Report February 2025

A predicted supply and demand crisis proved to be accurate, and we’ve spent weeks diplomatically negotiating tight specifications to maintain, hopefully improve our quality, brokering a deal between our Japanese partner, their manufacturing, and a temporary supplier upstream until we can consume our own yarn. Dealing with agricultural and culturally foreign mindsets is fraught with complication and risk. Part of our role is to eliminate these.

We’re back in Bangladesh this month to oversee production. Hopefully, we’ll be able to resupply before running out of stock. As we’re planning coloured product in the future, we need to understand dyeing, and its quality control. We’re also making minor transport packaging changes, and need to train our production staff to correctly pack and identify. We’ll also analyse ways to overcome minor issues that seemed impossible to improve until now.

Seasonal growing conditions can never be controlled. Bengal is particularly susceptible to late monsoon drought, tropical cyclones and flooding. Jute is a bast fibre from plants grown best in continually moist oxygenated clay-sand soil, good sunshine, constant temperature, and low wind shear.

Once raw jute arrives at the yarn mill, the process quality control stages begin. This starts with hackling, where operatives open bales, chop root stock and gummy tops from the filament bundles, and thrash over spikes to dislodge impurities. Only the very worst of the root and loose flaws are removed in low grade applications for cost and time reasons.

In a premium quality rope, it presents one of the most critical parts of quality training to explain the reasons why and maintain removal of all root and tops, with extra care to dislodge as many impurities as possible. Waste removal decreases available fibre volume for the price paid.

Jute hair is the end of a filament. We seek methods to eliminate breaks, especially in batching when fibre is stiff, and develop process improvements to further reduce fibre loss, hairiness and nap. 

We’ll be investigating ways to remove yarn join knots. A typical spinning machine will have 104 stations, each only capable of winding 500g yarn onto a bobbin. We use compacted, tightly trimmed weaver’s knots, but these can’t be eliminated and are necessary when 10kg strander machine bobbins are made up, with these also needing to be joined.

Finally, an explanation about batching – the process of raking fibre and dosing with a medium so when stood to fully absorb (piling) the filaments are softened enough to card (comb), draw (align) and spin to yarn.

Jute first began export in the 1770s through the East India Company, effectively ruling Indian Bengal. Dundee Scotland became ‘Juteopolis’, and being a whaling port, Thomas Neigh invented mechanised batching using whale oil in 1833.

Fibre softening requires an oil in water, with a small quantity of emulsifier to mix. Cheaply available white petroleum oil has been used since the early 20th century, known as Jute Batching Oil (JBO). Alternatives include Castor Oil made from Ricin beans, environmentally unfriendly Palm Oil, Rice Bran Oil prone to lipid rancidity, and locally produced Soybean Oil. The method of extracting oil is critical, as is the percentage in batching. How little oil can be used? Is the result soft enough to produce yarn efficiently? How long is the piling time to achieve this?

Batching machines are not standard. We’ve come across rough trough and wheel systems to metal bar conveyors to our state-of-the-art multi-pass reflow system with dust extraction. Low grade fibre requires more oil and/or longer piling. The hydrophilic power of best grade fibre sucks in oil readily. JBO at same quantity as Vegetable Oil Treated (VOT) will pile faster because mineral oil is more aggressive than vegetable.

Batched fibre is piled in heaps, covered with thick Hessian to build heat and absorb oil as the water evaporates. We improved our VOT piling using a force technique, monitoring pile temperature, giving better uniformity in shorter time.

And then there’s batch-to-batch specification, which generally doesn’t factor too stringently in agricultural, horticultural, animal husbandry and haulage industry cordage. It’s something we introduced with the foundation of KOUMANAWA – a very strict yarn manufacturing tolerance specification to ensure product repeatability.