
Hot water is the hottest water around.
Bottled waters have long been the rage in Japan, with store shelves lined with all kinds of flavors and levels of carbonation to appeal to increasingly health-conscious consumers. And on 1 November, Asahi Soft Drinks released yet another new take on an old classic with the only bottled hot water on the market.
▼ It’s called Oishii Mizu Tennensui Sayu.
This isn’t just any hot water though. It’s what is known as “sayu” in Japanese as opposed to “oyu” which is the normal term for hot water. Oyu is water that has been heated to a temperature of 40 degrees Celsius (104 degrees Fahrenheit) or so, whereas sayu is considered water that has been brought to a boil and then cooled to around 50 degrees Celsius (122 degrees Fahrenheit).
As you can probably imagine, the boiling process helps to remove impurities and thus makes sayu a healthier alternative to oyu, especially if you’re getting it from a tap. Sayu is said to be great for improving blood circulation and promoting healthy digestion.
In the case of Asahi’s Oishii Mizu Tennensui Sayu, natural spring water is directly bottled and then warmed to temperatures between 50 and 60 degrees Celsius (122 and 140 degrees Fahernheit)…which, come to think of it, doesn’t make this sayu. It really is just any hot water after all.
In fairness to Asahi, there isn’t a strict definition of what exactly “sayu” is and since the source is natural spring water served at the same temperature as sayu, there’s still a fair chance that the health benefits of this Oishii Mizu Tennensui Sayu hold true. Either way, customers in Japan have really been willing to take the plunge as sales have exceeded expectations and the social media response has been 10 times that of other Asahi products.
▼ As you can see by the thrilled look on his face, our writer Ahiruneko loves it too
This is in contrast to 2014, when Asahi previously tried to market bottled hot water. At that time it was released with the more straightforward name “Hot Tennensui” and sales were too lackluster to continue. However, with people looking increasingly for healthier beverages and the more intriguing name of “Sayu”, Asahi seems to have found the recipe for success.
Reaction in online comments was generally positive too, but not everyone was totally convinced to go out and buy some hot water.
“So if you cool it down, it just becomes water.”
“They should make flavored versions. That could be good.”
“Please sell more ramen broth instead.”
“Great timing. People are tired of stuff with additives and there’s no competition yet.”
“That’s useful when you want to make soup quickly.”
“It’s good because it isn’t sweet and more refreshing than tea.”
“Sounds pretty good for winter.”
“I saw it today and bought one. It was good and soothed my throat.”
“I have a weak stomach so that sounds perfect.”
“I’m not paying money for hot water!”
“I can just drink the water coming out of my shower in the morning.”
While one theoretically could drink the water that comes out of the shower, there are obvious logistical problems to consuming hot water that way alone. At the very least, Oishii Mizu Tennensui Sayu provides the convenience of getting heated water on the go, so maybe it is worth checking out for 113 yen (US$0.80) per 340-milliliter (11-ounce) bottle.
Source: Oricon News, Asahi Soft Drinks, My Game News Flash, Mizu Select
Photos ©SoraNews24
● Want to hear about SoraNews24’s latest articles as soon as they’re published? Follow us on Facebook and Twitter!



Asahi now sells hot bottled water in Japan as an alternative to coffee or tea
Is it OK to drink bottled water after the expiration date in Japan?
Transparent coffee! We taste-test Asahi’s Clear Latte, marvel at Japanese drinks wizardry
Japanese vending machines now have the strangest thing we never knew we needed: hot bottled water
Japanese vending machines set to become cooler than ever by selling sub-zero soft drinks
12-year-old foreign tourist missing in Japan, police asking for help finding her [Video]
Study finds hundreds of people in Indonesia legally named after Naruto, Inuyasha, other anime stars
Teen girl in Japan refuses to be victim, personally escorts train pervert to police for arrest
The Japanese city where ordering grilled chicken doesn’t guarantee you’ll actually get chicken
Japanese airlines set to cut fuel surcharges for international flights in September and October
Google’s first Google Store outside the U.S. is now open in Tokyo
Delta Airlines adds first nonstop flight between Japan’s Narita Airport and U.S. in seven years
Ride a tram that survived the atomic bombing of Hiroshima on a new limited-time history tour
Watch a sumo bout inside Tokyo Tower, at a new restaurant endorsed by two yokozuna
Hello Kitty x Godzilla Happy Meals are coming to McDonald’s, but not in Japan [Video]
Japanese toilet aims to attract foreign tourists but not everybody is happy about it
New Japanese vending machine at Shinkansen station sells cups of ice on platform
Japan’s new beer glass is designed to force you to drink…water [Video]
Studio Ghibli adds new Jiji’s baby plush toy to its anime merchandise range in Japan
End of a manga era as Weekly Shonen Jump’s circulation drops under one million
Anime fan in Japan arrested for ordering and cancelling over 4.3 billion yen in anime merch
Beautiful Totoro bonsai figure needs no watering, makes soothing rain showers whenever you want
This beautiful rural Japan river is a great alternative to touristy summer retreats [Photos]
Beautiful off-the-beaten-path spot near samurai castle in rural Japan looks like a Monet painting
Tokyo subway installing new ticket gates that don’t accept payment through Suica or other IC cards
Japan now has human refrigerators inspired by Japanese vending machines
Hatsune Miku collaborates with Hokusai’s art in new Vocaloid ukiyo-e illustration series [Pics]
New Shinkansen luggage drop-off system begins in Japan, making train travel even easier
Studio Ghibli releases anime T-shirts that pay homage to one of Hayao Miyazaki’s most personal films
Air-conditioned dress shirts arrive in Japan to save working professionals from sweltering heat
Japanese Shinkansen becomes an overnight hotel for three nights this summer
Pokémon Center Online designates first Pokémon items that will require Japanese ID card to buy
99-year-old woman rescued while attempting to climb Mt. Fuji
Japan announces sudden 400-percent increase in visa fees for foreigners entering the country
Japan’s human washing machines will go on sale to general public, demos to be held in Tokyo
Studio Ghibli has a new anime out, and there’s only one place in the world where you can see it
Starbucks Japan releases new drinkware and goods for Valentine’s Day
Starbucks Japan releases new sakura goods and drinkware for cherry blossom season 2026
Japan’s newest Shinkansen has no seats…or passengers [Video]
Japanese ninja certification exam attracts 131 candidates from Japan and abroad
Salomon releases Japan-exclusive Mt. Fuji hiking gear that doubles as an amazing souvenir
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
Starbucks Japan sells a new water bottle with bonus extras to spark joy
Why is it so hard to find hot sake in convenience stores in Japan?
Leading bottled water brand in Japan goes label-free to reduce waste, angers many
Coca-Cola Japan are testing “fill your own bottles” water dispensers to help reduce plastic waste
7-Eleven Japan now sells canned water, but does funky packaging mean funky flavor?[Taste test]