Sour Beer: The Art of Tang

Sour beer is a broad category of beer characterized by an intentional acidic, tart, or sour taste. Unlike most modern beers, which are brewed in sterile environments with specific yeast strains, many sour beers are produced by allowing wild yeast and bacteria into the brew, either spontaneously or through inoculation.

The Chemistry of Sour: Bacteria and Yeast

The characteristic tang of sour beer comes from “wild” organisms that most brewers spend their lives trying to avoid:

• Lactobacillus: The same bacteria that makes yogurt tart. It produces lactic acid, which provides a clean, lemony sourness.
• Pediococcus: Another lactic-acid-producing bacteria that can provide a deeper, more aggressive acidity.
• Brettanomyces (Brett): A “wild” yeast that provides earthy, “funky” aromas often described as “horse blanket,” “leather,” or “pie crust.”

Major Sour Beer Styles

1. Lambic (Belgium)

Perhaps the most revered sour style. Brewed in the Pajottenland region of Belgium using spontaneous fermentation—leaving the brew open to the air to catch wild local yeast.

• Gueuze: A blend of old and young lambics, refermented in the bottle.
• Fruit Lambics: Lambics aged with whole fruit, such as Kriek (cherries) or Framboise (raspberries).

2. Gose (Germany)

A historic style from Leipzig.

• Ingredients: Brewed with at least 50% wheat, spiced with coriander, and—uniquely—salt.
• Profile: Bright, tart, and refreshing with a subtle salinity that makes it incredibly crushable.

3. Berliner Weisse (Germany)

Often called “The Champagne of the North” by Napoleon’s troops.

• Profile: Low alcohol, highly carbonated, and very tart.
• Tradition: Often served mit schuss (with a shot of raspberry or woodruff syrup) to balance the sharp acidity.

4. Flanders Red & Oud Bruin (Belgium)

The “burgundies of Belgium.”

• Aging: These beers are aged in large oak vats (foeders) for months or years.
• Profile: Flanders Red is vinegary and fruity (like balsamic), while Oud Bruin is maltier with notes of raisins and plums.

5. American Wild Ale

A modern, experimental category where US brewers use wild yeast and bacteria to create unique, often barrel-aged, sour beers.

Sensory Profile

• Appearance: Varies wildly depending on style, from the super-pale Berliner Weisse to deep red Flanders ales. Most are quite clear unless they are fruit-infused.
• Aroma: Expect “funk” (earth, hay), sharp citrus, vinegar, or intense fruit.
• Flavor: The primary note is acidity. It can range from a soft, refreshing zing to a sharp, puckering sourness.
• Mouthfeel: Often very dry and light-bodied. Carbonation is typically high.

Serving and Glassware

• Temperature: Best served cool, but not ice cold. 7–10°C (45–50°F) is ideal to appreciate the complex aromas.
• Glassware:
  • Tulip or Snifter: To concentrate the intense and funky aromas.
  • Flute: Perfect for carbonated styles like Gueuze or Berliner Weisse.

Food Pairing

• Creamy Cheeses: The acidity of the beer cuts through the fat of Brie or Camembert perfectly.
• Salads: Pairs well with goat cheese and fruit-based dressings.
• Seafood: Excellent with fatty fish or anything served with lemon.
• Desserts: Fruit sours are legendary with cheesecake or dark chocolate.