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: 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 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.

Ever wondered why some matcha is smooth and mellow while others taste bitter, earthy, or just plain flat? Turns out, it’s not just your imagination—and it’s definitely not all about price or the word “ceremonial” on the label. Real scientific research looked at 11 matcha samples from Japan and China, breaking down exactly what makes one matcha smoother, greener, and more enjoyable than another. This study (link at the end of the article) dove deep into taste compounds, color chemistry, and even flavor molecules. Let’s break it all down in a way that’s easy (and fun!) to understand-so the next time you sip matcha, you’ll know exactly what to look for. The Greener, the Better? (Usually, Yes.) That signature vivid green color you see in high-grade matcha? That’s chlorophyll at work-a natural pigment that also plays a role in taste and freshness. The more chlorophyll, the fresher and more vibrant your matcha looks-and often tastes. Japanese matcha from regions like Shizuoka came out on top for chlorophyll levels. Certain Chinese matcha from Guizhou and Zhejiang also scored high here. These samples had total chlorophyll levels well above 12 mg/g—very solid numbers. On the flip side, some samples from Jiangsu and Zhejiang showed chlorophyll levels as low as 9–10 mg/g, which may explain their duller green hue. A key bonus: better chlorophyll isn’t just prettier—it’s linked to better cultivation practices, like proper shading before harvest. Umami vs. Bitterness — It’s All About Chemistry Matcha flavor comes down to a tug-of-war between two major compounds: Ideally, you want a matcha with lots of L-theanine and not too many polyphenols. That’s what gives it a round, mellow, savory flavor without the bite. In this study, Japanese matcha hit the highest L-theanine levels—up to 28.5 mg/g. The smoothest samples also had low RTA scores (polyphenol-to-amino acid ratio), a marker of taste balance. Lower RTA = better. But here’s where it gets cool: matcha from Guizhou and Shandong in China also had pretty impressive numbers. Some Chinese teas nearly matched Japanese levels of theanine and RTA. Others… not so much, with theanine dipping as low as 9.3 mg/g—resulting in sharper, less rounded flavors. Moral of the story? The numbers don’t lie—your taste buds aren’t imagining it. What About Caffeine? While matcha is often celebrated for its calming L-theanine, it still packs a caffeine punch—and this study measured that too. Most Japanese matcha samples had caffeine content above 4%, with one reaching 4.41%, the highest in the study. Chinese matcha showed more variety: Guizhou samples had caffeine levels close to Japan, while Zhejiang and Shandong samples came in lower—between 1.72% and 3.9%. If you’re looking for that alert-but-calm balance, matcha with both high L-theanine and caffeine (like Shizuoka or Guizhou matcha) may be your best bet. And RTA? That’s Your Flavor Balance Key RTA stands for Ratio of Tea Polyphenols to Free Amino Acids. It’s basically the scientific way to measure how bitter a matcha is compared to how savory and smooth it tastes. In this study, RTA values ranged from 3.46 (very smooth) to 13.85 (quite bitter). All Japanese samples scored under 7, showing consistent balance. A few Chinese matcha samples matched that profile, but others with higher RTA (especially above 10) had noticeably more astringency and less umami. In short: if the label ever shares RTA, lower is usually better for an everyday, pleasant cup. Why Does Matcha Smell Like the Ocean (In a Good Way)? Aroma is a big part of the matcha experience, and this study went beyond basic sniff tests. Scientists identified over 500 aroma compounds using high-tech methods. These included: Japanese matcha generally had the most well-rounded and pleasant aromas. But again, matcha from Guizhou and Guangxi in China really held their own here, especially with fruity and sweet-green notes that closely resembled high-end Japanese teas. Meanwhile, samples with more aldehydes tended to have sharper, more pungent aromas—not necessarily bad, but a different experience. If you’ve ever had a matcha that smelled fresh and clean versus one that felt earthy or flat, these compounds are what you were picking up. What’s the Takeaway for Everyday Matcha Fans? If you love matcha—or are just getting into it—here’s what matters: And remember: the country doesn’t guarantee quality. This study showed that some Chinese matcha came incredibly close to Japanese levels—or even surpassed them in specific areas like aroma or antioxidants. Want to Choose Smarter (and Sip Happier)? Start by checking where your matcha comes from. Regions like Shizuoka (Japan), Guizhou (China), and Guangxi (China) consistently delivered excellent color, flavor, and smell. Look for brands that show lab testing and are transparent about sourcing. Want to go deeper? Some companies (like us 👀) share this kind of data directly—so you’re not just buying hype, you’re buying quality. Learn more about matcha, the right way — at thess-matcha.com Based on: Luo et al., 2023, Frontiers in Nutrition. https://doi.org/10.3389/fnut.2023.1153983