The economy may be heating up, the weather outside may be chilly, but Prime Minister Shinzo Abe sticks to the middle of the road: lukewarm water.

In a Tuesday Facebook entry from the prime minister's office, Abe wrote that the contents of the thermos bottle he regularly brings to the Diet is "tepid water heated slightly above body temperature."

"Water prepared at the Diet is half-filled with ice and too cold, and it isn't suitable for budget committee deliberations, which begin in the morning and continue all day," Abe wrote.

Abe's first prime ministership, which was clouded by scandal, started in September 2006, but he resigned abruptly the following year, citing an intestinal disease. Upon becoming prime minister again in December, he claimed his health had improved and he was fit to hold the position again.

However, the contents of the thermos have been the target of media speculation, since Cabinet members and lawmakers typically settle for the ice water prepared in the Diet.

"Abe's bottle," as the thermos has been dubbed, is sold by the Afternoon Tea Living brand chain for approximately ¥3,000.

The prime minister wrote that he borrowed the thermos from his wife, Akie.

"I endured the budget committee deliberations again today with my bottle," he said.