Tsume is a sweet glaze used in Edo styled sushi for cooked ingredients, and is not comply used on raw fish. The word tsume comes from nitsume (reduction) and is either made from the broth used to poach sea eel and or hamaguri clams.
Fundamental in sushi and in the west you rarely find it. Foreign sushi chefs all over the globe use a sweetened sauce (bottled) to cover their toaster oven cooked frozen eel. Most foreign chefs use granulated or liquid instant substitutes found in Asian Markets, and its the sweetness that attracts most aficionados.
But American sushi chefs use Tsume to dress everything from avocado-based rolls to tamale and that is disgusting. The best time you are in your organic section at the market stay away from these sorts of things.
Mr. T establishes a tare, a sauce namely called Tsume (sushi jargon), which is dark sweet sauce served over anago. The Tsume recipe varies from chef to chef, and it is similar to a chef’s own sauces in French cooking. Here it is seen in the cooking stages as the simmering happens slowly as the sauce reduces.
Winter Colored Tsume:
Tsume is always homemade by any serious sushi chef and never bought from a supermarket. Each season eel produce a different viscosity (diet and habits) and so in the winter you’ll find the sauce more intense and darker, whereas in the spring the color is slightly lighter.
Tsume is traditionally made with the reduced stock of boiled conger eels (anago) and other ingredients such as sugar, shoyu and sake, all which depend on chef by chef. It takes some days of cooking time but the end result is kept for a season until it runs out and the process begins all over again next winter. This batch is for summer.
Summer coloured Tsume: