Styles  /  Sour & Wild Ale  /  Flanders Oud Bruin

Flanders Oud Bruin

The East Flanders sour brown ale — malty, deep brown, gently sour, with soft dried-fruit character from long aging and mixed-culture fermentation.

Also known as Belgian-Style Flanders Oud Bruin or Oud Red Ales, Flanders Brown Ale, Old Brown, Oud Bruin

The East Flanders sour brown ale — malty, deep brown, gently sour, with soft dried-fruit character from long aging and mixed-culture fermentation. Typically 4.0–8.0% ABV, deep brown to mahogany. Compared to its cousin Flanders Red, Oud Bruin is maltier, rounder, and less overtly acetic — the sourness plays a supporting role to dark-malt sweetness rather than defining the profile.

In the glass

Appearance
Deep brown to mahogany, clear to slightly hazy, with a moderate off-white to tan head that may fade quickly in more acidic examples.
Aroma
Rich malt — caramel, toffee, light cocoa, raisin, fig, dark cherry — with moderate lactic sourness and light acetic notes. Oxidative sherry-like character is traditional in aged examples. No hop aroma expected.
Flavor
Deep malt sweetness — caramel, toffee, raisin, plum, dark cherry — balanced by moderate lactic sourness. The acidity should complement rather than dominate. Hop bitterness is low. Finish is medium-dry to medium-sweet depending on blend, with lingering dark fruit and gentle tartness. Traditional Oud Bruin is a blend of young and aged beer, the aged portion contributing most of the sourness and complexity.
Mouthfeel
Medium body, moderate carbonation, smooth. Acidity gives a mild astringent lift on the finish.

Origin

Oud Bruin (“old brown”) developed in East Flanders, centered on the city of Oudenaarde, as a local tradition of aging dark ale for a year or more so that wild yeasts and bacteria could lend it cherry, plum, and raisin character with a gently acidic finish. The aged beer is then blended with younger, sweeter beer to soften the tartness and round out the malt. Oudenaarde’s Liefmans, whose oldest written reference dates to 1679, is the defining producer; its premium aged blend Goudenband (“Gold Band,” named for the band once tied around the bottle and adopted around 1957) is the reference example. The original Liefmans family held the brewery until 1974, after which it changed hands repeatedly; brewing on the historic Oudenaarde site ended in 1991, and after a 2008 bankruptcy the brand was acquired by Duvel Moortgat, which today brews the wort at its Breendonk plant and ships it to Oudenaarde for fermentation, aging, blending, and bottling. The name “old brown” itself reflects the practice, born of necessity in an era before refrigeration, of reviving an over-aged sour beer by blending it with fresh young beer rather than discarding it.

Notes

Flanders red, the West Flanders style anchored by Rodenbach, is a close cousin — the red is more acetic and wine-like, while oud bruin is maltier, rounder, and leans toward dried fruit. Belgians often treat the two as one style and may be confused by the English-language split. A separate trap is the Dutch “oud bruin,” an entirely different drink: a low-alcohol, artificially sweetened brown lager with no relation to the sour Flemish ale beyond the shared name. Among Liefmans’ own range, the entry-level Oud Bruin bottling is a lighter, sweeter, pasteurized beer, while Goudenband is the traditional blended, cellar-aged version.

Defining examples

Liefmans Goudenband·Liefmans Oud Bruin·Petrus Oud Bruin·Ichtegem’s Oud Bruin·Monk’s Cafe Flemish Sour Ale

Sources
BA 2026Belgian-Style Flanders Oud Bruin or Oud Red Ale
BJCP 2021 · 23COud Bruin
NABA 2024Flanders Oud Bruin
Liefmans. “Brewery.” Accessed June 13, 2026.
Wikipedia contributors. “Liefmans Brewery.” Wikipedia, The Free Encyclopedia. Accessed June 13, 2026.
Oliver, Garrett. The Oxford Companion to Beer. New York: Oxford University Press, 2012.