What is an espresso decoction (signature)?

Decoction is a very ancient hot extraction technique — used for centuries in herbal teas, broths, and medicinal infusions — that competition baristas have reappropriated to integrate into advanced espresso preparations. In competition (WBC, national championships), rules allow the use of additional plant-based ingredients in the signature espresso, and decoction is one of the most sophisticated techniques for incorporating them. Practically, the barista prepares in advance — or live in front of the judges — a decoction obtained by boiling or simmering a plant ingredient (cardamom, cinnamon, licorice, lemongrass, dried hibiscus...) in water for several minutes. This decoction is then integrated into the espresso in several ways: as a partial replacement of the extraction water ('bypass blending' method), as a post-extraction addition in a precise ratio, or as 'layering' in the cup to create a progressive sensory experience. The advantage of decoction over a simple cold infusion or syrup is its aromatic concentration and depth: the lipid-soluble and water-soluble aromatic molecules in spices are better extracted at heat and with gentle movement. In professional practice outside competition, some avant-garde coffee bars offer signature espressos with decoction on their menu — for example an espresso with freshly prepared green cardamom decoction. The technique demands precision and repeatability: same decoction, same ratio, same temperature, same timing for impeccable service consistency.