Turbid mashing

What is actually happening

Portions of cloudy, starch-laden wort are drawn off at intervals, heated separately and returned, in a sequence that leaves a substantial fraction of the carbohydrate unconverted.

Ordinary brewing maximises conversion. Lambic deliberately does not, because Brettanomyces can slowly consume what Saccharomyces cannot — and a fermentation lasting three years needs something left to eat.

Styles where this step is decisive

• Lambic5–6.5% ABV

  Spontaneously fermented Belgian wheat beer, matured in oak for years — funky, acidic, dry and unlike any other beer.

• Gueuze5–8% ABV

  A blend of young and old lambic, refermented in bottle — intensely complex, bone dry and Champagne-like in its carbonation.

• Fruit lambic5–7% ABV

  Lambic refermented on whole fruit — traditionally sour cherry or raspberry — producing a dry, tart, intensely fruity beer.

Related steps and concepts

• Spontaneous fermentation — The fermentation it feeds.
• Mashing — The conventional approach it inverts.