Tea grades explained: CTC vs orthodox, leaf vs dust, and what each is for

All black tea starts the same way: fresh leaf is withered to reduce moisture, then oxidised until the leaf turns coppery-brown, then dried. The difference between the two families is how the leaf is broken between withering and oxidation.

Orthodox tea is rolled, so the leaf twists and breaks into pieces that keep some structure. It brews slowly, layered and aromatic, and is at its best steeped in water. CTC tea (crush, tear, curl) goes through toothed rollers that cut the leaf into small, dense granules. It brews fast, strong and colourful — the tea for milk chai, tea bags and most of the world’s everyday black tea. Neither is “better”; they are made for different cups.

Orthodox grades use the pekoe system. The base word is OP, orange pekoe, meaning a whole, wiry leaf; letters are added to describe finer leaf with more tips (golden or silver buds). Broken grades are shorter pieces; fannings and dust are the small fractions sifted out after sorting.

• Whole leaf — OP, FOP, GFOP, TGFOP, FTGFOP (with “1” or “SFTGFOP” for a garden’s top selection). Longer names mean more tips and a more careful selection, typical of Darjeeling and premium Assam orthodox.
• Broken leaf — BOP, FBOP, GBOP, TGBOP. Shorter pieces; faster and stronger than whole leaf, still layered in flavour.
• Fannings — BOPF, OF. Small pieces that brew quickly; used in stronger blends and quality tea bags.
• Dust — D, PD. The finest fraction; brisk, dark, quick.

CTC grades borrow the same letters but describe granule size after sifting. The main grades a buyer meets, largest to finest:

• BP (Broken Pekoe) — largest CTC granule; slower, cleaner brew; adds appearance and body to blends.
• BOP (Broken Orange Pekoe) — well-twisted medium granules; a common grade for loose retail packs.
• PF (Pekoe Fannings) — small, even granules; strong, fast extraction; the core of most chai blends and tea bags.
• PD (Pekoe Dust) — very fine grains; near-instant colour and strength.
• Dust (D, CD, RD) — the finest fraction; highest strength and colour per gram; tea bags and very strong chai.

The finer the particle, the more surface area touches the water: faster brewing, darker colour and more strength per gram — and, at the extreme, a coarser, more astringent cup with less aroma. Larger leaf brews slower and lighter with more nuance, but gives fewer cups per kilo and gets lost in milk.

Cup yield is the buyer’s practical yardstick. For a market that boils tea with milk and sugar, finer CTC grades deliver more cups at the expected strength; for a market that steeps tea in water and drinks it plain, larger orthodox or BP grades taste better and yield matters less.

A grade name guarantees a size and a style, not a standard of quality. PF from a well-run Assam garden in the second flush and PF from tired leaf in the rains are the same grade and very different teas. Garden, season, manufacture and the blender’s tasting decide the cup.

So use grades to specify what you want and compare like with like, then judge the tea in the cup. Ask suppliers which gardens and grades sit in a blend and how they keep it consistent; a blender will answer in detail. Narsibapa Tea has graded and blended Assam CTC in Morbi, Gujarat since the 1940s and tastes every batch before packing.

A quick matching guide for the products buyers most often develop.

• Loose retail packs for milk chai (250 g to 1 kg) — a CTC blend built on PF and BOP, sometimes with PD for extra strength. Narsibapa’s retail packs are this style.
• Tea bags — PF, PD and dust; fine, even particles brew fully in a few minutes.
• Food service and roadside chai — dense PF/PD/dust blends for fast, strong, repeatable brewing in bulk pans.
• Premium or gifting lines — larger CTC grades (BP, BOP) for appearance and a rounder cup, or orthodox whole leaf where the market steeps in water.
• Bulk for re-packing — any of the above in 25 to 50 kg sacks (typical), blended to the buyer’s specification.

Terms you will see on offer sheets and tasting notes.

• Liquor — the brewed tea; described by colour, brightness and strength.
• Brisk — a lively, slightly astringent quality; the opposite of flat.
• Body — the weight or thickness of the liquor in the mouth.
• Malty — the rich, cereal-like note of good Assam.
• Flush — a picking season: first (spring), second (early summer, prized in Assam), rains, autumn.
• Infusion — the wet leaf after brewing; bright copper indicates good manufacture.
• Moisture — water content of packed tea; kept low (typically well under 7 percent) for shelf life.