
With just four quick steps and a very special ingredient, anyone can make this spectacular fluorescent jelly!
Over the past year, Japanese Twitter users have been trying their hand at a luminescent dessert they’re calling “Cherenkov Jelly“. Underwater nuclear reactors give off a blue glow due to Cherenkov radiation, and this sweet does exactly the same thing, only using a different ingredient to bring out its fluorescence under the glow of a backlight.
Using just a few simple ingredients, you too can create the mysterious looking sweet at home. The one secret ingredient you can’t do without, however, is tonic water, as the presence of quinine in the drink makes it glow under ultraviolet light.
▼ If you hold a black light over any bottle of tonic water, you’ll be able to see that it glows on its own.
As jelly crystals aren’t easy to find in Japan, we made the jelly from scratch, using the following ingredients.
- Gelatin leaves
- Tonic water
- Mint leaves
- Curaçao liqueur
- Sugar or Japanese gum syrup
If you’re able to use jelly crystals, then the recipe becomes a whole lot easier, as you already have all the gelatin, sugar and flavour you need. Simply make the jelly as usual, preferably using a blue-coloured mix for a brighter glow, and use tonic water instead of regular water to obtain the fluorescent result.
Method:
1. Soak 10 gelatin leaves in water for 3 minutes until soft.
2. Bring 300 millilitres (10 ounces) of tonic water to the boil and add 1/4 cup sugar and 1/2 cup of mint leaves.
3. On a low heat, add the softened gelatin leaves until dissolved.
4. Turn off the heat and add another 200 millilitres (6.8 ounces) of tonic water. Remove the mint leaves and stir in 1/2 cup of Curaçao liqueur.
5. Stir and let stand for 15 minutes until cool.
Then all you have to do is pour the cooled mixture into little cups, moulds or glasses and leave them in the refrigerator for about four hours until set.
We used several types of glasses to make our jellies, so we could see how the different shapes would glow in the dark. Under natural light, they all looked like ordinary desserts.
▼ But under ultraviolet light, they shone brightly with a beautifully eerie glow.
While the glow-in-the-dark treats are perfect for Halloween, they can be used year-round as a fun way to surprise friends and guests at all types of parties and get-togethers. Fluorescent jellies are a memorable way to end any meal!
Photos ©RocketNews24















Don’t throw away the bones! How to make Japanese Christmas KFC soup【RocketKitchen】
How to make a mouth-watering Japanese beef bowl in just five minutes 【RocketKitchen】
How to make your own Pikachu Burgers!【RocketKitchen】
Silicone testicle covers banned from Japanese sauna following cups being left behind and on shelves
Visiting Japan’s one-and-only, and only-for-a-limited-time, Dragon Ball noodle restaurant[Photos]
Studio Ghibli now sells Ursula’s backpack from Kiki’s Delivery Service at its anime shop in Japan
Starbucks Japan unveils new sakura cherry blossom collection for hanami season 2026
7-Eleven Japan now sells bagels…cooked in bamboo steamers
The Japan Poop Society is making movements to protect people’s health
Taste-testing Japan’s real-world Dragon Balls and Senzu Beans at Marugame Seimen
Japan’s cherry blossom season predicted to start earlier than we’d thought, especially in Tokyo
Tokyo Station staff share their top 10 favorite ekiben
In Nakano Broadway, Giant Soft Serve Ice Cream Eats You!
Is Tokyo Station’s startlingly expensive wagyu bento boxed lunch worth its high price?[Taste test]
One Piece creator has hidden secret of anime treasure’s identity in chest at bottom of real-world ocean
Japanese government planning higher ticket prices for foreign tourists at Tokyo National Museum
Live-action One Piece’s Luffy teaches Sesame Street’s Elmo a Japanese word for friendship[Video]
Sakura Festival in Chiyoda mixes illuminations, boats, music, and Rilakkuma in the heart of Tokyo
Starbucks Japan releases first-ever Hinamatsuri Girls’ Day Frappuccino
Japan’s newest Shinkansen has no seats…or passengers [Video]
Starbucks Japan releases new sakura goods and drinkware for cherry blossom season 2026
Foreigners accounting for over 80 percent of off-course skiers needing rescue in Japan’s Hokkaido
Super-salty pizza sends six kids to the hospital in Japan, linguistics blamed
Starbucks Japan unveils new sakura Frappuccino for cherry blossom season 2026
Foreign tourists in Japan will get free Shinkansen tickets to promote regional tourism
The 10 most annoying things foreign tourists do on Japanese trains, according to locals
Take a trip to Japan’s Dododo Land, the most irritating place on Earth
Naruto and Converse team up for new line of shinobi sneakers[Photos]
Survey asks foreign tourists what bothered them in Japan, more than half gave same answer
Japan’s human washing machines will go on sale to general public, demos to be held in Tokyo
Starbucks Japan releases new drinkware and goods for Valentine’s Day
We deeply regret going into this tunnel on our walk in the mountains of Japan
Studio Ghibli releases Kodama forest spirits from Princess Mononoke to light up your home
Major Japanese hotel chain says reservations via overseas booking sites may not be valid
Put sesame oil in your coffee? Japanese maker says it’s the best way to start your day【Taste test】
No more using real katana for tourism activities, Japan’s National Police Agency says