The short answer
Sieving and grading are the refining steps that sort finished tea by particle size, weight and integrity - sifting through screens of different mesh, blowing air across the stream to lift fluff and dust, and picking out stalks and off-color pieces. The output is not just tidiness: sorting is what makes a grade name mean anything, what makes one carton brew like the next, and what gives you grounds to print whole leaf on a retail pack. When buyers complain that a reorder tastes thinner or looks broken, the trail usually leads back to sorting that was skipped, rushed or quietly downgraded.
The sorting line, step by step
The classic refining pass runs in a fixed order. First comes sieving: vibrating screens separate the stream into size classes - large intact pieces, mid fractions, small particles and fines. Next is winnowing, where air columns separate by weight: light fluff and true dust lift away while sound leaf falls through. Then stalk picking, by machine and often by hand on better lots, removes woody stem and yellowed leaf that would read as defect on a retail shelf. Only after sorting does blending take over, marrying sorted fractions across lots to hold one profile - the consistency step described in the processing guide. A light re-fire or aroma pass may follow, and then the tea is packed. Each removal has a purpose; each skipped pass shows up later in the cup or on the shelf.
What grade names actually describe
Grade names confuse buyers because they describe physical makeup first and quality only indirectly. In the Chinese conventions most of this catalog uses, a grade bundles leaf integrity, uniformity and the share of buds. In the orthodox conventions used for imported blacks, letters describe leaf size and handling - whole leaf grades above broken, broken above fannings, fannings above dust. CTC lines are graded by granule size instead. None of these letters is a flavor verdict by itself; they are size and handling claims, and quality arrives through the leaf and the maker behind the name.
| Sorted fraction | What it is | Where it fits |
|---|---|---|
| Intact leaf / whole grade | Unbroken strips, balls or buds at the top of the sort | Retail loose leaf, gongfu service, showpiece packs |
| Broken grade | Sound leaf, smaller and quicker extracting | Everyday packs, hotel service, bold brews |
| Fannings and small particles | Small fast-extracting fragments | Tea bags, iced and milk-tea bases |
| Granule (CTC) | Machine-shaped particle, size-graded | Bag programs and milk-tea shops at volume |
| Dust and fines | The lightest, finest lift from winnowing | Not a grade we quote for brewed programs |
A practical consequence follows: grade claims should match particle reality. If a pack is sold as whole leaf but the bag pours out broken, that is a sorting or blending failure, and it is checkable against a reference sample in about thirty seconds.
Why uniformity is the real product
Uniform particle size brews evenly - every gram releases at the same pace, so a three-minute steep tastes the same today and next month. Mixed sizes do not: fines over-extract into bitterness while large pieces are still waking up, and the cup lurches between them. Uniformity also protects your claims. A leaf-integrity statement on a retail carton, a brew recipe on a cafe menu, a powder-and-broken-leaf ratio in a lab panel - all of them depend on the sort being stable from batch to batch. Routine finished-tea checks treat this seriously: moisture, ash, the powder-and-broken-leaf share and water extract are standard panel items, run per batch with the sensory five-factor review on top. There is a quieter benefit as well: uniform grades photograph, pack and stack consistently, which sounds trivial until a retail line reprints its cartons because the leaf in the pack no longer matches the picture. Uniformity is brand protection in work clothes.
How sorting and grading interact with blending
Sorting and blending are often confused, so keep the order straight. Sorting divides one batch into size and integrity classes; blending recombines material across batches - and sometimes origins, within what the program claims - to hit one flavor description, season after season. Grading gives blending clean inputs: it is far easier to hold a profile constant when each input fraction is itself uniform. This is also why a blend recipe should be documented against retained samples, as the desk does for every repeated program. When a new harvest arrives and the profile drifts, the fix happens at the blend table, not in the marketing copy.
What a buyer can control
Quite a lot, once you know the vocabulary. You can specify the grade family and leaf-integrity level you expect, and define it against a retained reference rather than an adjective. You can set a ceiling on crumbs and fines for retail packs, since the share of small particles is a routine checkable figure. You can align grade to format deliberately - intact leaf for the wall display, broken or fannings for bags, granules for milk-tea volume - instead of paying whole-leaf prices for a bag program that will never show them. And you can ask which sorting passes a lot actually received, and which were compressed for cost. Suppliers with nothing to hide answer plainly.
Reading your own incoming lots
Three quick checks catch most grading problems before they become customer complaints. Pour a measured scoop onto a white tray and look: uniformity of piece size, honest leaf integrity, and the amount of visible stalk. Brew at your standard parameters and judge whether strength arrives when your recipe says it should. Then check the residue in the strainer - an unexpected load of fines means the sort slipped. Any of the three failing is a reason to compare against the retained reference and raise it with the supplier before shipment, not after.
Grading sits downstream of everything covered in the processing guide and the notes on withering and oxidation and rolling and shaping; how grades are stored and shelf-dated is the companion topic on the grading and storage page. For grade-led lines, compare the CTC and orthodox options on the CTC black tea and Assam pages, and see how the desk's quality-control loop binds grades to references on the quality control page. To get a grade written into a program, send the format and service style through the quote form.