Versus: Liquid versus bar soap

G Magazine

Don’t get in a lather – we’ve sussed out soap for you.


Credit: iStockphoto

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Despite our societal obsession with cleanliness, the humble bar of soap is starting to fall from favour. “The rise in popularity of liquid soap has continued unabated in recent years with many of the major manufacturers dropping bar soap product lines on a global basis,” says Angela Kidson, senior analyst for market and industry research company IBISWorld.

Less than 20 per cent of personal cleansers sold in Britain are soap bars and while Australian figures weren’t available at the time of going to print, they are likely to be similar.

But is our transition to liquid soap a good thing? Which is better for the environment – liquid or bar soap?


In Australia, all soaps (liquid and bar) are regulated as ‘cosmetics’ under the Industrial Chemicals (Notification and Assessment) Act 1989 and are required to meet certain guidelines.

They can’t be described as having any kind of therapeutic powers, and all of their ingredients must be approved for cosmetic and listed in the Australian Inventory of Chemical Substances, which is regularly updated.

But while the impact of soap ingredients on consumers is regulated carefully, their impact on the environment is not monitored nearly so closely.

An important ingredient in most soap products is sodium lauryl sulphate (SLS), generally sourced from coconut oil or palm oil. The expansion of palm oil plantations in Southeast Asia is responsible for significant deforestation, which means habitat loss for numerous endangered species such as orangutan as well as increased greenhouse gas emissions.

In many cases, the list of ingredients on the product label will not specify the source of the SLS. Not-for-profit organisation Borneo Orangutan Survival has compiled a list of palm oil-free soap alternatives to assist consumers, available at www.orangutans.com.au.

What’s in it?

The basics of soap-making have not changed much in 2,000 years. Soap is one of the products of a chemical reaction between a fatty acid (from either animal or vegetable sources) and lye, an alkaline solution (either sodium or potassium hydroxide).

For stability, transportability and longevity, most commercially produced liquid soap replaces natural fatty acids with a range of laboratory produced detergent compounds such as ammonium laureth sulphate, glycol distearate, stearyl alcohol and others.

Commercially produced personal bar and liquid soaps are usually pH neutral, with the acidic and basic ingredients balancing each other out, says professional soapmaker Lisa Wood-Bradley.

This means they don’t release fatty acids, which cause scum and harmful build-up, into waterways. Compared to most detergents, Wood-Bradley says “they are less likely to harm fragile aquatic ecosystems.”

Handmade bar soaps, however, often have free fatty acids and a high pH, which can damage septic systems unless they are regularly boosted with suitable bacteria and enzymes.

Synthetic colours, oils and fragrances used in soaps can also accumulate in your body, but of greater concern is triclosan, an active ingredient used in anti-bacterial bar and liquid soap that has been found to be a hormone-disruptor in rats and bullfrogs. Registered with the EPA as a pesticide, triclosan has been found in the bodies of wild dolphins, a sign of build-up in the oceanic food web.

Commercial liquid soap usually includes EDTA (ethylenediaminetetraacetic) acid, used in soap as a water conditioner and preservative, which is also a conduit for the take-up of heavy metals. Though sometimes used for soil decontamination after heavy metal pollution, EDTA is an ecologically harmful liquid soap by-product, says Wood-Bradley.

Soaping up

Industrial chemist Emin Safak of Enviro Chemicals says the company sells far more liquid soap than bar soap because consumers recognise it is used far more efficiently.

“Bar soap in a wet environment like a bathroom keeps melting away – plus it harbours bacteria,” Safak says. “In a domestic environment with 1 or 2 users you might consider bar soap, but in business it’s almost always liquid soap.”

However, several studies have found no evidence of the transfer of bacteria as a result of washing hands with previously used bar soap.

Pump packs of liquid soap are designed to measure out a small amount and are consequently used very efficiently until close to the end of the pack. Bars of soap, in comparison, are often thrown out when more than 1/2 of the original soap remains because they have become ‘mushy’.

How is it delivered?

Most liquid soap for domestic use comes in single-use plastic bottles, although many manufacturers do use recyclable PET bottles and low-packaging refills can be purchased to extend the use of smaller pump-packs. In comparison, many soap bars are still supplied in simple cardboard boxes made from recycled and recyclable material.

The advantage flips though, when considering commercial soap use. Liquid soap packaging is far less
wasteful in bulk supply. “We use liquid soap in our 60L Green Building [the eco-building that houses ACF head office] because it can be purchased in bulk,” says ACF spokesperson Sara McMillan.

The verdict

In terms of ingredients that minimise harm to fragile aquatic ecosystems, there are more options for environmentally friendly bar soap than liquid soap. Choose products formulated without palm oil to avoid harm to terrestrial ecosystems.

Bar soap packaging has less of an impact than that for liquid soap. You can prolong the life of bar soap and prevent waste by keeping it on a draining tray.

Avoid anti-bacterial soap – liquid or bar; various studies suggest they bring no hygiene advantage, and cause environmental harm.

G tip: The soap ingredients elaeis guineensis, sodium lauryl sulphate, cetyl alcohol, stearic acid, isopropyl and other palmitates, steareth-2, steareth-20 and fatty alcohol sulphates may be derived from palm oil, so check with the manufacturer.

If buying liquid soap choose larger packs and refills to minimise packaging waste. Avoid anti-bacterial formulations.
At home opt for bar soap and prolong its life by keeping it well drained.
Make your own bar soap using carefully selected sustainable ingredients. It’s a great homemade gift, too!