Teapot

The Western teapot: a round body, a spout opposite a handle, and usually a removable infuser basket. It is the vessel most people picture when they hear the word, and its shape is not arbitrary. A teapot is squat and round while a coffee pot is tall and cylindrical, and the reason is heat.

Capacity: 350 ml to 1.5 l
Material: porcelain, stoneware, glass, cast iron, stainless steel
Origin: China by way of Europe, standard in the West since the eighteenth century
Best for: brewing a shared pot Western style

What the pot takes out of the water

°C, on contact and after 4 minutes

Cast iron1200 g
cold vessel80 to 76
pre-warmed90 to 85
Glass400 g
cold vessel90 to 82
pre-warmed90 to 82
Double-walled glass
cold vessel93 to 89
pre-warmed95 to 91

70100

Francl (2024), chapter 7. 500 g of water at 100 °C poured into each pot, measured on contact and after four minutes, each pot cold and then pre-warmed. The glass pot is barely changed by pre-warming because it had little heat to take in the first place. Porcelain is reported cold only, cooling 7 °C over the same four minutes, so it has no row here rather than an invented one.

What it is

A brewing vessel and a serving vessel at once, which is what separates it from a coffee pot. Ceramic coffee pots only serve, so their proportions can be whatever looks right; a teapot has to hold the water at temperature while extraction happens. For a given volume a sphere has the least surface area of any shape, and surface area is where heat escapes, so the closer a pot is to spherical the better it holds its temperature. Sizes run from one cup to six or more; a three-cup pot serves two people with a little over.

What it does to your tea

It governs temperature, and the effect is larger than most people expect. Francl filled pots with 500 g of water at 100 degrees Celsius and measured. A 1200 g cast iron pot pulled the water down to 80 degrees on contact and 76 degrees after four minutes. A 400 g glass pot dropped it to 90 and then 82. A porcelain pot lost 7 degrees over four minutes. In other words a cold pot can take a black tea below its brewing range before the timer starts, and the pot's mass, not its material's reputation, is what decides how much.

What it suits

Anything you want to brew a lot of at once, and anything Western-style: one measure of leaf, a large volume of water, one long infusion. It is the wrong tool for a tea you want to resteep six times, because the leaf-to-water ratio is low and the leaf sits in liquid between pours unless you remove the basket.

How to use one

Warm the pot first, and take this seriously: pre-warming took Francl's cast iron pot from starting at 80 degrees to starting at 90. Add the leaf loose or in a basket large enough for it to expand fourfold. Pouring the water in from a height of about 25 cm pushes the leaves around and speeds up extraction. Put the lid on while it steeps, because an open pot loses heat by convection. Take the infuser out when the time is up rather than leaving it in the pot.

How to choose one

Round beats tall. Heavy beats light if you will pre-warm it and light beats heavy if you will not. Check the lid has a stopper or a catch so it does not fall out mid-pour, check the spout is set high enough on the body that the pot can be filled properly, and check the basket: many pots ship with a basket far too small for the pot's own volume, which quietly makes the pot worse than it should be.

Care and cleaning

Rinse hot, dry with the lid off. Tannin stains inside a glazed pot are cosmetic and come off with bicarbonate of soda. A stained spout is worth clearing, since it narrows and makes the pour worse.

What people get wrong

Judging the material and ignoring the mass. The common claim is that glass does not hold heat and is therefore unsuitable for oolong and black tea. Measured side by side, the glass pot held its water 6 degrees warmer at four minutes than the cast iron one, because it weighed a third as much and so took a third as much heat out of the water on contact. The variable that actually matters is how heavy the pot is and whether you warmed it, and pre-warming closes most of the gap either way.

What it is made of

teabert, the tealytics teapot, keeper of the kettle

Warm the pot. It is ten seconds and it is worth more than most of the gear you could buy instead.

Sources

500 g of water at 100 degrees Celsius fell to 80 and then 76 degrees in a 1200 g cast iron pot, and to 90 and then 82 degrees in a 400 g glass pot Francl, M. (2024). Steeped: The Chemistry of Tea, chapter 7. Royal Society of Chemistry