I Tried Bad (Old) Sencha: What Actually Happens

The visual differences in the dry leaves were already noticeable before anything was brewed. The fresh leaves were dark green, shiny, and visually sharp. The old leaves had taken on a reddish-brownish tint and had noticeably less surface shine.

The dry aroma gap was even more striking. Fresh sencha leaves carry umami and sweetness in their scent in a way Yuki describes as one of the best smells in the world. The old leaves offered almost nothing. A faint trace of green tea notes remained if you concentrated, but any sweetness or umami was essentially gone, replaced at the edges by something Yuki described as resembling dead or autumn leaves. Not rotten, just empty.

The most important point Yuki makes is directed at anyone who tried sencha once and concluded it was not very good. A significant proportion of those experiences were probably with tea that had been sitting around improperly stored, whether in a shop on a shelf in room temperature, in a cupboard at home, or in a bag that was not resealed after opening.

Degraded sencha does not taste bad in an obvious way. It tastes weak and flat, which can easily be mistaken for the tea being low quality, or for Japanese green tea simply not being to your taste. The reality is that what was tasted had lost virtually everything that makes the tea interesting. Yuki is direct: do not judge sencha by a cup like this. The actual tea is substantially better.

The conditions that ruined this sencha were exactly the conditions described in Tealife's storage guidance: exposure to light, heat, and air. The fix is equally simple. Store sencha airtight, away from direct light and heat, ideally in a refrigerator or freezer for the bulk of the supply. Decant a week's worth into a small caddy for daily use, keeping that portion away from sunlight and heat.

Yuki also notes that Tealife stores its tea in refrigerated conditions at all times as an online shop, which preserves quality from the source. This is a structural advantage over most physical retail environments where tea sits on shelves at room temperature.

On conducting a live experiment rather than a theoretical warning: Rather than simply describing what poor storage does to sencha in abstract terms, Yuki brewed both cups side by side and tasted them in sequence. The difference in his reactions between the fresh cup (genuine enthusiasm, immediate satisfaction) and the old cup (pause, visible disappointment, description of flatness and dead leaves) is more convincing than any written description. The experiment also provides useful baseline data: it grounds the 2 to 3 percent quality estimate in an actual sensory comparison rather than speculation.

On the 2 to 3 percent estimate: One key observation is how Yuki frames the scale of degradation. He specifically rejects the idea that this is a modest decline (not 100 to 80 percent) and instead describes it as near-total collapse. This framing is useful because it challenges the assumption that improperly stored tea is just slightly inferior. It is functionally a different and much worse product.

On the experience of people who have tried and dismissed sencha: Yuki addresses a real and common problem: people forming a negative or neutral impression of sencha based on a degraded or poorly made cup. His direct message is that this experience is not representative. The implication is that storage quality, both at the retail level and at home, has a larger impact on the tea experience than most buyers realize or account for when forming their preferences.

Yes, and the degradation is severe. Exposure to heat, light, and air triggers oxidation that destroys the amino acids and aromatic compounds responsible for umami, sweetness, and fresh aroma. Yuki's comparison showed the quality dropped to approximately 2 to 3 percent of the original within what appeared to be a few months of improper storage.