The KOUMANAWA Report – September 2025
This month we want to give some expert advice on how to inspect raw, unprocessed rope.
When you open the package, and before cutting any strapping, have a long lingering smell. It should have a faintly grassy scent. If it smells of petroleum or kerosene it’s been batched with white petroleum jute batching oil (JBO). If it gives off a rubber odour, the yarns have been coated with a latex, common in carpet backing applications to prevent slippage.
Next is a close visual inspection. Check carefully for impurities Most will be in the yarn even before strands and rope are twisted. Commonly parts of the plant – root, cuticle, bark, etc. still resident in the fibre from poor quality control hackling. While it’s very difficult to remove all small particles, the product should be mostly clean.
Look at the colour. Premium grade raw Tossa jute fibre should be light gold/blonde. As the grades drop the colour will change to a darker gold, then reddish, darker brown, and finally grey – an indication of cheap Meshta fibre from the Roselle (Hibiscus sabdariffa) plant.
Feel the rope by passing it across a sensitive area (eg. wrist). If it feels prickly like fibreglass, it’s been cut with Meshta. If you get splinters, these are commonly from cuticle, Hunka (cambium), bark or waste in the fibre.
Check for imbalances. This is where strands aren’t regularly spaced, and in use will lead to migration with load towards the rope ends.
Open up the strands by gripping ~5cm (2”) apart and turning. Note the lay strength – how strongly the strands want to spring back to form. Look inside for any significant signs of yarns lifting. Small differences are unavoidable in strand-making, but any lifts shouldn’t be greater than the diameter of the yarn.
Check carefully for yarn loops caused by poor tensioning during strand manufacturing.
Cut off ~5cm (2”) of the rope, separate the strands, then separate the yarns from the strands. To maintain balance without recoil each strand should contain an equal number of yarns. Rope should be constructed using single ply yarn. Multiple ply yarns are an indication the supplier has used excess string or twine stock.
An indication of how well production quality has been controlled is to find and analyse any yarn join knots and Habijabi fibre tangles. Yarn join knots should have been made using Weaver’s knots because they compact far better than reef knots and should be tightly trimmed. Habijabi are an indication of poor slither drawing tolerancing.
Check for yarn damage. This can occur due to poor production management of especially stranding machinery where burrs and sharp edges can nick and weaken yarn that when counter-twisted, or subsequently twisted in rope making machinery add rotational stresses that can then break yarn/s hidden within the rope. This is highly dangerous to use for suspensions where yarn damage seriously weakens the rope.
Look at the types of impurities. Small specks of dark material are normal, and very difficult to eliminate during hackling. Long runners of darker root stock have the strength of paper. Cuttings from the harder plant bark, hunka material from the cambium, and waste can all cause scratches or puncture the skin.
Loose laid ‘heavy twine’ cordage intended for agricultural applications is easily prone to damage if not handled correctly.
While it’s possible to carefully dress accidental handling damage, this commonly begins the migration leading to high stranding.
Note that natural raw jute products will still be hairy and have a certain amount of fibre loss. The cleaner the fibre, the easier it is to condition, leading to truly wonderful results. Please find our conditioning advice here: https://koumanawa.com/en/conditioning/
