My Japanese green tea tastes of seaweed or fish

In short

The marine descriptor is genuine and intended in steamed Japanese green tea, and it is also what a stale one smells of. The two are distinguishable, and the distinguishing feature is whether the note is sweet and clean underneath or sits on its own with nothing behind it.

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. It is correct, and it is what steaming produces

   Leaf quality

   Check: Is the marine note accompanied by sweetness and a savoury depth, and does it read as fresh seaweed or sea air rather than as fish?

   Fix: Sea air, sweet seaweed and steamed greens are the published descriptors for this whole family, and the more shaded the tea the more savoury it gets. Nothing is wrong. If you dislike it, the categories to move to are pan-fired Chinese green tea or Japanese kamairicha, which carries no marine note at all.

2. 2. Deep steaming has pushed it further than you expected

   Leaf quality

   Check: Is the liquor cloudy and deep green with sediment, and is there fine broken material in the packet?

   Fix: A fukamushi tea is heavier and more savoury with much less aroma to balance it, which reads as more marine. Brew it shorter and cooler than the sencha you are used to — deep-steamed leaf extracts much faster because it is broken.

3. 3. It is stale, and staling turns marine into fishy

   Storage

   Check: How old is the packet, has it been open a while, and is the note thin and one-dimensional with no sweetness under it?

   Fix: Green tea fades in aroma and sweetness first while the savoury and astringent parts persist, which strips out everything that made the marine note pleasant. Smell the dry leaf: clean and sweet means fresh, flatly fishy means gone. No brewing adjustment recovers it.

4. 4. Water too hot, which coarsens the savoury character

   Temperature

   Check: Are you brewing near boiling because that is what you do for other teas?

   Fix: Drop to 70 °C for sencha and considerably lower for gyokuro. Hot water on shaded Japanese tea produces a heavy, coarse, marine-forward cup and buries the sweetness that is meant to sit alongside it.

5. 5. It has taken on a smell from where it was stored

   Storage

   Check: Has it been kept near fish, a fridge, a spice shelf or a bin?

   Fix: Dry tea is an effective absorber of ambient aroma — that property is what makes jasmine scenting work. A fishy note that appeared after a move to a new container or cupboard is usually the container or the cupboard.

Tea types this applies to

• Green tea

Brewing methods this applies to

• Kyusu brewing (Japanese style) — The Japanese domestic approach to green tea: a moderate quantity of leaf, water well off the boil, short steeps, and two or three infusions from the same leaf with the times adjusted each time.
• Western brewing (teapot or mug) — A small amount of leaf in a large volume of water, steeped once for a few minutes and then strained off. The approach most English-speaking drinkers already know, and the one most teas sold in the West are made for.
• Whisking (bowl-prepared powdered tea) — Powdered leaf suspended in water rather than steeped and strained — the only common preparation in which the leaf itself is consumed rather than discarded.

Related problems

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

• 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 matcha is harsh and I think it is a cooking grade — A matcha bought to drink is dull-coloured, gritty and aggressively bitter, and the tin says culinary, cooking or ingredient grade — or says nothing at all.
• 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.
• My green tea tastes flat and looks dark in this house — A delicate green tea that tasted bright elsewhere comes out dull and heavy here, with a darker, browner liquor than it should have and none of its aroma.
• My Japanese green tea comes out cloudy — The liquor is opaque and deep green rather than clear, with fine particles suspended through it and a layer settling in the bottom of the cup.

Sources