--- title: 'Strainers, infusers and tea bags' url: 'https://howtotea.me/teaware/utensils/strainers' markdown: 'https://howtotea.me/teaware/utensils/strainers.md' lang: en date: '2026-10-25' description: 'Strainer, tea ball, basket, press-button flask and tea bag: how they differ, where they came from, which tea each one suits and how to pick the right one.' --- # Strainers, infusers and tea bags 茶滤 Editors · October 25, 2026 · 9 min read A strainer catches the leaf as you pour, an infuser holds it in the water, and a tea bag is an infuser you use once. Each one gets the leaf out of the liquor at the right moment. ![A mesh tea strainer and a steel infuser basket with dry tea](https://howtotea.me/images/c/o/v/e/r/cover-84c166d3.webp) Illustration 茶滤 Strainers and tea bags chá lǜ Job: separate the leaf from the liquor Types: strainer, ball, basket, flask, tea bag Leaf in a ball: about 1 teaspoon Leaf expansion: 2 to 5 times its dry volume Tea bag, black tea: 90–98 °C, 3–4 minutes First tea bag patent: US, granted in 1903 An infuser can be a ball or a basket. You lift it out of the mug with the leaf inside before the liquor over-steeps; a tea bag also comes with the portion already measured. You pour through a strainer from a [gaiwan](https://howtotea.me/teaware/brewing-vessels/gaiwan) or teapot, though gongfu brewing barely needs one: the leaf stays in the gaiwan anyway and the liquor is poured into the [fair cup](https://howtotea.me/teaware/brewing-vessels/chahai). Infusers and bags come from Western brewing, where tea is steeped once, right in the mug. Which one to use depends on the tea and the method. ## The strainer over the fair cup The Chinese name is 茶滤, chálǜ: a mesh or perforated cup on a rim that rests on a fair cup (公道杯) or a mug. The liquor runs through, and leaf fragments and dust stay on the mesh. Strainers are made of stainless steel, bamboo or ceramic. ![Strainer resting on a glass fairness pitcher with leaf fragments in the mesh](https://howtotea.me/images/s/i/t/e/c/sitechko-na-chahae-fe480bca.webp)Illustration The drawback is that it is one more piece to handle, and fine leaf clogs the mesh, so it has to be washed after every session. One Chinese reference on the fair cup claims steel carries an off smell and advises against using a strainer for an infusion you plan to smell. Japanese tea merchant Akira Hojo takes the opposite view: steel barely affects flavor, since the water has already touched steel in the filter and the [kettle](https://howtotea.me/teaware/utensils/kettles). A Japanese [kyusu](https://howtotea.me/teaware/by-region/japan-and-korea/kyusu) has its strainer built into the wall, and it comes in four types: holes in the wall itself (胴穴), a ceramic mesh called ささめ (sasame), a hemispherical ceramic insert, and a steel mesh. Steel drains best and rarely clogs. The most common today is a band mesh running along the whole wall (帯網, obiami): if one patch clogs, the liquor flows through the rest. For deep-steamed sencha (fukamushi, 深蒸し) only steel will do, because ceramic body holes clog by the second infusion. Its oldest Western relative is the mote spoon, made in England from the 1690s to the 1770s: a silver spoon with a perforated bowl and a sharp tip for clearing the spout. The name "mote spoon" only stuck in the 20th century; in the 18th it was simply called a "tea strainer". Museum curators disagree about what it was for: skimming leaves out of the cup or sifting dust from the [caddy](https://howtotea.me/teaware/utensils/tea-caddies). ## Infusers: ball, basket, flask A **ball** (tea ball, tea egg) is two perforated halves on a chain or a spring handle. It is cheap and holds about a teaspoon of dry leaf. That is not much for loose tea: leaf expands 2 to 5 times as it brews, and inside a ball it has no room to unfurl. The soft mesh also dents over time, until the halves no longer close. A **basket** (brew basket) is a cylinder of mesh or perforated steel almost as wide as the mug. Of the simple options, it is the best for loose leaf. Get a deep one so all the leaf sits under water: a short basket rides high in a 470 ml mug, and the tea comes out weak. Woven mesh catches even fine particles and is easier to clean than perforated metal, whose holes trap crumbs. Plastic ones can leave an aftertaste. A **press-button flask** (飄逸杯, piāoyìbēi) is a double flask. Tea goes into the inner flask, which has a mesh and a valve; once it has steeped, you press the button and the liquor drains into the outer flask, leaving the leaf behind. A Taiwanese firm launched it in 1984. It works well for rolled [oolong](https://howtotea.me/teas/oolong), and the maker suggests about 12 g for a 500 ml flask. It is widely copied, and the firm itself says the market is full of imitations. A **press** (French press, plunger) is a beaker with a piston and mesh. It was designed for coffee (a Paris patent of 1852, a spring seal on the piston in 1928), but people brew tea in it too. There are built-in options as well: a removable mesh or porcelain cup that sits under a [teapot's lid](https://howtotea.me/teaware/brewing-vessels/teapot-anatomy), and the automatic tea maker, which lowers a basket at a set temperature (50 to 100 °C in 5-degree steps) and lifts it out on a timer. ## The tea bag The tea bag goes back further than popular articles suggest. The usual story has New York merchant Thomas Sullivan sending out samples in silk pouches around 1908 and customers brewing them as they were. There is little evidence for it, and the paper trail starts earlier. In 1880 Thomas Fitzgerald of Boston patented a muslin bag on a long handle. US patent 723,287, filed in 1901 by Roberta Lawson and Mary Molaren of Milwaukee, was granted on March 24, 1903, for a one-cup pocket of open-weave cotton, "to avoid wasting leaf". In the US the bag went mass-market in the 1920s, first in gauze, then in paper, with a string and a tag. The next step came in Germany. Adolf Rambold's 1944 patent described a folding double-chamber bag[1](#fn:1) made from one rectangular sheet with no glue. He founded Teepack in 1948, and late in 1949 the Constanta machine appeared: it folded a strip into a sleeve, filled it and closed it with a staple. The first machine made 120 bags a minute; modern ones make up to 250. [CTC](https://howtotea.me/brewing/methods/western) tea did as much for the bag as the machine did. In 1930–1931, on the Amgoorie estate in Assam, William McKercher introduced machine "crush, tear, curl" cutting: the small granules brewed faster and stronger and packed neatly into bags. The market did the rest. [In Britain](https://howtotea.me/traditions/europe-and-russia/british-tea), Tetley introduced bags in 1953; they held under 3% of the market in the early 1960s and 96% by 2007. Tetley launched a round bag in 1989, and in 1996 PG Tips brought out a pyramid after four years of development and 25 million pounds. The maker claimed the tetrahedron had 50% more room than a flat bag, but a 2017 study found that tea brews fastest in a double-chamber bag. Bag materials changed over time. Silk proved too expensive, parchment replaced cotton gauze, and long-fiber paper came next (manila hemp, fibers 3–9 mm), with a thermoplastic added so the seam can be heat-sealed. Pyramids are made of nylon, PET or corn-based PLA. The Chinese standard GB/T 24690-2018 requires unbleached cotton thread without fluorescent additives and bans dyes and flavorings inside the bag. A good bag swells but does not tear or leak, and leaves no crumbs in the cup. ## What to brew in which Fine [broken leaf](https://howtotea.me/brewing/basics/leaf-grades) and CTC belong in a bag or any infuser: small particles extract faster, which is why they are packed that way. The bag slows things down, though. In trials with one Assam tea (particles 1.18–1.40 mm), the [extraction](https://howtotea.me/science/water-and-extraction/extraction) rate of [caffeine](https://howtotea.me/science/chemistry/caffeine) from a bag was 29% lower than from loose leaf. The culprit is the layer of still water around the bag rather than the paper, so it helps to move the bag: any motion speeds up the brew. Rolled oolongs such as [Tie Guan Yin](https://howtotea.me/teas/oolong/tie-guan-yin) open further with every infusion, so a ball or a small basket is too tight for them; use a gaiwan, a large basket or a flask. Sencha and dusty teas need a fine mesh, and a gaiwan is awkward with them because small leaf slips past the lid. For chamomile and other small herbs, use a fine weave or a disposable bag. Brewing in a mug One portion (a bag or a full teaspoon of leaf) per cup. [Black tea](https://howtotea.me/teas/black): water at 90–98 °C (194–208 °F), 3–4 minutes; Lapsang Souchong 4–5. [Green tea](https://howtotea.me/teas/green): about 80 °C, sencha 2–2.5 minutes, jasmine 2–3. Lift the basket or bag out first, and only then add milk. This is the guidance of the UK Tea & Infusions Association; for other types, follow the ratios and times for [Western brewing](https://howtotea.me/brewing/methods/western). ## Choosing and caring Choose by the tea, not by the shape. Large leaf and oolongs: a basket, a flask or a gaiwan. Fine leaf and herbs: a fine woven mesh. With a kyusu, check what it is made for ("for fukamushi"): mesh counts are rarely printed on teaware, and there is no common standard for mesh fineness. For [gyokuro](https://howtotea.me/brewing/methods/sencha-gyokuro) and sencha, 80–120 mesh is the usual recommendation. Wash infusers by hand: one basket's plastic and mesh warped in the dishwasher. Take out and rinse the removable band mesh of a kyusu, or mold grows on it. Keep tea bags in a cool, dry place away from strong-smelling food. The rest of the gear around the brewing vessel has its own section, [Utensils](https://howtotea.me/teaware/utensils). ## Common questions Can you brew loose-leaf tea in a tea ball? You can, but a ball holds about a teaspoon of dry leaf, and the leaf expands 2 to 5 times. Cramped like that, it brews weak. Rolled oolongs do not belong in a ball at all: use a large basket, a press-button flask or a gaiwan. Is bagged tea worse than loose leaf? It is different. Bags are filled with fine or broken leaf that brews fast. In trials with the same Assam tea, caffeine came out of a bag 29% more slowly than out of loose leaf. Quality comes down to the leaf inside and the paper, not the shape alone. How long should a tea bag steep in a mug? Black tea needs 3–4 minutes in water at 90–98 °C, green tea 2–3 minutes at about 80 °C. In practice most Britons pull the bag after 1–2 minutes, and the tea ends up weaker than intended. Notes 1. Adolf Rambold, patent no. 914 425, 1944, German Patent and Trade Mark Office, [dpma.de](https://www.dpma.de/docs/postergalerieneu/25_teebeutel.pdf). The year of the double-chamber bag is disputed: Teekanne gives 1949, Guinness 1952. The dates probably mark different events: filing, grant and the machine's launch. [↩](#fnref1:1) --- ## Navigation - Parent: [Tea utensils](https://howtotea.me/teaware/utensils.md) - Previous: [Tea tools: the six gentlemen, pu-erh knife, tea pets](https://howtotea.me/teaware/utensils/tea-tools.md) - Next: [Heat sources for tea](https://howtotea.me/teaware/utensils/heat-sources.md)