Kyusu Teapot Care: Cleaning, Strainers, and Tea Stains

A kyusu needs a clean strainer, no leftover leaves and enough time to dry. Cleaning instructions vary with its body, finish and fittings. A drop of detergent does not automatically ruin every Tokoname pot, and “never wash any kyusu with soap” is not a reliable rule.

This guide covers everyday rinsing, clogged strainers and tea stains, with separate attention to unglazed clay and glazed porcelain. Use the maker’s instructions for the individual pot.

Identify what kyusu you have

Common examples include unglazed clay and glazed porcelain. Both vary in finish and construction.

Unglazed clay kyusu include Tokoname-yaki (常滑焼) shudei (朱泥, red clay) from Aichi and Banko-yaki (萬古焼) shidei (紫泥, purple clay) from Mie. Their colour and surface can change with use, but a brown deposit is not proof of improved brewing or a required seasoning layer.

Glazed porcelain kyusu include Arita and Hasami examples. Their smooth interiors are often straightforward to clean, but spouts, strainers and decorations still need appropriate care.

Confirm the body and finish from the product description. Gloss alone cannot distinguish porcelain from polished clay or a glazed pottery body; do not scratch the surface to test it.

(Cast iron lined kyusu — tetsu kyusu — are covered in our cast iron tetsubin care guide.)

First use

Read the new pot’s care card before use. A general preparation checklist is:

1. Inspect the body, lid, spout and strainer for damage.
2. Rinse or wash as the maker directs to remove loose dust.
3. Use the water temperature approved for the pot. Choose brewing temperature separately according to the tea; unglazed clay does not create a universal ban on freshly boiled water.
4. If the maker prescribes a first-use treatment, follow that method.
5. Do not assume every kyusu needs two discarded pots of tea to become usable.
6. Rinse with warm water and air-dry fully with the lid off.

After the prescribed preparation, the pot is ready to brew. Persistent unusual taste or odour needs investigation rather than repeated attempts to “season it away”.

Daily care — washing

For daily care, begin with the maker’s washing instructions.

Tokoname’s official care guide recommends water without detergent for routine cleaning to avoid lingering smells.

That advice is not proof that one drop of soap permanently destroys a pot. For glazed porcelain or a particular clay model, use the manufacturer’s cleaning guidance and rinse any permitted cleaner thoroughly.

Daily routine:

1. Immediately after pouring the last cup, open the lid and discard the used tea leaves. Do not leave them sitting in the pot — they continue to oxidize and impart a stale flavor to the next brew.
2. Rinse with water as directed and avoid abrupt temperature changes. Keep fingers clear of hot water.
3. Remove residue gently using tools suitable for the finish.
4. Rinse the strainer carefully — see the next section.
5. Dry with the lid removed and the pot supported securely so water can drain. Drying time depends on shape, airflow and humidity; check that the interior and strainer are dry before storage.

Loosen lodged leaves gently with water. If rinsing does not clear the strainer, use the method appropriate to its construction below.

The strainer

Three strainer types appear in modern Japanese kyusu, each with slightly different maintenance:

Ceramic strainers include holes formed in the body and separately made perforated filters. Sasame (ささめ) describes a fine ceramic strainer, not one universal casting method.

• Rinse from the inside of the pot outward (pour warm water through from the body toward the spout).
• For clogging, the official Tokoname guide describes gentle toothbrush cleaning when the inside is dry. Use light pressure and follow the instructions for your filter.
• Do not force pins or wire through small ceramic holes. If gentle cleaning fails, ask the maker.

Removable stainless steel mesh basket — common in modern porcelain and some Banko kyusu. Lift out the mesh. Rinse under warm water. A soft brush is fine if needed. Replace dry.

Obi-ami (帯網) band mesh — a fine stainless mesh band fitted around the inside spout opening. Rinse with the pot upright and the spout pointed down. Avoid poking the mesh.

Inspect the filter as part of regular cleaning. Clear remaining leaf fragments before they dry into a blockage.

Avoid metal scourers and forceful poking. Damaged ceramic filters or bent mesh need assessment rather than aggressive reshaping.

Tea stains: cleanliness before a patina rule

Cha-shibu (茶渋) refers to tea staining. It can occur in glazed and unglazed pots. Its presence does not establish quality or make cleaning undesirable.

Do not leave accumulated residue merely to “raise” the pot. The maker’s cleaning guidance takes priority over claims that a dark interior must improve future tea.

If stains persist, check the recommended cleaner for the body and fittings. A smooth porcelain interior and a fitted metal filter may require different handling.

Ukō kiln gives a stain-removal procedure for its kyusu, followed by thorough rinsing, and allows gentle toothbrush cleaning of mesh. Do not apply its chemical treatment to an unidentified pot or improvise the concentration.

Avoid guessed baking-soda, bleach or tea-leaf treatments. Where a maker permits a cleaner, follow both the product instructions and the cleaner’s label; never mix cleaning agents.

Does each tea need its own pot?

A separate pot for strongly aromatic tea is a preference rather than a universal Japanese rule.

• Ukō kiln says its strainers work with different Japanese teas, while noting that some people notice lingering aromas when returning to delicate tea.
• The effect depends on the pot’s finish, its cleanliness and the drinker’s sensitivity.

If roasted or scented tea leaves a distracting aroma, a separate pot may suit you. Buying a second pot is not a requirement for brewing another tea.

A clean glazed porcelain pot is a useful option when frequently switching teas. Keep its strainer and spout clean too.

What never to do

• Do not use a cleaner that the maker prohibits. If detergent was used by mistake, rinse thoroughly and seek advice if an odour remains; do not assume the pot is irretrievably ruined.
• Use a dishwasher only if the complete pot, decoration and fittings are approved for it. Otherwise hand-wash.
• Do not microwave a kyusu unless the exact configuration is approved. Metal fittings and fragile or decorated parts require particular attention.
• Avoid thermal shock. Water temperature should suit both the vessel’s instructions and the tea recipe.
• Never poke the strainer mesh with toothpicks, wires, or pins. Once chipped, the pour pattern is permanently affected.
• Remove used leaves after brewing; do not put the pot away with wet leaves inside.
• Dry before closing for storage. A closed lid can trap residual moisture.

Storage

After daily use:

• Dry the pot and lid fully with ventilation. There is no single hour count that proves every interior is dry.
• Store the body and lid together in a ventilated cabinet with the lid placed askew on top, allowing air circulation inside.
• For unglazed clay kyusu, avoid sealed plastic containers — they trap residual moisture and promote interior mold.

For seasonal or rarely-used kyusu:

• Clean and dry thoroughly before protective wrapping and boxing. Avoid pressure on the handle, spout or lid.
• Before using a long-stored pot, inspect and rinse or wash as directed. Do not assume the clay needs a special rehydration treatment.

FAQ

Can I use soap to wash my kyusu?

Follow the maker’s instructions. Routine water rinsing is recommended for many Tokoname pots to avoid smells, but a blanket soap ban for every glazed and unglazed kyusu is inaccurate. If a permitted cleaner is used, rinse thoroughly.

Can I use the same kyusu for sencha and hojicha?

Often yes. A separate pot may help if you notice lingering roasted aromas, but one pot per tea is a preference, not a universal requirement. Cleaning and the interior finish matter.

Should I clean off the brown stain inside my kyusu?

Do not preserve tea residue as a compulsory seasoning layer. Follow the maker’s method for cleaning stains and keeping the filter clear.

Can I put my kyusu in the dishwasher?

Only if the exact pot and its fittings are approved. Otherwise wash by hand; material or regional name alone does not establish compatibility.

Why does my new Tokoname kyusu taste of clay?

Rinse or prepare a new pot as directed. A persistent unusual taste cannot be diagnosed as harmless clay dust from a general article; contact the maker rather than relying on a guaranteed two-brew cure.

How is kyusu care different from cast iron tetsubin care?

A tetsubin boils water; a kyusu brews tea. Their internal surfaces and cleaning needs differ. See our cast iron tetsubin care guide for maker-specific preparation and drying; do not transfer kettle rust treatments to a ceramic teapot.

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Editor’s note: The product record should identify the individual kyusu’s material, origin and care. This general guide does not establish a workshop relationship or a particular item’s appliance compatibility.