Polish scientists compare five kombuchas, and the tea in each changes far more than flavor

Kombucha can taste tangy, floral, earthy, or lightly fizzy, but the tea behind it may influence more than flavor alone.

When researchers brewed kombucha under the same conditions using five types of tea, the finished drinks came out noticeably different, according to ScienceDaily.

What happened?

In work published in the journal Food Chemistry, Helena Moreira, Ewa Barg, Anna Szyjka, and other researchers at the Wrocław University of Environmental and Life Sciences and Wrocław Medical University made kombucha from black, green, white, oolong, and pu-erh teas.

To produce kombucha, sweetened tea is fermented by a SCOBY, or symbiotic culture of bacteria and yeast. Yeast first turns sugars into carbon dioxide and alcohol, and bacteria then convert those products into the organic acids that give kombucha its characteristic tartness, ScienceDaily reported.

"The type of tea acts as a specific matrix that shapes the course of fermentation and the final composition of kombucha," Moreira told the outlet.

Using advanced laboratory techniques such as chromatographic methods and mass spectrometry, the researchers followed hundreds of compounds during fermentation. In some brews, floral and fruity molecules such as linalool and 2-phenylethanol increased, while other compounds present in the fresh tea disappeared over time.

The type of tea produced noticeably different chemical profiles and flavors. Black tea and pu-erh produced deeper, earthier kombuchas; green tea versions came out fresher and more vegetal; and oolong developed stronger floral and fruity notes.

Why does it matter?

The results suggest kombucha is not a single, uniform health drink. Changing the tea base can alter the beverage's chemistry, aroma, and biological activity.

Among the kombuchas tested, the green tea and oolong versions showed the greatest antioxidant activity. These types also showed the strongest ability to neutralize free radicals, which are molecules that contribute to aging and harm cells.

This study suggests that not all kombuchas offer the same potential benefits, even if they appear similar on store shelves. 

Moreira said fermentation is drawing increasing scientific attention because it may make bioactive compounds more available and generate new metabolites. Still, the researchers cautioned that their results came from laboratory analysis, not human clinical trials.

What are people saying?

"The most surprising aspect was the scale of changes occurring during fermentation and how strongly they depended on the type of tea used," Moreira said. "... The results of our research indicate that the type of tea influences not only the taste and aroma, but also the biological activity of kombucha. Particularly interesting results were obtained for kombuchas prepared from green and oolong teas, which demonstrated the highest biological potential."

She noted that more studies are necessary to show how kombucha types impact human health.

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