Corn Silk, Corn Cobs, All Kept: How One Shirokanetakanawa Restaurant Turns Scraps Into a Soup
At Japanese restaurant "Watanabe," the owner roasts corn until fragrant, then simmers it whole—silk, cob, and all—drawing out flavor with nothing but premium Rishiri kelp. The result is a suringashi drink, served hot or cold, that shows how food-saving can still be refined cuisine.
Once the kernels are shaved off, the cob and silk usually go straight into the trash. At "Shirokanetakanawa Watanabe," a fully reservation-only Japanese restaurant in Tokyo's Shirokanetakanawa neighborhood, the technique demonstrated this time keeps everything—skin, core, and all—simmering together in the pot.
This is an installment of "Rescue Recipe," a running feature in Ryori Tsushin magazine, this time focused on summer's seasonal star: corn. With Japan generating about 4.64 million tons of food waste annually, the series invites chefs to demonstrate ways to minimize waste—and this round, corn takes the spotlight, with the restaurant owner himself leading the demonstration.
The owner hails from Yamanashi Prefecture, growing up surrounded by food—his father ran a coffee shop, and his mother's family owned a traditional Japanese sweets shop. After high school, he went on a working holiday in Australia, then returned to work at "Ken" near Tokyo Gakugei University. In 2014, he opened the Japanese restaurant "Suzushiro" in Sangenjaya, which closed in 2019. Watanabe, his current restaurant, opened in 2021.
Rather than boiling the corn straight, the technique starts with a gentle roast to coax out a smoky char, adding a layer of toasted aroma on top of the natural sweetness. The broth relies solely on premium Rishiri kelp—no bonito flakes added—because the corn itself is flavorful enough without extra layering. The real trick is simmering the shaved kernels together with the cob and silk, adding just enough water to cover everything along with the kelp, then letting it cook on low heat for ten minutes. The umami hides in the parts usually thrown away.
Whether to strain it depends on the texture you want: skip straining, and you get the full texture of ground vegetable bits; strain it, and you get something lighter and cleaner—though straining requires careful pressing with a wooden spatula so the umami doesn't get left behind in the strainer. This version was strained, resulting in a smooth texture that works hot or cold, drinking more like a beverage than a traditional soup.
The ingredients for four servings are simple: three ears of corn, corn silk to taste, 10 grams of kelp, and a pinch of salt. After shaving off the kernels with a knife, combine them with the cob, silk, kelp, and just enough water to cover everything in a pot. Simmer on low heat for ten minutes, and it's done.
Shirokanetakanawa Watanabe is located at 1F Lions Mansion Shirokane Higashi, 1-29-9 Shirokane, Minato-ku, Tokyo. Phone: 03-6277-1733. Open 17:00 to 24:00, fully reservation-only, with irregular closures. A 1-minute walk from Shirokanetakanawa Station.
