Mandarin Bath Salts and Bath Oil: Why Oil Needs a Dispersant

Dropping mandarin oil straight into a filled bath is the version to avoid: the oil does not mix with the water, it floats, and it ends up on whatever skin touches the surface. Both recipes here exist to solve that one problem. Make the bath salts first, because they are the simpler project, and make a bath oil only if you will use a dispersant. Neither has been made or tested by us.

Mandarin Essential Oil bottle

Mandarin Essential Oil

Our own Mandarin Essential Oil, in sizes from 0.5 oz to bulk.

From $12.99

Shop Now →

The physics that decides everything

The compound that dominates citrus peel oils, limonene, has a listed water solubility of 7.57 mg/L at 25 C (PubChem/HSDB record, citing Miller and Hawthorne, 2000). We cannot state the limonene content of our oil, because the COA we publish lists only a relative density of 0.852, a refractive index of 1.471 and an optical rotation of +69.80 degrees. A relative density of 0.852 does confirm the batch is lighter than water, so it floats. Reasoning from that: a few drops spread across the surface of a tub, and the first part of you to break the surface carries the oil with it.

Robert Tisserand's dilution guide takes a different view of the same situation: it puts products used in the bath or shower in a 2% to 4% range and notes that the oil disperses in bathwater and is diluted further (Tisserand Institute, undated). Those are general guidelines for essential oils as a class, and the disagreement is worth naming. Our own safety copy for skin sets 0.5% to 2% in a carrier. Given a listed solubility near 8 mg per litre for the main compound, our reasoning is that the water cannot be counted on to do the diluting, and we state only our own range for our oil.

Bath salts: the arithmetic by total weight

Salts are a carrier for the oil, not a dispersant: the oil coats the crystals, and when the salt dissolves the oil is released into the water. Reasoning only, so keep the load low and keep the salts dry and capped. We do not sell salts; they come from a pharmacy (Epsom salt), a grocery store (sea salt), or a craft supplier. Choose the oil share against the total weight of the dry mix. For a 300 g jar:

Oil share of the mixOil by weightOil by volumeDrops (20 per ml)
0.5%1.5 g1.8 mlabout 35
1%3 g3.5 mlabout 70
2%6 g7.0 mlabout 141

The low end is the starting recommendation: 1.5 g in 300 g of salts, stirred in a glass bowl, then spread on a tray to even out before jarring. Weigh the oil rather than counting. Use a measured scoop per bath. Choose one scoop of about 100 g, which at 0.5% carries 0.5 g of oil, about 12 drops, per bath. That figure is arithmetic from a 100 g assumption, not a recommended serving; check the salt supplier's guidance.

Making the salts, step by step

Use a glass or stainless bowl and a spoon you do not mind scenting. Weigh the salts, weigh the oil into a small cup, and drizzle the oil over the salts while stirring, then keep stirring for a couple of minutes so that no clump holds most of the oil. Pour into a clean, dry glass jar with a tight lid and store it away from heat and sun, which the shop's own bulk page says speed oxidation in citrus oils. Fine salts take up oil more evenly than coarse crystals, which is reasoning from surface area, not a tested result. Keep the jar dry: scooping with a wet spoon starts the salts dissolving in the jar. If the mix clumps, it has taken up moisture, and the best fix is a smaller batch next time. Label the jar with the date and the oil share, so that you know the number you chose when you reach for the scoop.

Bath oil: only with a dispersant

A bath oil made of carrier oil and mandarin oil alone will float as a slick, so it needs a dispersant, usually a polysorbate sold by craft and soap suppliers. We found no primary usage figure for the ratio and will not guess one: take the ratio from the supplier's own usage sheet, and ask them what it was intended for. Fix the mandarin oil share first: in 100 g of finished bath oil, 1% is 1 g (about 1.2 ml, 23 drops), 2% is 2 g (2.3 ml, 47 drops). Weigh the carrier and dispersant, stir the mandarin oil into the dispersant first, then add the carrier. For the carrier, our carrier oil guide sets out what to ask. The same untested warning applies: make a small amount, and do a patch test of the finished blend on the inner forearm before it goes near a bath.

The slip problem

Oil makes tubs slippery. A CDC report estimated 234,094 bathroom injuries among people aged 15 and over treated in US emergency departments in 2008, 81.1% from falls, with a rate of 65.8 per 100,000 for injuries in or around the tub or shower (CDC MMWR, 2011). It did not study oils. The report suggests non-slip strips and grab bars, noting more research is needed on their effect. Reasoning from that: rinse the tub after an oil bath, use a mat, and step out slowly.

Who should skip this

Pets should stay out of the bathroom while the tub is in use and the oil is open, per our copy to keep the oil away from them.

What we do not know

We have no data on scent retention in salts, on how long a salt blend keeps, or on how any dispersant behaves with mandarin oil. If you want scrub recipes, the sugar scrub and body oil post covers those, and for dilution, patch tests and sun, see Mandarin Oil Safety Basics. For skin routines in general, using mandarin oil for skin is the broader read.

Start with salts at the low end, use a bowl and a scale, and test on your forearm before you bathe. Make a bath oil later, with a dispersant, once the salts have gone well.

Mandarin Essential Oil bottle

Mandarin Essential Oil

Mandarin Essential Oil from our own shop, in sizes from 0.5 oz to bulk.

From $12.99

Shop Now →

Sources & Further Reading