There is sediment in the bottom of my cup

In short

Distinguish sediment from cloudiness first: cloudiness stays suspended and is often intended, while sediment settles and usually is not. Once separated, the causes are mostly filtration and leaf grade.

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. Fine leaf passing an open filter

   Equipment

   Check: Is the leaf broken, dusty, or from a compressed cake?

   Fix: Use a finer strainer on the way out. Leaf broken from a cake carries a great deal of fine debris, which is one reason a rinse before the first infusion is standard for compressed dark tea.

2. 2. No rinse on a compressed or dark tea

   Technique

   Check: Did you drink the first steep rather than discarding it?

   Fix: Pour boiling water over the leaf, discard immediately, then begin. The rinse removes surface dust and much of the loose material that would otherwise end up in the cup.

3. 3. Deep-steamed Japanese green tea, which is meant to be cloudy

   Leaf quality

   Check: Does it stay suspended and make the whole cup opaque, rather than settling?

   Fix: That is not sediment and not a fault. Fukamushi leaf breaks down considerably in processing, and the fine particles carry much of the body the style is chosen for.

4. 4. Matcha that has settled out

   Technique

   Check: Is it powdered tea, and did it separate within a minute?

   Fix: Poorly milled or stale powder settles fast. Sift before whisking, use a wide bowl, and drink promptly — matcha is a suspension and will always separate eventually.

5. 5. Scale flakes from the kettle

   Water chemistry

   Check: Are the particles pale and chalky rather than dark?

   Fix: That is limescale, not tea. Descale the kettle and rinse it out thoroughly afterwards.

Tea types this applies to

• Dark tea and pu-erh
• Green tea

Brewing methods this applies to

• Gongfu brewing (gaiwan) — A high-leaf, low-volume, many-infusions approach: a great deal of leaf in a small vessel, steeped for seconds at a time and poured off completely, repeatedly.
• 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.

Guides covering this

• Foam, film and the surface of the liquor — Three quite different things appear on the surface of a cup of tea — a foam, an oily film and a dull scum — and they have unrelated causes. Two are properties of the leaf and one is a property of the water.

Related problems

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

• 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 water is not the temperature the kettle says — The kettle is set to 80 °C and the tea behaves as though it were much hotter or much cooler, and the same setting gives different results on different days.
• My gaiwan is too hot to hold — The rim and lid become uncomfortable within seconds, the pour is rushed, and tea ends up on the tray.
• My first infusion is always the worst one — The opening cup is thin, dusty or flat, and the second is markedly better — consistently, across different teas.
• My pu-erh cake will not break apart cleanly — The cake resists the pick, then gives way suddenly into powder and fragments rather than intact leaf.

Sources