A tea grade names two things, and only two: the size of the made leaf and how much young golden tip rides in it. It does not measure flavor, and it is not a score. A grade is a sorting label, not a verdict on the cup. The letters describe what the leaf looks like, not how it tastes, and a well-made tea and a poor one can carry the same grade. This is the single point the whole trade trips on, so this office states it plainly first: read the grade for the size and tip it names, then judge the tea by drinking it. Assam reaches the cup by two manufacturing roads, orthodox and CTC, and each carries its own grade alphabet. Both are documented below.

How a tea is graded

Grading happens after manufacture, never before. Once the leaf is made, rolled whole the orthodox way or cut by the CTC machines, it is sorted by size. The dried leaf is run across a stack of mechanically oscillated sieves fitted with meshes of decreasing size, the same sieving principle the UPASI Tea Research Foundation sets out for orthodox manufacture. Each mesh holds back a size band; what falls through to the next sieve is smaller again. What comes off each level is a grade, named for how large the pieces are and how much golden tip the sorter can see in them.

The grader sifts and weighs. The taster brews each line, judges the dry leaf and the liquor side by side, and rules on it. The graded lot then goes to auction. Most Assam sells through the Guwahati Tea Auction Centre, established on 25 September 1970 and, by its own account, the centre that has auctioned the largest volume of CTC tea in the world, where each lot is listed by garden, grade, and invoice number. The grade on a packet is the end of that sorting line, written down.

The four size bands

Every grade name, orthodox or CTC, falls into one of four size bands. Largest first:

• Whole leaf. The leaf kept whole or nearly so. Brews slowest, gives the widest range, holds the most tip. The top of the orthodox shelf, and the only band CTC cannot produce.
• Broken. The leaf cut smaller. Brews faster and brisker, darker in the cup, and makes up most of the loose Assam sold in the West.
• Fannings. Small particles, finer than broken. Fast and bold in the cup. The grade in most tea bags.
• Dust. The finest particles of all. Not floor sweepings, whatever the name suggests, but the smallest sieve size, and the quickest and strongest brewing of the lot. The other half of the tea bag.

Smaller is not lower quality. Smaller is faster and darker in the cup, which is what tea bags and a fast builder's brew are made for. Strength is the valley's stock in trade, and the small grades deliver it on schedule. The bands are the spine of every grade code below: the orthodox alphabet and the CTC codes are both just names for which band a leaf landed in, plus how much tip came with it.

Orthodox: the lettered alphabet

Orthodox leaf is sorted into the alphabet the tea trade is known for. It reads as soup until you take it letter by letter, left to right. Every letter marks size or tips, nothing else. Up the whole-leaf ladder:

• OP, Orange Pekoe: the base whole-leaf grade. Long, even, wiry leaf, little or no tip.
• FOP, Flowery Orange Pekoe: whole leaf carrying some young tip.
• GFOP, Golden Flowery Orange Pekoe: FOP with golden tips in it.
• TGFOP, Tippy Golden Flowery Orange Pekoe: a high proportion of golden tips, a finer pick. This is the main whole-leaf grade in Assam.
• FTGFOP, Finest Tippy Golden Flowery Orange Pekoe: finer still, the highest-quality whole-leaf class.
• SFTGFOP, Special Finest Tippy Golden Flowery Orange Pekoe: the top of the ladder, rare leaf.

A 1 on the end, as in TGFOP1 or SFTGFOP1, marks the best leaves within that grade. Decode the letters one at a time and the mystery drops away:

• O, Orange: a designation, not a flavor and not a fruit. The two likeliest roots are the Dutch House of Orange-Nassau, under whose prestige the early tea was marketed in Europe, and the coppery color of high-quality oxidized leaf before drying. There is no orange in the cup.
• P, Pekoe: a leaf grade, from the Chinese pek-ho (white down), the fine silvery hairs on the young bud.
• F, Flowery: the bud and first leaf are in the mix.
• G, Golden: the tips run golden.
• T, Tippy: a high share of tips.
• F, Finest: a mark of the make.
• S, Special.

More tip means a smoother, maltier cup, and because the buds carry more caffeine than older leaf, a stronger lift in the morning. Tips also set the price, since they are the youngest growth and the most carefully made. Orthodox does not stop at whole leaf: it also produces broken grades, fannings, and dust. The broken band starts with BOP, Broken Orange Pekoe, with a B for Broken on the front; FBOP, Flowery Broken Orange Pekoe, carries some tip. The fannings band is BOPF, Broken Orange Pekoe Fannings. Below that sit the orthodox dust grades. Same four size bands, named with the same letters, with the front of the code telling you which band you are in.

CTC: graded by size alone

CTC has no whole leaf to grade. The machines crush, tear, and curl every leaf into hard, uniform granules, so there is no long wiry leaf to keep, and CTC is sorted on size alone, into broken, fannings, and dust. The granules come off the drier in mixed sizes and are run across the sorting sieves the same way. The codes on an Assam CTC packet:

• BP, Broken Pekoe, and BPS, Broken Pekoe Souchong: the larger granules.
• PF1, Pekoe Fannings 1: the classic tea-bag grade, smaller than BP.
• PD, Pekoe Dust, and D1, Dust 1: the fine grades, fastest and darkest in the cup.

These granular grades are the strength inside most of the tea bags on earth, and the great bulk of Assam's crop is CTC. A PF1 working in a mug with milk before dawn is a tea doing exactly its job.

Reading a packet

Put the letters together and a label decodes in a breath, because each one is a size band plus a tip count and nothing more. Assam TGFOP1 is whole-leaf orthodox, tippy, a fine pick and the best of its grade, one to brew loose and drink with attention. Assam CTC BP is granular, brisk, and built for milk and speed. Orange Pekoe on a supermarket box, with no other letters, usually means a standard whole-leaf black tea, and in North America the phrase has slid further, to mean almost any decent black tea at all. It still does not name a flavor and there is still no orange in it.

What a grade tells you, and what it does not

A grade gives you three things: the size of the leaf, the amount of tip, and so the way to brew it. Longer and gentler for whole leaf, short and hot for the small grades. That is the whole of what it promises. It does not promise a good cup. Two gardens can both ship SFTGFOP1 and brew to very different teas, because make, freshness, and the leaf the garden started with all sit outside the grade. Use the grade to set your method and your expectations of strength and speed. Then settle the tea the way this office always has, by brewing it and drinking it standing up.