Turmeric Fingers, Bulbs and Powder: Curcumin, Polish and Varieties

This guide will help you choose between turmeric fingers, bulbs and powder, understand what curcumin figures mean, and write a specification that fits your end use.

India is the world's largest producer and exporter of turmeric. The trade has its own vocabulary of forms, finishes and regional names. Knowing it saves time when comparing offers.

From field to fingers

Turmeric is the dried rhizome of Curcuma longa. It is planted around the start of the monsoon and harvested after eight to nine months, so in India the main harvest runs from about January to March. New-crop arrivals reach the big markets in spring.

After harvest, the rhizomes are:

1. Cured (boiled) in water for up to an hour until soft. Boiling gelatinises the starch, spreads the colour evenly and speeds drying.
2. Dried in the sun or in driers, often for 10–15 days in the sun, until hard.
3. Polished to remove the rough outer skin and root bits.
4. Graded into fingers, bulbs and splits.

Fingers, bulbs and splits

• Fingers are the secondary rhizomes that branch off the main one. They are long, slim and the most traded form. Most whole turmeric exports are fingers.
• Bulbs are the round central "mother" rhizomes. They are often a little cheaper. Grinders use them alongside fingers.
• Splits are bulbs cut in half or quarters before curing, to dry faster.

For grinding, fingers and bulbs can both work. For retail whole turmeric, buyers prefer clean, well-formed fingers.

Polished vs unpolished

Unpolished turmeric keeps a rough, dull, sometimes scaly surface with bits of root.

Polished turmeric has been rubbed in rotating drums lined with abrasive mesh, or by hand, to give a smooth, even surface. You will see offers for "single polished" and "double polished". Double polished has had a longer or second pass and looks smoother and brighter. Polishing removes some weight, so it costs more per kg.

Some processors sprinkle a turmeric-and-water slurry during polishing to give a more uniform yellow. That is turmeric on turmeric. The real risk is artificial colour. Lead chromate has been found added to turmeric in parts of South Asia to brighten it. Buyers should test for lead and for synthetic colours, and should not accept unusually bright, uniform colour without a lab report.

Curcumin: what the number means

Curcumin is the main colouring compound. Buyers grinding for colour, or extracting curcumin, pay for higher levels. Indian turmeric typically ranges from about 2% to over 5% curcumin, with some regional types higher.

Three cautions:

• Method matters. Spectrophotometric methods (the older ASTA method) tend to give higher figures than HPLC. Agree the method in the contract.
• "Curcumin" vs "curcuminoids". Some reports give total curcuminoids (curcumin plus two related compounds). That figure is higher than curcumin alone.
• Lot variation. The same variety can vary year to year with soil, weather and curing. Ask for a test on the actual lot.

Regional types, in general terms

Indian turmeric is traded under names tied to region. These names describe origin and typical character. They are not a guarantee of curcumin level.

Main trading markets include Erode, Nizamabad, Sangli and Warangal. Prices at these markets set the reference for export offers.

Turmeric powder

Powder buyers should spell out:

• Curcumin (with test method)
• Mesh size: for example 60 or 80 mesh
• Moisture: commonly 10% max
• Total ash and acid-insoluble ash: high values point to soil or sand
• Colour: by curcumin, not by eye
• Lead and heavy metals: the EU limit for lead in root and rhizome spices is 1.5 mg/kg
• No added colours or starch: ask for tests for synthetic dyes and starch
• Microbiology: Salmonella absent, plus total plate count, yeast and mould limits
• Sterilisation: steam sterilised if you need low microbial counts

Many buyers prefer to import whole fingers and grind at destination. That gives more control over adulteration, freshness and microbiology.

What moves the price

We don't forecast prices, but these factors drive the market:

• Area planted, which follows the previous seasons' prices
• Monsoon rain and disease during the long growing season
• Carry-over stock in the major markets
• Export demand, including from the extraction industry
• Rupee exchange rate

Before you order

• Form: fingers, bulbs, splits or powder
• Polished, double polished or unpolished
• Regional type, if it matters to your customers
• Curcumin minimum, with the test method
• Moisture, ash and acid-insoluble ash limits
• Lead, synthetic colour and pesticide residue tests
• Microbiology and sterilisation for powder
• Pack size, Incoterm and destination port
• Pre-shipment sample and counter-sample

If you are buying turmeric, send us the form, curcumin requirement, pack size and destination port and we'll come back with a written quote.