Mark Bittman says that “an all-purpose sauce from Japan, ponzu is the rough equivalent of vinaigrette.”; ponzu is a citrus flavored soy sauce which can be used as a dip, marinade, or salad dressing when mixed with a little oil. The ingredients for ponzu sauce are, clockwise from top: soy sauce (shoyu), bonito flakes, bottled yuzu juice, kelp (konbu), ruby red grapefruit, mirin.
The first time I made this I was able to obtain a single fresh yuzu, which are in season in the winter. Since it is now spring, and yuzus are out of season, now I have some bottled yuzu juice to make ponzu sauce next time. Yuzu are yellow but unlike lemons they are round and unevenly dimpled (see picture below). They are in season usually around November and December. They will keep one to two weeks fresh (longer in the refrigerator), and can be frozen for long term storage, so if you find some for a good price, buy several and freeze them. Defrost in the refrigerator before juicing.
Source: Modified from “Yuzu-Flavored Ponzu Sauce (Ponzu)” from “The Sushi Experience” by Hiroko Shimbo”
- 2 Tbsp mirin
- 1/2 cup soy sauce (shoyu)
- 1/2 cup yuzu juice* or a mixture of half yuzu juice and half freshly squeezed grapefruit juice. If yuzu isn’t available, then substitute another citrus juice such as lemon, lime, or grapefruit.
- 1 inches konbu (kelp)
- 1/2 cup shaved bonito fish flakes (katsuobushi)
Put mirin in a small saucepan and bring to a simmer over medium heat. Add the soy sauce and cook over low heat for 5 minutes. Remove from heat and set aside. When it has cooled, pour the sauce into a clean jar with a tight fitting lid, and add the yuzu juice, grapefruit juice, kelp, and bonito. Refrigerate, covered with a tight lid for preferably for one week (if you are rushed for time, at least let it marinate for 2 hours). Strain the ponzu sauce; discard the kelp and bonito flakes. Keep in the refrigerator; after about 2 months it loses flavor.
* Each yuzu makes about 1 to 2 tablespoons of juice, so if your yuzu are very juicy you might get nearly a half cup from 4 yuzu.