Nissin Foods, the company that invented instant noodles, appears to have created an entirely new category with a hit product: cup noodles made with cold water.

Initial supplies of the handy meal – available in Spicy Kimchi and Chicken Salt Lemon flavours – sold out a week after hitting store shelves on July 20, according to Nissin. While the Tokyo-based company did not disclose sales figures, it had anticipated supplies to last one to two months.

“Nissin is accelerating the launch of innovative products and flavours tailored to increasingly diverse food cultures and focusing on balanced distribution across multiple channels,” Macquarie Equity Research analysts Linda Huang and others wrote in a report.

Ever since Nissin founder Momofuku Ando invented instant noodles in 1958, the basic formula has always relied on hot water, even for some varieties meant to be chilled before eating. The new product, which sells for 307 yen (US$1.93) apiece and was developed over five years, can be consumed after just five minutes, responding to growing demand for cool foods during hot weather.

Nissin, which has a market capitalisation of 869 billion yen, said its new product used a new patented process that resulted in smooth yet firm noodles.