The decisions nobody argues about
Clay against porcelain against glass occupies most of the discussion of teaware, and for a great many drinkers it is the least consequential of the choices in front of them. Whether the leaf has room to open, how quickly the vessel drains, and whether it can be emptied completely will change a cup more than the material it is made of — and unlike material, all three can be assessed by looking at and handling the object rather than by trusting a claim made about it. That asymmetry is probably why they are discussed so little: material invites connoisseurship and argument, while geometry invites a two-second check that settles the matter. What follows is the short list worth running through before buying anything, in roughly the order the items matter. Applied honestly it will rule out a good deal of attractive teaware, and it will also rescue some very ordinary-looking objects that turn out to brew extremely well.
Expansion room, and how much is really needed
Dry leaf expands to several times its volume when it wets, and rolled oolong and compressed tea expand a great deal more than that — a gaiwan a fifth full of tightly rolled pellets can be packed solid by the third infusion. A jammed leaf bed is not extracting from its interior at all, because water takes the path of least resistance around the outside of the mass rather than through it. This is the mechanism behind the persistent complaint that loose leaf tea is weak: it is very often not under-dosed but under-wetted, and adding more leaf makes it worse rather than better. The practical check is to look at the vessel with the intended dose in it and ask whether the leaf could treble in volume without touching the lid. A narrow ball infuser fails that test at almost any dose, which is precisely why it produces disappointing tea from good leaf and why it is the single most common piece of bad equipment in domestic use.
The filter is a rate limiter
Whatever holds the leaf back also decides how fast the vessel empties, and drain time is steep time. A fine mesh designed for deep-steamed Japanese leaf will clog on fines from a broken tea and turn an intended fifteen-second steep into a fifty-second one, silently. A coarse three-hole spout on a gaiwan drains in a couple of seconds and lets fragments through into the cup. Neither is better in the abstract, and matching the filter to the leaf grade actually being brewed is the decision that matters — a single vessel cannot do both jobs well. The diagnostic sign that the filter is the problem is a pour that starts fast and then stalls, which means the leaf bed has packed against the mesh under the pressure of the pour. The fix in that case is a filter with more area rather than one with finer holes, which is the opposite of what the symptom suggests.
Drain time is steep time, and it is not small
A vessel that takes fifteen or twenty seconds to empty has added that long to every infusion, at falling temperature, and in a style built on ten-second steeps that is a doubling rather than a rounding error. It also extracts unevenly while it does so: the last of the liquid to leave has been in contact substantially longer than the first, and has been passing through an increasingly concentrated leaf bed on the way out. That is one of the reasons the end of a pour is stronger than the beginning, and it is a reason quite separate from the concentration gradient in the vessel. Fast, complete drainage is the single most useful mechanical property a brewing vessel can have, and it is why the gaiwan — an object with no filter to speak of, a lid pressed into service as one, and a shape that is awkward to hold — remains the standard tool for short-steep brewing after everything else has been tried.
Spouts, lips and the last drops
Every vessel retains something after pouring, and whatever it retains carries on extracting between infusions at whatever temperature the vessel is holding, then joins the next steep already over-extracted. Shapes that trap liquid retain more: a deep sump below the level of the spout, a wide flat base that the pour cannot reach the far side of, a filter basket that sits down in the liquid rather than above it. Shapes that pour cleanly to nothing retain very little. Checking this before buying is trivial — fill with water, pour out as completely as you can, and look at what is left — and vessels that look almost identical differ enormously on it. The amount left behind is not a cosmetic matter: it is the mechanism behind the flattened session arc described elsewhere in this catalogue, and it is entirely determined by the shape of the object.
Shape, and how the leaf bed sits
A tall narrow vessel makes a deep leaf bed that water has to pass through; a wide shallow one makes a thin bed that water largely sits above. The deep bed extracts more evenly during the pour and is harder to wet through at the start; the shallow bed wets almost instantly and is more prone to channelling, where water finds a route and leaves the rest of the leaf comparatively untouched. This is why large flat leaf — the pressed and unrolled styles — is traditionally brewed in wide, shallow vessels, and why compressed chunks do better in something with depth. It is also why a Japanese kyusu is broad and low while a gongfu pot is small and round: both shapes follow from the leaf they were developed for, rather than from national preference, and using one for the other’s tea is a real handicap.
Choosing for the tea you actually drink
The characteristic failure in teaware buying is acquiring the vessel associated with a style you admire rather than one suited to the tea in your cupboard. Someone who mostly drinks Japanese green tea and buys a small clay gongfu pot has bought the wrong shape, the wrong filter and the wrong volume in a single purchase, and no amount of material quality compensates for any of the three. The order that works is to name the tea, name the method, and then find the vessel that has room for the leaf, drains fast, and empties clean — treating the material as the last question rather than the first. That order also happens to be much cheaper, since geometry is not what teaware is priced on. A plain porcelain gaiwan chosen for its shape will outperform an expensive pot chosen for its clay on almost any tea either could brew.