Cocopeat Moisture: Wet Weight vs Dry Matter

First confirm the moisture basis

This guide uses moisture expressed on a wet-weight basis: the mass of water divided by the total wet mass. A percentage reported on a dry-weight basis uses a different denominator. Ask the supplier or laboratory which basis it has used before applying a calculation.

For wet-basis moisture, the calculation is: dry matter = wet weight × (1 − moisture percentage ÷ 100). Here “dry matter” means the remaining mass under the agreed measurement method. It does not describe particle grade, buffering, cleanliness or growing performance.

Write the measured pack weight and moisture result together. A nominal bag weight and an unrelated moisture result from another lot do not establish the dry matter in the pack you received.

Worked example: a 25 kg pack at 65% moisture

At 65% wet-basis moisture, water accounts for 16.25 kg of a 25 kg sample. The remaining dry matter is 25 × 0.35 = 8.75 kg. These are illustrative inputs, not a stated Teral product specification.

If the 8.75 kg of dry matter is preserved and the material reaches 20% wet-basis moisture, its resulting total mass would be 8.75 ÷ 0.80 = 10.9375 kg, approximately 10.94 kg. This is a mass-balance calculation, not an instruction for drying or a prediction of final volume.

Compare weights without confusing them with litres

A 10 kg pack at 20% wet-basis moisture contains 8 kg of dry matter. The illustrative 25 kg pack at 65% contains 8.75 kg. Their large difference in wet weight therefore does not imply the same proportional difference in dry material.

You can divide a comparable purchase cost by calculated dry matter to obtain cost per dry kilogram. Keep the currency and delivery scope the same. Use this as one comparison column alongside the product specification, handling requirements and usable-volume test.

Do not calculate expanded litres from moisture percentage alone. You still need an agreed hydration and volume-measurement procedure. Our cocopeat expansion guide explains why declared expansion should be checked separately.

What to ask for with a moisture result

Request the batch reference, sample date, test method, reporting basis and measured sample weight. Ask how the sample was handled between collection and testing. Agree how many packages are represented and whether results are reported individually or as a combined sample.

If moisture is an order acceptance criterion, put the allowed range and measurement procedure in the specification before shipment. Have a laboratory define the procedure where needed; different preparation choices should not silently become different definitions of the product.

Keep the test record with your EC and pH report and packing documents. Together these records provide a clearer description of a batch than weight alone. For a new order, send the required format and measurement basis with your Teral enquiry.