Drinks can "glow"
Published on 17 November 2022

What do you usually like to drink to give yourself a boost? Coffee, tea, or energy drinks? Some drinks may look ordinary but they can give off a unique glow that adds character when exposed to ultraviolet light. What is the secret behind their "glow"?

Tonic water and energy drinks containing vitamin B2 are some of the beverages available on the market that can "glow". Tonic water contains quinine, while some energy drinks contain riboflavin (also known as vitamin B2). When the electrons of quinine and riboflavin absorb ultraviolet light, they become excited, jumped to higher energy levels and remained in an unstable state of excitation. When they return to their ground state, energy is released in the form of fluorescence. In this process, quinine glows blue and riboflavin glows yellowish green. Speaking of quinine, it is a drug used to treat and prevent malaria. Tonic water contains low doses of quinine, which gives the drink a slightly bitter taste.

I like to have a cup of espresso to refresh myself. Recently, I love to drink espresso tonic. Tonic water goes well with the acidity and slight bitterness of coffee, giving it a rich flavour. Let's give it a try in making an espresso tonic, a special drink with distinct layers and fluorescent effect!