Japan — ankake technique has been part of Japanese cooking since at least the Heian period, when kuzu starch was used as a sauce thickener in court cooking. Katakuriko (originally made from the katakuri lily bulb, now from potato starch) became the standard thickener through the Edo period. The technique's visual refinement — the transparent, glossy sauce — aligns with Japanese aesthetic values (transparency, shine, clarity) that run throughout the cuisine.
Ankake (あんかけ, 'covered in sauce') is the Japanese technique of thickening a dashi-based sauce, soup, or dressing with katakuriko (potato starch) or kuzu (arrowroot) to create a glossy, translucent, clinging sauce that coats ingredients without obscuring them. The term 'ankake' describes the resulting sauce (the 'an') and the technique of pouring it over (kakeru) the prepared ingredient. Ankake appears across Japanese cuisine: ankake tofu (silken tofu with warm dashi-soy-mirin sauce, thickened and poured over), ankake udon (broth thickened for cold-weather warming effect), ankake chahan (fried rice with thickened egg-sauce poured over), and ankake gyoza (pan-fried gyoza with a gelatinous, richly flavoured sauce). The technique is valued for its versatility and visual effect — the glossy, translucent sauce draped over food is visually distinctive.
Ankake sauce's flavour is dependent entirely on its dashi base — properly made, it tastes of the dashi itself with the seasoning additions, barely altered by the starch. The starch's contribution is textural: it creates a specific viscosity and coating property that changes how the sauce delivers flavour to the palate — the thickened sauce clings to the tongue longer than a thin broth, allowing the dashi's umami and the seasoning's depth to develop across the full width of the palate.
The starch: katakuriko (potato starch) is preferred for its clean flavour and transparent finish when cooked; kuzu (arrowroot) is higher-end and produces a more gelatinous texture; cornstarch works but produces a slightly cloudier result. The method: dissolve starch in double its volume of cold water; whisk this slurry into a simmering sauce base; stir constantly while bringing back to a simmer; the sauce thickens as it reaches boiling and becomes transparent within 30 seconds of reaching temperature. Remove from heat immediately — continued cooking causes breakdown and thinning.
The 'an' of ankake should have a specific viscosity: loose enough to pour and flow freely when warm, thick enough to coat the back of a spoon. To test: dip a spoon and draw a line through the coating — it should hold the line for 3–4 seconds before closing. For tofu ankake at a top Japanese restaurant (Kikunoi, Kyoto), the ankake sauce is based on the day's premier dashi and thickened to a translucent veil — the sauce drapes the tofu with a quality comparable to a French nappe-style sauce. Add a few drops of yuzu juice to ankake sauce immediately before serving — the citrus aroma lifts the warm, savoury sauce and creates a more complex sensory experience.
Adding starch to a boiling sauce — causes lumps; always make a cold-water slurry first. Over-cooking after adding starch — the sauce thins again after the starch breaks down from excessive heat. Under-seasoning the base before thickening — the starch concentrates flavour slightly but cannot correct seasoning errors. Allowing the sauce to cool too much before using — ankake sauce must be served immediately or kept warm to prevent setting into a gel.
Washoku — Elizabeth Andoh; Japanese Cooking: A Simple Art — Shizuo Tsuji