Souring
Lactic-acid-producing bacteria can create clean, refreshing tartness. Different methods decide when and how that acidity develops.
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Beer styles · Sour & wild
Sour beer & wild fermentation: when acidity is part of the plan.
Sourness in beer can mean something has gone wrong — or that everything has gone exactly to plan. The clue is context. Some beers are designed around tartness, mixed cultures, wood and long ageing from the very beginning.
Mixed fermentation
Brewers may use conventional yeast alongside bacteria and other yeasts, letting complexity build slowly.
Spontaneous fermentation
Instead of pitching one selected culture, wort is exposed to the local environment and fermentation develops from naturally present microbes.
Fast sour vs slow sour
Acidity can take a day or several years.
Kettle souring creates acidity before the main fermentation and can be relatively quick and controlled. Mixed and spontaneous fermentation may continue changing in wood or bottle for months or years, building flavours that go well beyond simple tartness.
The useful families
“Sour beer” covers some very different ideas.
Kettle sour
A modern route where acidity is created quickly before the main fermentation. It can produce clean, bright tartness without the long ageing associated with traditional mixed-fermentation beer.
Gose
A tart wheat-beer family traditionally associated with Leipzig, often with salt and coriander adding savoury and citrusy edges.
Berliner Weisse
Very pale, light and sharply refreshing, with acidity doing more work than bitterness.
Flanders red / brown
Matured with mixed cultures and often wood, building acidity, fruit and deeper aged character over time.
Lambic & gueuze
Spontaneous fermentation around the Brussels/Pajottenland tradition, followed by long maturation; gueuze is made by blending lambics of different ages and bottle-conditioning them.
Fruit sour beer
Fruit may be added to an already sour base, creating genuine fruit flavour on top of fermentation-derived acidity.
What does “funky” mean?
Usually a bundle of earthy, leathery, farmyard or fruit-skin aromas — not one flavour.
Brettanomyces and long mixed fermentation can produce aromas that seem unusual beside clean lager or pale ale. In the right beer they add complexity; in a beer that was meant to stay clean they may indicate contamination. Again, context decides whether the same sensory clue is a feature or a fault.
Put sourness into context