Pi county (now Pixian) in Sichuan province has been the production centre for the most highly regarded doubanjiang for centuries — the Pi county variety is considered the benchmark, its quality coming from the specific Sichuan chilli varieties, the locally made broad bean paste, and a multi-year fermentation process (premium versions are aged 3–5 years). The result: a paste of extraordinary depth, with a brick-red colour, a pungent, fermented aroma, and a complex flavour of chilli heat, fermented bean savouriness, and a slightly sweet background.
Doubanjiang — fermented broad bean and chilli paste — is the foundational flavouring of the Sichuan kitchen. More than any other single ingredient, doubanjiang defines the aromatic and flavour profile of Sichuan cooking: its deep, complex, fermented savouriness; its chilli heat; its aromatic richness. Dunlop describes it as the soul of Sichuan cooking and the ingredient without which many of the tradition's most important preparations cannot be made. A pot of quality doubanjiang in the refrigerator is the beginning of the Sichuan kitchen.
Doubanjiang's flavour chemistry combines fermented broad bean's glutamic acid (umami foundation), the chilli's capsaicin (heat), the chilli's carotenoid pigments (colour and flavour), and the complex Maillard products of the fermentation (a range of volatile compounds including aldehydes, ketones, and esters). When fried in oil, the fat-soluble carotenoids and capsaicin carrier molecules dissolve into the oil phase, while the water-soluble glutamic acid compounds remain in the paste — the combination of fat-carried and water-carried flavour compounds distributes through the entire dish as both a liquid and a fat component.
**Quality selection:** - Pi county (Pixian) doubanjiang: the gold standard. The label should say Pí Xiàn Dòubànjiàng (郫县豆瓣酱). The three-year aged version is considered significantly superior to the one-year. - Colour: brick-red to deep red. Not brown-black (over-fermented, too bitter). - Smell: complex, deeply fermented, chilli-pungent but with a sweet background note. - Texture: chunky — the whole broad bean pieces and chilli pieces are visible in a premium doubanjiang. Smooth, homogeneous doubanjiang is the commercial, inferior version. **The frying technique:** Doubanjiang is always fried in oil before any other liquid ingredient is added — this is the extraction technique that releases its fat-soluble aromatic compounds into the oil. Frying in cold or insufficiently hot oil produces a paste that tastes sharp and raw; frying correctly produces a deeply aromatic, complex base. 1. Oil (2–3 tablespoons) in a wok over medium-low heat. 2. Add doubanjiang. Fry, stirring constantly, for 3–5 minutes. 3. The paste darkens slightly. The oil turns deep red-orange from the chilli's fat-soluble carotenoids. 4. A deeply complex, fragrant smell develops — the raw fermented edge cooks off and the aromatic depth emerges. 5. The correct endpoint: the oil around the paste is a vivid, translucent red-orange and the paste smells deeply of fried chilli and fermented bean — complex and fragrant rather than raw and sharp. **After frying:** The other aromatics (garlic, ginger, Sichuan pepper) are typically added to the frying doubanjiang and fried briefly together before the protein and liquid are added. This combined frying stage is the flavour foundation of many Sichuan dishes. Decisive moment: The colour of the oil after 3–5 minutes of frying the doubanjiang. Correctly fried: the oil is a brilliant, transparent red-orange — the chilli's soluble carotenoids (capsanthin and capsorubin) have been extracted into the fat phase. This red oil is the visual indicator that the aromatic extraction has occurred. Oil that is still its original colour after 3 minutes: the heat was insufficient and the extraction was incomplete. Sensory tests: **Sight — the oil colour:** A spoonful of the oil after correct frying of doubanjiang: vivid, transparent red-orange — the Sichuan 'red oil' that is the visual signature of the cuisine. **Smell — the transformation:** Raw doubanjiang: intensely pungent, sharp, fermented. After 3–5 minutes of frying: the sharpness has cooked off and a deeper, more complex aromatic has developed — still pungent, still fermented, but with a cooked richness that the raw paste lacks. The smell at the correct endpoint is the smell of the Sichuan kitchen.
- The red oil produced by frying doubanjiang is used as a finishing oil in many Sichuan preparations — spoon a tablespoon of this red oil over a finished dish for both flavour and colour - Doubanjiang stores refrigerated for 12 months minimum. It does not require airtight storage but should be kept with the oil level above the paste surface - Different brands vary significantly in salt content — taste before using and adjust fish sauce/soy sauce accordingly
— **Burnt, bitter paste:** Heat too high for the frying — doubanjiang's sugars and amino acids burn rapidly at high heat. Medium-low heat is required. If the paste has burnt: discard and start again. — **Raw, sharp taste in the finished dish:** Insufficient frying time. The paste needs 3–5 minutes of sustained frying to complete the aromatic transformation.
Fuchsia Dunlop, *Land of Plenty* (2001); *Every Grain of Rice* (2012); *Land of Fish and Rice* (2016); *The Food of Sichuan* (2019)