Why matcha creates a rich foam, but green tea doesn’t?
One of the most iconic parts of preparing matcha is the creamy green foam that rises to the surface as you whisk. From the Japanese tea ceremony to modern matcha lattes, this frothy layer signals quality and tradition. But why does matcha foam so well, while a regular cup of green tea doesn’t foam at all?
What Is Foam?
In simple terms, foam is just air bubbles trapped in liquid. When you whisk or pour a drink, air enters and forms bubbles. But for those bubbles to last, the liquid needs certain natural stabilizers — molecules that surround the air pockets and keep them from popping.
That’s why whisking matcha creates a silky layer of froth, while stirring plain water does not.
Why Matcha Foams So Well
The secret lies in how matcha is made. Unlike green tea, which is brewed by steeping leaves, matcha is stone-ground powder. When you whisk matcha, you suspend the entire tea leaf in water. This means your cup contains all the natural foam-building compounds that don’t usually dissolve in a simple infusion.
Studies on matcha foam science show that:
- Catechins (especially EGCG) – increase foaming power.
- Amino acids (valine, asparagine, threonine) – stabilize bubbles.
- Proteins & pectins – form a network around the foam.
- pH around 6.0 – creates balance for stable froth.
Together, these compounds act like a “molecular whisk,” trapping air and giving matcha its signature creamy foam.
Why Green Tea Doesn’t Foam
So what happens with regular green tea?
When you steep green tea leaves, only the soluble compounds dissolve into the water. Most of the important foam stabilizers — proteins, pectins, and certain amino acids — stay locked inside the leaf. Without them, any bubbles that appear on the surface pop almost instantly.
That’s why green tea may show a thin layer of bubbles when poured, but it will never develop the dense, velvety matcha foam you see in a chawan.
Tradition meets hemistry
Foam has been part of tea culture for centuries. In the Song Dynasty (China), whisked tea was judged by the quality of its froth. Japanese tea ceremonies adopted the same principle: fine, bright foam means high-quality matcha and skilled preparation.
Modern research confirms what tea masters already knew — matcha’s natural chemistry makes it a unique foaming tea, unlike any infusion.
Key Takeaways
- Foam = air + stabilizing compounds
- Matcha = whole leaf in your cup → full of stabilizers → creamy foam
- Green tea = infusion only → missing stabilizers → no foam
So the next time you whisk your bowl and see that layer of froth, remember: you’re not just making tea. You’re experiencing a tradition backed by centuries of culture — and proven by modern food science.
About Thess Matcha
At Thess Matcha, we go beyond the cup. Our work focuses on research, development, and quality control of tea powders, with a special emphasis on matcha. Alongside scientific exploration, we also organize workshops and tastings to share authentic matcha culture with the community in Greece and beyond.
Written by Athanasios Gerasopoulos (Chemist BSc., MSc.), founder of Thess Matcha.
