Fermented foods have had a moment for a while now: kimchi, kombucha, kefir, miso, all things that used to be regional specialties and are now fairly mainstream. That interest has started reaching tea too, and Afterglow, our kurokoji-fermented tea, sits right at that intersection.

What fermentation actually is, briefly

Fermentation means introducing a living microorganism, in Afterglow's case kurokoji, or black koji, and letting it actively transform the leaf over time, rather than just letting the leaf's own enzymes oxidize on their own the way black tea works. It's the same basic process behind miso and shochu, just applied to tea instead of soybeans or rice. That's a meaningfully different thing happening to the leaf than steaming or roasting, and it's part of why fermented tea tastes so different from anything else in our lineup.

Why people are drawn to fermented foods generally

A lot of the current interest in fermented foods comes from general curiosity about traditional preservation and flavor-building techniques that predate modern food processing. Fermentation was originally a practical solution: a way to preserve food and develop flavor before refrigeration existed. That history is part of the appeal, a food or drink shaped by a living process rather than a factory one.

What we can honestly say about Afterglow

We're careful here, because we're not doctors and we don't want to overstate anything about what a cup of tea can or can't do for you. What we can say is that fermentation changes the tea meaningfully, deep, earthy, a little sweet, genuinely unlike a straight green or black tea, and that if you're already someone who enjoys other fermented foods for their flavor and tradition, that same curiosity is worth bringing to tea.

That said, early research on microbially fermented tea has been conducted in small clinical studies. Researchers tracked at metabolic markers in around three dozen people and found meaningfully lower triglyceride levels after 12 weeks of drinking microbially fermented tea, along with a better insulin response during a glucose tolerance test.

How to try it

Whisk it into hot water the way you would any of our teas, or work it into a smoothie or baking if you want to explore it as an ingredient rather than a drink on its own. Either way, it's worth trying simply because it's a genuinely different tea experience, not because of a promised health outcome.