Self-stirring saucepan has foodies in a spin

February 28, 2013


TOBE, Ehime Prefecture--A saucepan that causes its contents to spin when heated is selling fast in Japan and promises to become the next big thing for the cook who has better things to do than stand and stir.

Called the "Kurukuru nabe" (swirly pot), the saucepan has a notched insert that acts like an impeller and induces a low-speed whirlpool in boiling water.

This not only keeps pasta on the move, it also causes the scum from soup or boiling vegetables to gather in the middle where it can be skimmed off more easily.

And what's more, the gadget causes boiling water to froth in the center of the pan, making it less likely to boil over.

Its developer has been astonished at the demand since the item went on sale in January, registering 5,000 orders so far from what is currently the sole outlet, the website.

"I just thought it was a fun idea, and ran with it. I never dreamed of this overwhelming response," said inventor Hideki Watanabe, a 45-year-old dentist from Tobe.

Watanabe got the idea when smoking one day in his kitchen. He watched the smoke rising toward a ventilation fan and then shifted his gaze to a saucepan.

"Wouldn't it be great," mused the man of self-confessed limited culinary skills, "if noodles and vegetables could stir themselves."

He tried fixing slats to a saucepan to induce a whirlpool. He worked using the dental plaster he knew so well from his day job and stuck a dozen or so plaster blades around the inside. Then he added water and noodles--and watched in satisfaction as the contents began to turn.

Watanabe immediately applied for a patent. He then posted a clip of the prototype on YouTube showing colored beads swirling around in boiling water. By May, the clip had racked up more than a million views.

E-mail messages flooded in from around the world, from Europe, the United States, even from Israel and Dubai. Watanabe received more than 100 from correspondents offering to help manufacture what they called a marketable product. Most of the messages were in English, but some people took the trouble to write in halting Japanese, doing their best to get their bid understood. Watanabe responded to every inquiry, but had to use translation software.

Despite the show of overwhelming enthusiasm from potential partners, finding the right one proved difficult. Many ultimately turned Watanabe down because of the difficulty of working with metal and creating pots with finely machined grooves.

Through trial and error, Watanabe eventually honed his design to an easily cleaned one with two components: a conventional saucepan with a separate grooved rig, which rests inside.

When a regular pot is heated, the water adjacent to the side rises vertically by convection. But the grooved sides of the Kurukuru Nabe direct the rising water to rise diagonally, ultimately creating a circular whirlpool.

In October 2012, a specialist IT and sheet-metal company known for producing highly polished components for Apple computers and portable music players agreed to become Watanabe's production partner. Toyo Rikagaku Kenkyusho Co., based in Tsubame, Niigata Prefecture, is a leading producer of items with a mirror-like finish, an area it gained extensive experience in when specializing in treating high-shine tableware.

"We had never worked with pots before," said a company official. "We tweaked the design to make sure we got a strong swirling movement going."

On Jan. 6, the 18 cm x 15 cm Kurukuru Nabe went on sale through the Web retailer, priced at 9,800 yen ($105). It became an instant hit. The manufacturer is producing 1,000 sets per month, but plans are afoot to expand production and even to go global, launching the product in seven countries, including in the United States.

"I think it is an interesting idea that makes great use of a natural phenomenon," said Kyozo Ayukawa, professor emeritus of fluids engineering at Ehime University, when The Asahi Shimbun asked him to comment on the underlying physics.

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Soba noodles spin in a whirlpool induced by the self-stirring pot. (Daisuke Hatano)

Soba noodles spin in a whirlpool induced by the self-stirring pot. (Daisuke Hatano)

  • Soba noodles spin in a whirlpool induced by the self-stirring pot. (Daisuke Hatano)
  • Dentist Hideki Watanabe shows off his invention, a self-stirring pot. (Daisuke Hatano)

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