambic beers, however, are brewed. Still with me? We are happy to show you all about the art of making Gueuze beer.


Lambic is brewed with malt and wheat, but they are about the only things it has in common with other beers. Unlike other brewers, Lambic brewers do not add yeast to their brew. Lambic is made with a process referred to as spontaneous fermentation. All that is needed is the ambient air of the Zenne valley to work its magic on cold winter nights. This activates naturally occurring wild yeasts and bacteria in the brew, which is in an open cooling vessel. This produces a different, organic result every time.


Lambic we make in the winter months is given ample time to mature in large oak barrels: our foeders. This allows the beer to continue to evolve thanks to the rich microculture living in these old oak barrels. Gueuze is made by blending Lambic beers from different years – and therefore different foeders. Oude Geuze Boon for example, is a blend of Lambics that matured for 1, 2 and 3 years. That blend then undergoes several months of bottle conditioning, a second fermentation inside the bottle.

Spontaneous fermentation with well-considered processes

Oude Geuze Boon may well be our flagship product, but we offer a wide range of characterful beers. They owe their unique taste to various specific actions in the process. For example, our VAT Monoblends are mainly made with old Lambic from the same barrel, while our Black Labels are based on Lambic beers with the highest level of fermentation. We make our Oude Kriek and Framboise by adding fresh fruit to ferment together with young Lambic. We then use the resulting 'cherry Lambic' to create various beers with the expression of real fresh fruit.

Foeders with character

The Lambic beers that we use to make our Gueuze also owe their character to the foeders they mature in. The Boon Brewery currently has 161 foeders and each one of these oak barrels has a long history. On average, they undergo a thorough overhaul every 15 years. We do this in our coopers’ workshop under the watchful eye of our chief cooper Frank Boon. The workshop is unique in Belgium: it is the only place in the entire country where you will find that much expertise and craftsmanship with regard to barrels.

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