An (餡 — sweet bean paste) is the foundational ingredient of Japanese confectionery in the way that crème pâtissière is the foundation of French patisserie — a base from which an entire system of preparations extends. Its preparation from azuki beans (小豆 — literally "small beans") or white beans (白花豆) appears in Japanese culinary records from the eighth century CE, when it was brought from China as part of Buddhist temple food culture. The technique of sweetening and working the paste reached its current form during the Heian period. There is no equivalent in Western confectionery — a paste made from legumes, sweetened, and used as a primary filling for sweets is entirely outside the Western tradition's experience.
An is made from dried azuki beans simmered until fully soft, then worked with sugar to a specific consistency. There are two primary forms:
An pairs with matcha because their flavour profiles are complementary counterpoints: matcha is bitter, vegetal, umami-forward; an is sweet, earthy, mineral. Together they produce a complete flavour experience that neither achieves alone. The pair is ancient — it has been the foundation of the tea ceremony for four hundred years — and it is correct.
1. The initial simmer must discard the first water (akuluki — removing the bitter compounds from the azuki skin). Bring to a boil, discard water, add fresh water, continue simmering. 2. Cook to complete softness — no resistance when pressed between fingers. Under-cooked beans produce a grainy texture in the final paste regardless of how finely they are sieved. 3. The drying stage (working the sieved paste over low heat to evaporate moisture) determines the final consistency — a correctly dried koshi-an holds its shape when a spoon is dragged through it and the line slowly disappears. Too wet: the confection will not hold shape. Too dry: it cracks when worked. 4. Temperature during working: the paste is worked over the heat to dry it — the heat must be low enough that the sugar does not caramelise (which would change the colour and flavour permanently) Sensory tests: - **The finger press:** Correct cooked azuki beans offer zero resistance — they dissolve under very light pressure. Any remaining firmness means more cooking is needed. - **The dry an test:** Work cooled an between your palms — it should be smooth, slightly plastic (it holds an impression briefly before springing back), and not tacky. Tacky means too much moisture. Cracking means too dry. - **Flavour of koshi-an:** Clean, earthy sweetness — like the smell of rain on dry earth, slightly mineral, with a restrained sweetness that does not shout. If the bitterness of the skins is perceptible, the sieving was insufficient.
Japanese Confectionery Deep: Wagashi, An, Mochi & the Seasonal Sweet Tradition