Flanders Brown Ale

A malt-forward, brown Belgian sour ale with caramel, dark fruit, mild acidity, and soft oxidative tones. Smooth and rounded. Compared with Flanders Red Ale, it is less sharply acidic and more centered on darker malt richness.

Defined by the balance between aged acidity and malt sweetness, creating a mellow sour profile.

Also known as: Our Bruin; Flemish Brown Ale; Belgian Brown Sour
Family: Sour & Funky Beers - Sour, tart, wild, or mixed-fermentation beers
Variant of Sour Ale - Within the Expressive Ales, defined by a clearly dominant sensory driver such as hop intensity, yeast expression, strength, or acidity.
Variant influence: Malt-forward sour ale with softer acidity, caramelized malt depth, and oxidative notes from extended wood aging.
Explore in Explorer →

ABV, IBU and colour

This section summarises the typical alcohol strength, bitterness level and colour range of Flanders Brown Ale within the GBI model.

ABV: 5,7%
IBU: 15
Colour: 20,5 SRM / 40,4 EBC

Taste profile

The sensory profile below shows the typical intensity range of the 15 core flavour dimensions.

Colour:
Deep amber Brown
Clarity:
Clear Slight haze
Aroma – Malt:
Medium High
Aroma – Hop:
Low Medium
Aroma – Yeast:
Medium High
Aroma – Special:
None Low
Sweetness:
Medium High
Sourness:
Low Medium
Bitterness:
Low Medium
Body:
Low Medium
Astringency:
Low High
Carbonation:
Medium High
Alcohol Strength:
Low Medium
Finish Length:
Long Very long
Oxidation:
None Medium

Softly acidic, caramel-rich, and smooth with restrained fruitiness.

Does Flanders Brown Ale match your taste?

Start with a direction

Which taste direction appeals to you?

What gives Flanders Brown Ale its character

These structural drivers help shape its characteristic sensory profile.

  • High crystal addition adds caramel sweetness, deep amber colour and round malt richness.
  • Very high attenuation converts a large share of fermentable extract, strongly reducing residual sweetness and body while supporting alcohol formation and a dry finish.
  • Mixed fermentation producing layered lactic acidity and subtle funk.
  • A dextrinous mash leaves more non-fermentable extract, supporting greater body, residual sweetness and a longer finish.
  • Mixed fermentation contributes additional yeast-derived aroma complexity.
  • Finings remove suspended yeast and protein, improving clarity.
  • Low roast level adds a touch of colour and gentle coffee/chocolate notes with slight roast bitterness.
  • Vienna malt adds warm, honey-like malt character, increases colour and strengthens malt aroma.
  • Moderate grist intensity provides more extract, supporting somewhat higher gravity, body and alcohol strength.
  • Dark crystal provides intense dark-caramel and dried-fruit character in the malt aroma.

History

Originates from East Flanders with extended aging and blending traditions.

How Flanders Brown Ale compares to other beer styles

This comparison shows meaningful differences in sensory ranges and style character based on the GBI data.

Flanders Brown Ale vs Sour Ale

Compared with Sour Ale, Flanders Brown Ale has:

  • a darker color
  • more intense malt aroma
  • sweeter
  • less acidic
  • more bitter
  • a longer finish

Other differences:

  • Sour Ale can be hazier.
  • The hop aroma range of Sour Ale extends to lower intensities.
  • The yeast aroma range of Sour Ale extends to lower intensities.
  • Flanders Brown Ale can be more astringent.
  • Sour Ale can be more highly carbonated.
  • Sour Ale can have a stronger alcohol impression.
  • Flanders Brown Ale can be more oxidative.
  • Flanders Brown Ale has caramel, melanoidin and dark Roast malt notes.
  • Sour Ale can use American ale yeast; mixed Fermentation is part of the regular profile of Flanders Brown Ale, but optional for Sour Ale.
  • Sour Ale can use wheat as a grain; both styles include barley.
  • Flanders Brown Ale is bottle-conditioned.
  • Flanders Brown Ale can be aged in foeders, while Sour Ale can be aged in stainless steel.

Flanders Brown Ale vs Flanders Red Ale

Compared with Flanders Red Ale, Flanders Brown Ale has:

  • a darker color
  • more intense malt aroma
  • less acidic

Other differences:

  • Flanders Brown Ale can be sweeter.
  • Flanders Brown Ale has dark Roast malt notes, while Flanders Red Ale has toffee malt notes; both styles have caramel and melanoidin malt notes.
  • Flanders Brown Ale can have funky yeast notes. Flanders Red Ale has funky yeast notes. Both styles have sour Fermentation yeast notes.

Compare Flanders Brown Ale with another beer style

Choose any GBI beer style to compare sensory ranges and style character.

Want to explore the underlying data in more detail? Compare styles in the GBI Explorer →

Related styles

Other variants within the same style group as Flanders Brown Ale.

Best food pairings for Flanders Brown Ale

These food pairings complement the dominant sensory traits of Flanders Brown Ale.

  • Stews
  • Cheese
  • Caramel dishes

Service & Aging

Practical guidance for serving and handling Flanders Brown Ale.

Serving notes
Serve cellar cool
Pouring technique
Steady pour · Low foam
Aging potential
Ages 1–3 years
Common faults
Astringent acidity · Oxidation
Style details
  • Origin: Belgium — Originating from Belgian brewing traditions.
  • Glassware: Tulip — Stemmed tulip glass that concentrates aroma and supports a stable head; ideal for aromatic ales and Belgian styles.
    Tumbler — Simple straight-sided tumbler commonly used for lambic, farmhouse ales, and rustic or sour styles.
  • Serving: Bottle — Served from bottle.
  • Conditioning: Bottle-conditioned — Naturally carbonated in the bottle.
  • Aging vessel: Foeder — Aged in large wooden foeders.
  • Packaging: Bottle — Packaged in bottle.

Commercial examples of Flanders Brown Ale

The following commercial examples illustrate widely recognised expressions of Flanders Brown Ale in the market.

  • Petrus Oud Bruin
  • Liefmans Oud Bruin
  • VanderGhinste Oud Bruin

Flanders Brown Ale – Competition winners and medalists

Medal winners for Flanders Brown Ale from major beer competitions. Categories follow each competition's official classification and may include stylistically adjacent interpretations.

2025 competition results

Brussels Beer Challenge 2025

Oud Bruin (Flanders Brown Ale)

  • Gold – Monk's Café Grand Cru – Brouwerij van Steenberge , Belgium
  • Silver – Queue de Charrue Vieille Brune – Brasserie Vanuxeem , Belgium

Source: Brussels Beer Challenge ( official website )

Scroll to Top