Otafuku, one of the oldest oden restaurants in japan, has been heating up the same batch of broth every day since 1945, only adding more water to it as it evaporates. It may sound gross to most westerners, but it apparently makes oden stew taste amazing.

Oden is a traditional Japanese stew that is simmered in broth until served. It’s enjoyed by vegetable and meat lovers alike, as it can contain all kinds of ingredients, from from eggs, tofu and vegetables to shark meat, beef, fish balls and whale tongue, but the secret to its deliciousness is the broth. Many Japanese restaurants rely on master stock – a broth that has been repeatedly reused to poach or braise meats – to give their oden a rich flavor, but none have been using the same batch for longer than Otafuku, a Tokyo based eatery that has been reheating the same oden broth since the previous batch was lost in 1945.

Photo: [puamelia]/Flickr

With a history spanning over 100 years, Otafuku is the oldest oden shop in Tokyo, and its 65-year-old broth is nothing short of legendary. Just like the beef noodle soup at Wattana Panich, in Thailand, which has been simmering for 45 years, the broth at Otafuku is never thrown away. Instead, every night it is strained and removed from the copper pot it usually simmers in so the pot can be cleaned. It’s then put back in the pot and covered overnight, but not refrigerated. The next day, it’s heated again, with fresh ingredients and water being added as needed.

Many oden restaurants in Japan go to great lengths to preserve their broth for as long as possible, and a 10-year-old broth isn’t that unusual. However, the 65-year-old broth at Otafuku, in Tokyo’s Asakusa district is currently considered the oldest oden soup in existence.

According to Wikipedia, a master stock could be preserved indefinitely if great care is taken to ensure it does not spoil, and some restaurants in China – where the master stock is believed to have originated from – claim to have preserved their broths for hundreds of years, passing them on from generation to generation. However, these claims have never been validated so they could be nothing more than marketing. The age of the oden broth at Otafuku, on the other hand, is well documented.