My teapot came out of the dishwasher damaged or tasting wrong

In short

A dishwasher combines three things teaware handles badly: strongly alkaline detergent, sustained high temperature, and a long wet cycle followed by heated drying. Glazed porcelain without decoration generally survives all three; almost every other kind of teaware fails on at least one, and two of the failures cannot be undone. The useful move is one rule per material rather than one rule for the cupboard.

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 unglazed clay, and detergent has entered the body of the pot

   Equipment

   Check: Is it a yixing, a Chaozhou pot, a Tokoname kyusu or any other unglazed vessel — matte rather than shiny, and slightly porous to the touch?

   Fix: Do not put unglazed clay in a dishwasher, and do not use detergent on it by hand either. The porosity that makes these pots desirable is exactly what absorbs detergent, and it is held in the body rather than sitting on the surface, so rinsing reaches only part of it. Hot water and a soft brush are the whole cleaning routine. Where it has already happened, repeated hot-water rinses and several sacrificial brews reduce it over weeks, and some pots never fully clear.

2. 2. The decoration is on top of the glaze rather than under it

   Equipment

   Check: Run a fingernail across the pattern or the gold rim. Can you feel it standing proud of the surface?

   Fix: Overglaze enamel, gilding and lustre sit on the glaze and are removed by alkaline detergent and heat over repeated cycles — the pattern goes matte, then patchy, then gone. Wash these by hand. Underglaze decoration, which is sealed beneath the glaze and feels perfectly smooth, is not at risk.

3. 3. Thermal shock has crazed the glaze

   Equipment

   Check: Hold it to the light. Is there a fine network of hairline cracks in the glaze that was not there before, particularly where the handle joins?

   Fix: Crazing is the glaze cracking because it and the body expanded at different rates, and a dishwasher's heated cycle is a common trigger on thinner or older pieces. It is not repairable. Crazed vessels also hold tea in the cracks and stain and smell more readily afterwards, so a crazed pot is better retired to a shelf than kept in rotation.

4. 4. Detergent residue is in a part that never rinses

   Equipment

   Check: Is the taste soapy or perfumed rather than the object being visibly changed — and is this a travel infuser, a flask, or a pot with a silicone seal?

   Fix: Take the lid apart. Silicone gaskets lift out, hold detergent underneath, and almost nobody removes them. Wash the parts separately, rinse each far longer than feels necessary, and dry them open before reassembling. The separate record on soapy-tasting tea covers the non-dishwasher versions of this.

5. 5. It is plain glazed porcelain or borosilicate glass, and nothing is wrong

   Equipment

   Check: Is it undecorated glazed porcelain, bone china without a metal rim, or borosilicate glass — and is the only complaint that it looks cloudy?

   Fix: These tolerate a dishwasher. Cloudiness on glass in a hard-water area is mineral film from the water rather than damage, and a rinse aid or a wipe with dilute citric acid clears it. This is the one branch where the honest answer is that the worry is unfounded.

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.
• 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.

When this cannot be fixed

Two of these do not reverse. Overglaze decoration that has been etched away is gone, and a crazed glaze cannot be re-fused. Unglazed clay that has absorbed detergent sits in between — it improves with rinsing and use rather than being restored, and how far it comes back is not predictable from the outside.

Related problems

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

• 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 tea goes cold before I finish it — The cup is lukewarm within a few minutes, and in a gongfu session the later infusions arrive noticeably cooler than the early ones.
• There are black spots inside my teapot or infuser — Dark speckling inside a spout, under a lid seal, in the mesh of an infuser or around the gasket of a travel bottle.
• My tea tastes of chlorine, metal or the kettle — A chemical, swimming-pool or metallic note sits over the tea, and it is there whichever tea is brewed.
• My white tea tastes of almost nothing — The cup is pale and barely flavoured, and it stays that way whatever is adjusted.

Sources