The lambic in Foeder 31 that was used for this Oude Geuze Boon VAT issue matured for four and a half years. Foeder 31 is a large oak barrel that was built between 1905 and 1908 by the Bodenheim company in Kassel (Germany). The barrel ended up in a Brussels lambic brewery in 1919 as part of a large batch of material that was sent to Belgium as compensation for the damage suffered by Belgium during the First World War. The cask served in this brewery until 1988, when it was sold together with 20 other foeders to the Boon brewery.
Initially, these casks were used to ripen 1-year lambic for Oude Geuze Boon. The casks that produced the finest lambic, including Foeder 31, were reserved from 1992 for the production of Geuze Mariage Parfait. In 2008 the barrel was due for a major overhaul. Cracks were found on the underside. The cask was partly dismantled in the coopers workshop. Twelve staves (the wooden beams that make up the barrel) were replaced by new ones.
On November 30, 2015, Foeder 31 was filled with lambic from Boon’s new brewing hall for the first time. The extra aromas added by the new oak and the now 100-year-old microflora in the wall of the barrel gave a particularly fine lambic after 3 years of maturation. Frank Boon therefore decided to allow this lambic to mature further. Frank and his sons only bottled the lambic after 4 and a half years in the barrel. Never before have they allowed lambic for VAT production in the cask to age more than 3 years. The results are impressive. VAT 31, brewed on November 30, 2015 and bottled on May 14, 2020, has become a delicate, fine Oude Geuze with a fine sparkle and a pleasant cognac-like nose. The velvety yet firm aroma with notes of apricot and nuts is underpinned by a clear oak character.