This week's Shopping Trolley Hotline has answered the age-old question: which dish soap gives the best suds for your buck?

This week, The Hard Shoulder’s Kieran Cuddihy and reporter Simon Tierney test three washing-up liquid brands on the Irish market: Fairy, Dunnes Stores' own brand, and Ecover.

• Fairy Anti-Leak Washing Up Liquid - €2.50
• Dunnes Antibacterial Eucalyptus Washing Up Liquid 500ml - €1.09
• Ecover 450ml -  €3.25

There was a large price differential found: Ecover was €7.22 per litre, while the Dunnes' product was €2.18 per litre – making Ecover three times more expensive.

While eco-friendly option Ecover may rack up a higher bill at checkout, Simon said the soap is best on sensitive skin.

"All the ingredients are plant-based or natural ingredients," he said.

"What the Ecover is trying to do, is just try trying to prevent you funnelling toxic liquids down into the water system – that's a big deal for a lot of people."

2BWNW6G A woman's hand holds a dishwashing sponge onto which a dishwashing liquid is poured from a white bottle. In the background a sink filled with dirty di

Simon said the ingredients in Ecover versus Dunnes' own-brand soap are quite similar.

"They both have surfactants and surfactant, of course, is the ingredient which creates the foam, the suds, the soap essentially, and they both contain alcohol and perfume," he said.

"The big difference is the type of surfactant that's used – 50% of washing up liquids contain surfactants that are derived directly from fossil fuels, petroleum.

"That's why some less ecologically minded products are so good at cutting through grease because petroleum and crude oil that's in that just cut right through that grease."

Ecover has used yeast that was harvested from a beehive to replace petroleum.

"There are no fossil fuels used in the Ecover, and for an increasing amount of customers, that's really important."

One of Simon's tests involved a bubble metre, where he measured the bubble density of soapy water over time.

"Within three minutes, the bubbles in the own-brand product had reduced by half, the bubbles in the Fairy product had not reduced at all and the bubbles in the Ecover had reduced a small amount," he said.

"The Dunnes product was so noisy, and the reason is because the bubbles were popping really really quickly.

"If you aren't doing the soaking, then you are going to keep those suds there and they're working all the time.

"If you're using the own-branded, within three to five minutes, there's actually not that many bubbles left so they're soaking isn't going to work."

A wine glass immersed in soapy water (Steve Cukrov / Alamy Stock Photo)

The verdict: "If you're dealing with a light soil, I don't think it's gonna make a big difference which product you're using."

"What I will say, I think the Ecover is really worth a go because in my experiments it had just as much penetrative qualities as the Fairy."

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