• Episode 39 | Food Inflation and Tea

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Interfacial surface film that forms on black tea.
Interfacial surface film that forms on black tea.

The Physics of Black Tea Film

By Dan Bolton
Have you ever noticed a colorful sheen on the surface of your tea? It appears brittle, breaking like ice floes in the arctic as the tea cools. Researchers once thought it formed from waxy substances in leaves released during steeping. That is not the case. The delicate film is an interfacial interaction of air, tea polyphenols, and calcium carbonate ions in water. It does not form on white, yellow, green, or lightly processed oolong teas, only black tea. In many parts of the world soft water prevents the film from forming. Is tea film a fleeting glimmer of color to enjoy or an unsightly scum that dissipates with a squeeze of lemon? Or does it? Caroline Giacomin, a student at ETH Zürich, in Switzerland joins us to explain the physics of tea film from a study she and colleague Peter Fischer recently published in the Physics of Fluids. Read more…

Listen to the interview

Caroline Giacomin on the physics of black tea film

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Markets today are volatile and confusing – more so due to the pandemic and changing consumer behavior. The best way to respond locally is to keep the big picture in mind. Knowing the underlying trends behind the daily headlines helps tea professionals better interpret the news of the day. This overview is one in a series of 15-minute talks on the business of tea. – Dan Bolton

Click below to view the presentation in Spanish:
Dia Internacional del Te Detras de los Titulares


Tea Biz offers insight in real-time for beverage professionals scanning daily news items about their trade.

Tea is both art and craft. It nourishes and inspires. It is the most ancient of plant-based medicines, simultaneously energizing the body as it soothes the mind. Intimately local in character, the tea trade exerts global influence, employing millions to supply consumers at far greater volumes than coffee.

It is a fascinating, intricate topic… far more complex than one person can master. That is why the Tea Biz Podcast enlists 40 voices skilled in 12 languages to tell the story of tea: authentic reporting relies on the expertise of tea professionals who know the tea lands from birth and speak the native tongue.

Transparency is storytelling grounded at origin.


QTrade Teas & Herbs understands that a successful tea blend goes beyond the creative fusion of appearance, aroma, and flavor.
Our multi-award-winning product-development team is passionate about converting natural ingredients into sensory experiences that customers crave. Every recipe is formulated with a commercial backbone of dependable, quality sourcing with a pricing structure that supports a safe, regulated, profitable, and scalable blend.
QTrade meets every brand’s retail, food service, and E-Commerce needs.
Visit www.qtradeteas.com

Tea Biz TEAm

Aravinda Anantharaman

“What came first, the tea or the story? For every tea I drink, there seems to be a story in the wings, waiting for a listener. Tea and stories, can’t have one without the other! I am in search of both.” 

Jessica Woollard

“The world of tea has endless stories. Stories of history, culture, business, agriculture and tradition. I feel so lucky to be able to tell some of them.”

Kyle Whittington

Kyle Whittington

“Tea draws us in. The tea itself, teapots, ceramics, and the stories behind the tea’s own books. I can’t resist picking up yet another book on tea and adding it to my tea bookshelf. Can you?”

Dan Bolton

“Tea is proven to enhance the well-being of those who drink several cups a day. It inspires a process of discovery among imbibers, cultivating a deep appreciation for the growing, crafting, and preparation of great tasting tea. Finding your own favorite tea leads to a daily ritual and, in time, a healthy life-long habit.”

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