The one thing to understand first

Indian coffee grading is a physical classification. It describes how the beans were processed, how big they are, and how many defective beans are allowed in the lot. It says nothing whatsoever about how the coffee tastes.

This matters because the grade names look like a quality ladder and are frequently sold as one. Plantation AA sounds better than Plantation B, and it costs more, and it is bigger — but a Plantation B from a well-run estate at 1,400 metres, picked ripe and dried properly, will beat a Plantation AA from a careless estate at 900 metres every time. Size correlates loosely with quality because bigger beans tend to come from healthier plants and better conditions. Loosely.

The grades exist because they solve a commercial problem, not a sensory one. A roaster needs beans of uniform size so they roast evenly — put a screen-13 bean and a screen-19 bean in the same drum and one will scorch while the other is underdone. That is the real function of the whole system.

The four base categories

Everything starts with two variables: which species, and whether it was washed or dried in the fruit. That gives four families, and every Indian grade name sits inside one of them.

Two traps here. First, "Cherry" in Indian usage means natural process, not the fruit and not a flavour note — an Arabica Cherry does not taste of cherries. Second, "Plantation" is not a claim about farm size or ownership; it is simply the trade word for washed arabica, and it is used the same way whether the coffee came from a 400-hectare estate or a two-acre smallholding.

"Parchment" refers to the papery hull that surrounds the bean, which survives washing and is removed later at the curing works. Coffee is stored and traded in parchment because that layer protects the bean. Hence washed robusta being sold as Robusta Parchment.

What the letters mean

The letters are sieve sizes. Indian curing works grade over sieves with round holes, and each screen number corresponds to a hole diameter in millimetres:

• Screen 13 — 5.00 mm
• Screen 14 — 5.50 mm
• Screen 15 — 6.00 mm
• Screen 17 — 6.65 mm
• Screen 18 — 7.10 mm
• Screen 19 — 7.50 mm

A grade is defined by the sieve the beans must sit on top of, and by what percentage must sit there. Plantation AA, for example, requires a minimum 90% by weight retained on a 7.10 mm sieve, with 100% standing on screen 17. The 10% that slips through screen 18 must still be whole beans, not fragments.

The tolerances are the second half of every specification. Top grades allow almost no triage (defective beans pulled out by hand or machine), no blacks, no browns, no bits. Lower grades allow progressively more. "Bulk" means the lot was never size-graded at all — and Bulk specifications differ sharply between families: Plantation Bulk and Robusta Parchment Bulk allow around 2% blacks, browns and bits by weight, Robusta Cherry Bulk allows around 10%, and Arabica Cherry Bulk allows up to about 16%. Bulk is not one thing.

The grade table

These are the working specifications used by Indian curing works. Percentages are minimum retention by weight on the stated sieve.

Peaberry, and why PB is different

A normal coffee cherry contains two seeds, each flat on one side where they press against each other. Occasionally only one of the two ovules is fertilised or develops, and the single seed grows round, filling the whole cavity. That is a peaberry, graded PB.

It is a natural mutation and occurs in a small proportion of any harvest — commonly quoted at around 5%, though it varies by variety, season and estate. Because peaberries are round and roughly uniform, they are separated out on their own and sold as a distinct grade. Notice that in the specification tables PB carries no sieve requirement: the grade is defined by shape, not size, which is why it sits outside the AA/A/B/C ladder entirely.

Does it taste better? The claim is that a peaberry concentrates the cherry's resources into one seed and is therefore denser and more flavourful. There is no robust evidence for this. What is definitely true is that peaberries, being round and uniform, roll and roast differently from flat beans, and a peaberry lot roasts very evenly because every bean in it is the same shape. Some roasters find that alone worth the premium. Treat it as an interesting lot, not an automatic upgrade.

The two flagship grades

Mysore Nuggets Extra Bold is India's marquee washed arabica: minimum 90% retention on a 7.50 mm sieve, 100% on screen 17, whole beans only, no peaberry, no broken beans, no defects. It is a big, clean, visually impressive coffee and it has carried Indian arabica in export markets for decades.

Robusta Kaapi Royale is its counterpart on the robusta side and, to our mind, the more interesting of the two. It is produced by re-grading and re-sorting washed Robusta Parchment AB down to screen-17 whole beans with a zero-defect tolerance. Being washed rather than dried in the fruit removes most of the woody, fermenty character people associate with robusta, and the tight size and defect control means it roasts evenly — something a mixed-screen robusta will never do. RKR has been a quiet component of Italian and European espresso blends for a very long time. There is more on what canephora can actually do in our piece on arabica versus robusta.

Monsooned grades

Monsooned coffee gets its own nomenclature because the process physically changes the bean — it swells and loses density, so it will not sit on the sieve it started on.

• Monsooned Malabar AA — minimum 90% retention on a sieve between screens 18 and 19, around 7.25 mm. The top monsooned arabica grade.
• Monsooned Basanally — minimum 75% on a sieve between screens 16 and 17, around 6.50 mm.
• Monsooned Arabica Triage — minimum 90% on screen 15, with a wider defect tolerance.
• Monsooned Robusta AA — minimum 90% on screen 18.
• Monsooned Robusta Triage — minimum 75% on screen 15.

Both Monsooned Malabar Arabica and Monsooned Malabar Robusta hold Geographical Indication registrations in India, filed by the Coffee Board. We have written about how the process works and who it suits in our piece on Monsooned Malabar.

Density, defects, and what actually predicts a good cup

Two things people expect to find in the grade table and will not.

Bulk density is a real and useful measurement — how much a given volume of green coffee weighs, usually expressed in grams per litre. Denser beans generally indicate slower maturation at higher altitude, and density is used operationally in curing works, where gravity and densimetric tables separate heavy beans from light ones. But density is a sorting criterion and a quality indicator, not part of the Board's published grade definitions, which are built on sieve retention and defect tolerance. If a seller quotes you a density figure, that is useful extra information, not a grade.

Cup score is not in the system at all. The Indian grade nomenclature predates specialty cupping by decades and was never designed to carry it. A coffee sold on a cupping score will state that score separately — SCA points for arabica, or a CQI fine robusta score for canephora.

So when you are actually buying, here is the order in which the information is worth something:

• Estate name and altitude — tells you the most
• Variety and processing detail — tells you the shape of the cup
• Harvest year and roast date — tells you whether it is still alive
• Cupping score, if there is one
• Grade — tells you the bean size and how clean the lot is

Grade last. It is genuinely useful information about uniformity and cleanliness, and a roaster needs it. It is just not the answer to "is this good coffee". For the terms that come up alongside these on a bag, see our coffee glossary, and for where in India each of these actually grows, our estate map.