CONDITIONING ADVICE

Design

Both SHIZEN and KOUMANAWA are designed for feel, stability and longevity after conditioning and ‘bedding-in’. Users will note significantly low impurities, fibre loss, hairiness and nap. These are the result of careful selection of premium grade fibre, stringent quality controls, and manufacturing on specialist machinery. Premium grade Tossa presents challenges, especially in regard to hydrophilic action and softness. The higher the grade, the more hydrophilic the fibre, which readily sucks in liquid.

Batching

For fibre to be manufactured to yarn it requires softening using oil in water. Due to availability and economics, it’s commonly made using white petroleum Jute Batching Oil (JBO) which requires less time to soften in piling. JBO effectively kills fibre, making it wiry and less supple so it can be twisted looser with lay suitable for heavy farming twines. Processing can reduce unappealing smell, but residue will always remain present. Both methods weaken integrity. Care must be taken due to toxic gasses emitted. We use no JBO in our production.

Conditioning Butter

The goal is to process raw rope to produce a soft, silky feel. This is best with cold-pressed golden jojoba oil and berrywax (Japan/Mokurō wax), and not beeswax which produces a sticky feel. Berrywax is ideally supplied in pellets, and should be creamy white. Blending should be done in a pan on low heat. First melt wax before adding jojoba oil. Leave to cool before use.

Preparation

Cut ropes to desired lengths. Open strands ~50mm (~2”). Add an overhand knot and compress where the twisted rope meets the open strands for good compaction. This prevents unraveling in tumbling. Jute withstands 193°C before damage. Household tumble driers only reach 80°C. Throw ropes loose into the dryer and tumble for 1 hour. This dislodges loose fibre. Ensure you clear the filter after each cycle. Note how clean the jute dust is after tumbling. Carefully coax each line out of the tangle. Do not apply pressure. Now roughly coat with the oil-wax butter. Premium grade Tossa jute is aggressively hydrophilic. This means if the oil ratio is too high it will be readily sucked in, making your ropes quickly feel dry again. From extensive testing it’s advised to use a 50:50 oil:wax ratio to limit how much is absorbed. Do not throw the ropes loose into the tumble dryer when conditioning as most of the butter will go out of the dryer exhaust and not into the ropes. Instead, hold a block of the butter and draw rope through it once in each direction, applying reasonable pressure. Place your ropes in a cotton mesh laundry bag. You can throw in any butter crumbs into the middle. Close the bag. Tumble on maximum heat for 30 minutes. Applying butter and using a cotton mesh laundry bag helps get the mix into the rope rather than losing it up the dryer flue. When you extract the ropes from the laundry bag you will instantly feel the difference – the ropes having felt a little stiff when raw will now feel soft and silky. At this stage the ropes may be considered ready for use.

Finishing

If you wish, you can finish with a very quick blue flame singe and a final hand coating. However, beware using 100% jojoba oil the fibre is still hydrophilic, and the oil will be sucked in, making the rope feel dry again after a few weeks. To mitigate this, blend jojoba oil with berrywax with an 85:15% oil:wax ratio. Apply the mix to a cloth and pull your conditioned rope through it once in each direction. The addition of the wax will prevent the final oil being sucked into the fibre so quickly, helping it remain on external surfaces. Let hang for 48 hours.

Blending Ratios

Note the specific gravities of jojoba oil and berrywax are not the same. Measure your mixes by weight and not volume. Jojoba oil has a specific gravity of 0.863 and berrywax 0.975. Therefore, your 50:50 mix should be 53 parts oil to 47 parts wax by weight. For the 85:15 mix final hand coating this should be 86 parts oil to 14 parts wax by weight.