Tianmianjiang

While both are sweet, dark sauces, tianmianjiang is a traditional fermented wheat-and-soybean paste from Beijing, whereas hoisin sauce typically includes added spices, garlic, and sweet potato starch. Tianmianjiang literally translates to "sweet flour sauce" and relies purely on the fermentation of the grains for its deep umami flavor. It is most famously served as the primary dipping condiment for Peking duck.

The traditional process involves making a dough from wheat flour, steaming it, and then fermenting it with a starter culture or soybeans. This mixture is aged and sweetened over time, creating a thick, savory-sweet paste. The slow fermentation process is what gives the sauce its characteristic earthy and rich profile that defines Northern Chinese cuisine.

If you cannot find authentic Beijing sweet bean sauce, a mixture of hoisin sauce and a little fermented yellow soybean paste (doujiangjiang) can approximate its flavor. However, for authentic Peking duck preparation, many chefs recommend ordering true tianmianjiang online to get the exact earthy sweetness. Sweet bean sauce from brands like Lee Kum Kee are widely available substitutes.

Yes, in Western markets, Tianmianjiang is almost always marketed as "sweet bean sauce" or "sweet wheat paste." Despite the name "sweet bean," the primary grain used is actually wheat flour rather than just soybeans. It remains a foundational flavor profile in Northern Chinese dishes like zhajiangmian.