Why We Make Longer Lasting Soap Bars

I want to tell you a story about two soap bars — let’s creatively call them A and B.

On the surface, they looked pretty similar. Both were handmade, naturally coloured, and scented with essential oils. But that’s where the similarity ended.

One bar was significantly smaller than the other — 82 grams compared to 112 grams — though it wasn’t immediately obvious because both came in a kraft box. Most of us don’t think about soap weight when buying, just the price per bar.

If both bars weighed 100 grams, A would cost $8.20 and B would cost $6.20. That’s a noticeable difference in value.

The Real-World Test

These weren’t theoretical bars. A was a soap I purchased while travelling. B was one I made and sell here at Washpool.

I love trying other handmade soaps, so I used bar A during my trip. I was genuinely shocked to discover I’d used the whole bar in just four days — and I was travelling solo. No one else to blame!

By contrast, on a recent family holiday (five people, eight days, one shower), we didn’t even finish a single Washpool bar. That got me thinking...

We often talk about how you can extend the life of your soap bar with good care — but we don’t often talk about what we do during formulation to make sure our bars are long-lasting and high value.

What Makes a Bar of Soap Last?

Bar A was made with three soft oils: olive, coconut, and rice bran. These are economical and common in natural soap — but they’re also the most water-soluble. That means they dissolve quickly and don’t last long in a humid bathroom environment.

Rice bran oil, in particular, is a cheap option — but it’s refined, imported, and not something we choose to use. Instead, we focus on high-quality, Australian-grown ingredients with real skin benefits. Due to the global olive oil shortage, we’ve transitioned to using locally grown High Oleic Safflower Oil from Kingaroy as our core base oil. It offers a similar gentle profile to olive oil, with better supply consistency. We also continue to use organic virgin coconut oil, known for its cleansing and moisturising properties. And for those with sensitivities who prefer the original base, we still offer olive oil in our Scent Free Olive Oil Bar.

To support bar structure and longevity, we include generous amounts of shea butter and cacao butter — both of which contribute to a firm, lasting bar that performs well in daily use.

We also now offer a Tallow Soap Bar — formulated with grass-fed beef tallow, known for its mildness, rich lather, and water resistance. Tallow soap is deeply hydrating and well tolerated by dry and sensitive skin types. It’s a return to traditional values, with a modern understanding of skincare.

The Experiment

Still not convinced? We ran a simple side-by-side test.

We trimmed our Washpool bar (B) to weigh exactly 82 grams, matching bar A.
We placed both bars in 400g of water and let them sit for 45 minutes.
After soaking, we shook the jars for two minutes, removed the bars, and weighed them.

The results:

Bar A started at 82g and dropped to 67g (15g loss)
Bar B started at 82g and went up to 84g (absorbed water, no loss yet)

We let them sit out for another hour to dry.

Bar A now weighed 65g — a 20% total loss.
Bar B weighed 80g — just a 2% total loss.

That’s a huge difference. And unlike Bar A, our bar will dry out and continue to last with good storage and drainage.

So, What’s the Takeaway?

Olive oil is a beautiful base for soap, but it’s not the only choice — and it’s no longer the most sustainable for us. That’s why we’ve thoughtfully transitioned to local High Oleic Safflower Oil for our core range, supported by shea butter, cacao butter, and now grass-fed tallow in select bars.

The best bars combine:

Safflower or olive oil for gentle cleansing
Coconut oil for lather
Shea and cacao butter (or tallow) for rich lather and long life

That’s how we formulate every Washpool soap bar — not just to feel great on your skin, but to give you long-lasting performance and true value for money.

Shop Our Long-Lasting Natural Soap Bars →