How to measure copra moisture: oven, meter and the sample

How to measure copra moisture decides who is right when two numbers disagree. The instrument may be expensive, but if the sample was drawn badly or the method is not written down, the result is still an argument. This note covers three methods that public documents name, a worked calculation, and the small things that move a reading.

How to measure copra moisture: three methods in the documents

We read the three methods below from documents that spell them out. We do not rank them.

Method	What the source says	Note
Air oven	Draft DKS 2466:2018 (Kenya): about 5 g of ground copra, oven at 100 to 102 °C, reweigh until two successive weighings differ by less than 1 mg.	A laboratory reference. Needs time and a precise balance.
Brown-Duvel or equivalent	PCA AO 02 s. 2003 (Philippines): for deliveries of 500 kg or more, by dealers, traders, exporters and oil millers.	The legal mirror we read only names the method. Ask your laboratory for the full procedure.
Calibrated copra moisture meter	The same PCA rule: for deliveries under 500 kg, a meter registered with the PCA provincial office.	Quick at the gate. Only as good as its calibration against a reference method.

The sources are the Kenyan draft, a public review draft and not a final standard, and a legal mirror of the PCA rule, both read on 22 Oct 2026. They are examples from other countries, not Indonesian rules. We have not matched the mirror against the PCA site.

Start with the sample, not the instrument

Copra takes up or gives off water in storage and transport. So a sample from the surface of a pile can differ from one taken deeper. Draw from several points, mix, split, and close the container tightly at once. The Kenyan draft describes a 9 kg composite sample split in three, which matches the routine in the copra sample trail. How many points and how much sample at your mill is a matter to agree with the seller.

A worked oven calculation

The arithmetic is simple. The figures below are an illustration of the method, not a lot result.

1. Weigh the sample before drying: 5.000 g.
2. Dry it in the oven and reweigh until the weight is constant: 4.690 g.
3. The difference is 0.310 g, the water that left.
4. Moisture = 0.310 divided by 5.000, times 100, which is 6.2 %.

Mind the basis. This figure is worked against the starting weight, the sample as received. If your laboratory works on another basis, the gap can look like a measuring error when it is only a different calculation. State the basis in the report.

Rounding and readings close to the limit

The PCA rule puts the base price at 6.0 per cent moisture. What about 6.04? Is it read as 6.0 or 6.1? The answer has to be in the purchase terms before the truck arrives. Keep the figure exactly as the instrument shows it, decimals included, and write the rounding rule separately. An example deduction rule is on the moisture deductions page.

When the meter and the oven disagree

A sensible order of work:

1. Match the sample and lot codes on both reports.
2. Check the form of the sample, whole or ground, and how long it waited before testing.
3. Check the last calibration of the meter, and against which method it was calibrated.
4. Retest from the retained sample at a laboratory both sides accept.
5. Record every result. Never overwrite the first.

What producers say

The Kora product page, SMN Indonesia and AGRIO COCO, all read on 22 Oct 2026, list a moisture limit without naming the method. So a 6 % on one page is not necessarily the same as a 6 % on another. For the standards tables, read copra quality standards.

Large mills publish a looser picture. Musim Mas writes in a blog post (12 Sep 2023) that arriving copra is sorted for impurities, checked for moisture and dried again if needed. It publishes no limit there. The Philippine BAFS bulletin recommends a drying target of 6 per cent, as advice and not as a quality limit.

What the clerk records at the gate

One line per lot: lot and sample code, test time, instrument and its number, the reading as displayed, the clerk’s name and the provisional decision. A full example is in copra moisture at the receiving gate.

If you are discussing Kora copra

The Kora product page read on 22 Oct 2026 lists moisture limits of up to 6 per cent and up to 8 per cent, without a method. So ask for the method and the basis when you request a quotation. The listed figures are on the pages for lower-moisture copra (max 6 %) and smoke-dried copra, and your questions can go through the contact page.