Why ware changes the cup
Dark tea is post fermented and usually compressed, and both facts point the same direction on ware. It needs sustained heat, and it needs volume.
Compressed leaf takes several steeps to open fully. A vessel that holds heat helps it along, and one that cools quickly will cost you the first two or three pours.
The second factor is the dose. Dark tea is brewed strong and long, and 8 grams in 200 millilitres is normal, roughly double a green tea dose.
The third is that much dark tea is boiled rather than steeped, which rules out delicate ware and calls for something that will take direct heat.
A fourth point is that dark tea is tolerant of water quality in a way delicate teas are not, but it still answers to ware. Two identical doses in different pots do not taste the same.
It is also the category where the same vessel gets used for a decade. That is worth weighing when you choose, because the seasoning you build is not reversible.
Best ware for Dark tea
A 200 millilitre Yixing or ceramic pot is the standard tool. Eight grams, a full boil, a ten second rinse first, then 20 second steeps.
An insulated flask is genuinely good for dark tea, which is unusual. Five grams in 500 millilitres of boiling water left for an hour gives a thick sweet liquor.
A glass or ceramic kettle suits aged material. Five grams in 600 millilitres, simmered for 10 minutes, and top up as the level drops.
A gaiwan works for ripe pu-erh when you want to taste it carefully, though it is hard work. The leaf is fine and dark and it clogs the lid.
If you buy one thing, buy a small ceramic pot you can also sit on a warmer. Dark tea is the one category that rewards keeping the vessel hot between steeps.
For ripe pu-erh specifically, a 150 to 200 millilitre pot is the sweet spot. It is large enough for the dose and small enough to keep the ratio right across ten steeps.
A small electric warmer under a glass kettle is the cheapest way to make good aged dark tea at home. Keep it at a bare simmer rather than a rolling boil.
What to avoid
Avoid small basket infusers. Compressed leaf expands several times over, and a small basket strangles it, which is the most common reason a pu-erh tastes flat.
Avoid glass for a long session. Dark tea is often steeped ten times or more, and glass loses too much heat between pours.
Avoid using the same clay pot for dark tea and anything delicate. The seasoning is permanent, and it will dominate a green or white tea completely.
Avoid thin walled cups for serving. Thick walled small cups hold the aroma better and keep the liquor warm through a long session.
Avoid a porcelain gaiwan for raw pu-erh if you are new to the category. The heat loss makes early steeps thin and later ones harsh, which is a confusing first impression.
Avoid leaving wet leaf sealed in a pot overnight. Post fermented tea moulds faster than any other category, and a sealed damp pot is exactly the wrong place for it.
The one rule
Keep the heat in. Dark tea is the only category where retaining temperature for as long as possible is nearly always the right call.
When the tea tastes thin and earthy without sweetness, it probably never got hot enough or you used too little leaf. Fix the dose first.
When it tastes muddy, you skipped the rinse or you are using water too hard for a compressed tea.
Dark tea is the most equipment friendly category in practice. A thermos and a chunk of cake will beat what most people get from a full set of ware.
One test: brew 8 grams in 200 millilitres in thin porcelain and again in clay. The clay version will usually taste thicker and less sharp from identical leaf.
Because dark tea is bought as a cake, the useful ware also includes a prying tool and a scale. A wide tray to break leaf on helps more than another pot does.