What jute batching oil is, and what "JBO-free" really means

Every jute rope you can buy has been treated with oil to make it spinnable. Standard Japanese jute uses a petroleum-derived mineral oil, known as jute batching oil. A growing part of the shibari market sells rope batched with soybean oil instead and calls it “JBO-free”. It is not oil-free; it has been batched with a different oil.

Is JBO dangerous?

The honest answer is that nobody knows what dose a rope delivers, and the people selling you either kind of rope have not measured it.

Here is what we can tell you. The research is real, though every alarming result came from painting undiluted oil onto shaved mouse skin for months. Nobody has published a measurement of what a finished rope leaves on a human forearm.

We do not treat it as a risk worth changing our practice over. We are also not going to tell you it is proven harmless, because that study has not been done either.

If the smell bothers you, or you would simply rather not have petroleum oil on your rope, buy vegetable-batched rope. That is a good reason and we will tell you where.

What JBO is

Jute is a plant fibre. To spin it into yarn the raw fibre has to be softened and lubricated, and the oil is sprayed onto loose fibre before piling and again before spinning. The cohesion the machinery needs and the finished rope’s hand feel both depend on it.

Standard JBO is a crude petroleum distillate. The grade that appears in every study below is JBO-P, described in the chemistry literature as the “non-FDA variety”. That name is doing a lot of work and we will come back to it.

Commercial jute yarn is batched with oil. “JBO-free” is a misnomer: the rope is not free of batching oil. It is batched with a non-petroleum oil instead, usually soybean or another vegetable oil.

What the research actually found

This is a run of papers from the Industrial Toxicology Research Centre in Lucknow, from 1979 to 1989, not the two 1988 studies usually quoted.

1979. JBO painted on mouse skin for up to 300 days produced acne, ulceration and hair loss, and then the animals partly adapted. No carcinogenic change in skin or organs. UV and IR spectroscopy found no polycyclic aromatic hydrocarbons in that sample at all. But JBO applied alongside a known carcinogen shortened tumour latency by about four weeks, which suggested promoting activity. (PubMed 160241)

1986. A different sample, JBO-P, analysed by gas chromatography. PAHs of more than three rings at 3,300 mg/kg, 0.33% by weight. Benzo(a)pyrene at 129 mg/kg. Dibenz(a,h)anthracene at 29 mg/kg. The paper notes the PAH profile was “somewhat similar to that reported for a sample of carcinogenic used engine oil”. (PubMed 3745399)

1987. JBO acting as a tumour promoter in a two-stage assay. Tumours included benign papillomas and keratoacanthomas, and also fibrosarcomas, which are malignant. Total aromatic content of that sample: 11.71%. (PubMed 3803329)

1988, the two that get quoted. One compared whole JBO-P against separated fractions: on their own, only the unfractionated and reconstituted oil produced tumours, all benign, and the isolated fractions failed to produce any up to 40 weeks. The fraction carrying the heavier PAHs did produce tumours once a promoter was applied after it, so the fractions were not inert (PubMed 3250371). The other applied neat JBO-P three times a week and saw skin tumours within 13 weeks (PubMed 3402349).

1989. In the JBO-P-alone group, “100% tumorigenesis was recorded” up to 20 weeks. (PubMed 2781594)

1993. A case report of primary cutaneous carcinoma of the scrotum, indexed under jute batching oil. Occupational, one patient. (PubMed 8229337)

Alongside that, IARC classifies untreated and mildly treated mineral oils as Group 1, carcinogenic to humans. Highly refined mineral oils sit in Group 3, not classifiable. JBO is not listed as a product in its own right, because the classification is by category. And the human evidence names jute processing as one of three occupations, alongside mulespinning and metal machining, where mineral-oil exposure was linked to squamous-cell skin cancer.

We are not going to pretend that is nothing. It is a real result about a real exposure: years of saturated contact in a mill.

The two things nobody has measured

Which grade is on your rope. Compare the 1979 sample, no detectable PAHs and no tumours, against the 1986 JBO-P sample at 0.33% heavy PAHs. Same substance name, completely different oil. Everything alarming in that literature was JBO-P, the non-FDA grade. Which grade a Japanese spinner used on any given batch is not something anybody publishes. We cannot tell you what is on ours. Neither can anyone selling you the alternative.

What transfers from a finished rope. The oil goes onto loose fibre before spinning, so most of it ends up bound inside the yarn rather than sitting free on the surface. How much reaches skin, over an hour, through a wrap, on rope that has been finished and used, is the number that would actually answer the question. As far as we can find, nobody has published it.

Those two gaps are the whole argument. Everything else is inference.

Jute and skin

Jute is a coarse plant fibre. It sheds dust and it is abrasive under tension, especially in a wrap that slides. Redness, itching and small abrasions after a session with new jute are common and are consistent with friction and dust. Stiff rope makes it worse, which is why it eases as rope breaks in.

Reactions to oils on rope also happen. The 1979 paper recorded acne and ulceration on oil-painted skin, so we are not going to tell you the chemistry is never the cause.

We cannot tell you which one you have, and neither can any rope shop. If your skin reacts, stop using that rope and see a doctor or a pharmacist, and take the rope with you. Continuing to tie on a reaction is how a mild reaction becomes a bad one, whatever the cause.

If you process raw jute yourself

This is the exposure worth taking seriously, and it is not tying.

Processing raw jute by hand means repeated, prolonged contact with wet oil. That is far closer in shape to the mill exposure the classification rests on than anything a finished rope does. If you buy a raw roll and work it yourself, wear nitrile gloves, work with ventilation, and do not let oil sit on your hands between passes. Gloves cost almost nothing. Breaking in new jute covers the process itself.

What “JBO-free” suppliers do, and what to make of the claims

“JBO-free” is shop language, not a chemistry term. It means the supplier spun the jute with a non-mineral-oil lubricant. The best-known in the EU is AMATSUNAWA, a German supplier whose pages on JBO and on batching are the most thorough material a shibari buyer can read on the chemistry. Castor, palm and rice-bran versions exist too.

The safety argument that sells vegetable-batched rope rests on real findings. Where we disagree is the step from those findings to a rope in your hands. The animal work used undiluted oil, repeatedly, on shaved skin, for months. The human data is decades of saturated occupational contact. Neither measures what a finished rope leaves on a forearm for an hour.

There is a question worth asking any supplier on either side of this, including us: do you publish residue or PAH testing on your finished rope? As far as we can find, nobody does. Not the JBO-free sellers, not us. A rope sold on a safety claim and a rope sold without one are, on current published evidence, equally unmeasured.

We sell mineral-oil-batched jute, so weigh that, and read the papers rather than taking our summary of them.

What vegetable batching costs you

It is a trade, not a strict improvement.

• Storage. Unstabilised vegetable oils oxidise and can go rancid where mineral oil does not. Fortified variants are formulated against this.
• Allergens. Soy is a recognised allergen. Swapping a mineral oil for a food protein source is a different risk, not an absent one.
• “Food-grade” is not a dermal-safety claim. It means safe to eat, which is a different test from safe against skin for hours under tension.
• Strength. Taking more oil out of jute gives you drier, weaker rope. The cohesion is real, and some finishers re-oil afterwards to make the rope usable again. The choice is which oil sits on the rope, not whether oil sits on it.

What we sell

We import standard Ogawa jute, mineral-oil-batched at source, and clean and hand-finish it in Leuven. It is mineral-oil-batched rope and we do not market it as anything else. We are Belgian-finished, not JBO-free.

Our finished rope has less noticeable mineral-oil smell than the untreated stock. We have not measured its residual oil content, and we are not going to claim a number we do not have.

Our jute ships unoiled, so the conditioning you do is yours. We have also found that once you start oiling or waxing a rope yourself, less of the batching oil comes out of it in use than would otherwise, and there is less smell. Rope care covers which oils and how often.

You may still notice a faint scent when the rope warms up. It fades. Breaking in new jute covers what else changes over the first weeks.

We plan to add a non-petroleum-batched option from a supplier that batches with soybean oil at the spinning stage. It will cost more, because the rope costs more. We have not set a date.

Should you boil our rope

We would not. Boiling weakens the spun yarn every pass, and heat is the harshest thing most people do to a rope. Rope care covers the rest.

What to actually buy

If the smell bothers you, or you would rather not have petroleum oil on rope that touches you, buy vegetable-batched. AMATSUNAWA are in Germany and ship into the Benelux, and their material on soybean batching is the EU reference.

If you want the question settled before you spend anything, it is not settled. The evidence does not show a risk from tying with finished jute, and it does not show the absence of one. We do not treat it as a risk. We would tell you the same whichever rope we sold, which is the part you can check by reading the papers above.

If Belgian-finished Ogawa suits you, we stock it.

The fibre comparison is in POSH vs jute and jute vs hemp. If you are buying a first kit, the starter-kit guide puts this decision in proportion.