My vacuum-packed tea faded quickly once I opened it

In short

Commercial packing excludes oxygen, either by pulling a vacuum or by flushing the packet with an inert gas. Both work extremely well and neither can be re-created at home, so opening the packet is a much larger event than it looks: it ends the preservation method rather than interrupting it. The date on the packet was set for the sealed state and stops describing the tea the moment the seal is broken.

Likely causes, in order

Most likely first. Answer the question under each one before moving on — several of these look alike in the cup and are told apart only by what was done to the leaf.

1. 1. Opening ended the packing method, and resealing does not restore it

   Storage

   Check: Was this tea sold vacuum-packed or gas-flushed, and are you judging it against the date printed on the packet?

   Fix: Judge it from the day you opened it instead. A domestic clip, fold or zip seal keeps dust out and slows air exchange; it does not exclude oxygen, which is the thing the packing was doing. Green tea and matcha are where this shows fastest and most brutally, because they were the categories the expensive packing was protecting.

2. 2. It was one large sealed unit, so opening it exposed all of it at once

   Storage

   Check: Was it a single large vacuum block rather than several small packets, and is it still in the original packaging?

   Fix: Break it down on the day you open it. Decant into several small airtight containers, fill each as full as it will go so there is little headspace, and open only one. A vacuum block's whole advantage was that none of it was exposed; once opened, the only lever left is how much of it is exposed at a time.

3. 3. A puffed packet is usually the packing working, not failing

   StorageInferred by TeaHQ, not established

   Check: Did the packet arrive inflated and firm rather than shrink-wrapped tight, and does the tea inside smell and taste normal?

   Fix: Gas flushing deliberately leaves a packet full of inert gas rather than evacuated, so a taut pillow is the intended shape for that method. Air freight and altitude also expand a sealed packet on the way. Neither is a defect. What would be a concern is a packet that has gone soft and slack from tight, which suggests the seal has failed — check that one by smell.

4. 4. The original pouch is a better container than what it was moved into

   Storage

   Check: Was the tea decanted into a glass jar, a display tin or a ceramic caddy because it looked better?

   Fix: Keep it in the foil laminate it came in and put that inside the attractive container. Foil laminate blocks light and water vapour; glass passes light, and most decorative tins and caddies do not seal at all. The pouch was engineered for this and the jar was engineered for a shelf.

Tea types this applies to

• Green tea

Related problems

Sharing a cause category, a tea type or a brewing method with this one.

• My tea goes damp within weeks and I live somewhere humid — Leaf that arrived loose and crisp becomes soft, slightly clumped and quiet within a few weeks, and the aroma flattens long before any best-before date is close.
• My matcha powder has gone dull green or khaki — The powder that was vivid green when the tin was opened is now olive, khaki or faintly brown, and the bowl looks muddy rather than bright.
• My refrigerated tea has gone damp and lost its aroma — Tea kept cold has become soft or slightly clumped, smells muted, and tastes flat and papery within weeks of being put away to protect it.
• My tea tastes of the cupboard it was kept in — The dry leaf carries a note that does not belong to it — spice, coffee, cleaning products, or simply a generalised kitchen smell — and the same note comes through in the cup.
• I bought a big bag to save money and it was stale before I finished it — A large quantity bought at a good unit price faded well before it was drunk, so the saving turned into waste.

Sources