This week... washing-up liquid

Are pricey brands better than bargain bubbles? Xanthe Clay rolls up her sleeves to find out

Dirty dishes piling up? Washing up is the chore we do most often. Few of us go through a day without squeezing a bottle of washing-up detergent into the sink; even if there’s a dishwasher for the plates and mugs, some things just make more sense to clean by hand.

Fairy is top of the tree when it comes to washing-up liquid. Scroll through an online supermarket site and chances are that more than half the options on offer are from the Procter & Gamble superbrand. There’s Fairy Original, Fairy Quickwash, Fairy Platinum, Fairy Max Power – the latter promising “easy & effortless cleaning”, “4 x less scrubbing” and “brilliantly clean” results. This comes at a price, mind: Fairy can work out 10 times more expensive than budget ranges, while “boutique” ecobrands come in even dearer.

What is the difference between the troop of Fairies? Reading through the ingredients list on the manufacturer’s website doesn’t help. Fairy Platinum Lemon seems to be identical to Fairy Platinum Quickwash Lemon, except the former includes the catchily named “Poly[oxy(methyl-1,2-ethanediyl)]”, but there is no explanation why washing up should be quicker without it.

Procter & Gamble didn’t respond to my messages, so I rang the company’s customer helpline, where a charming person explained to me that Original Fairy is “an all-rounder”, Platinum is designed for hard water and very greasy dishes, and Max Power is “more about the bottle design” than what is inside it.

The Max Power bottle is indeed neat, an upside-down design that does away with a flip cap, so you can just squeeze-and-go without leaking green gunk all over the draining board. Still, I’m more interested in how well it, and the cohort of other brands, actually work. And yes, I am very much up for “effortless cleaning”.

The eco brands intrigued me, too. After all, the big baddies of the detergent world, phosphates, which cause “algae bloom” in our waterways, are severely restricted these days and not generally used in washing-up liquid. However, detergents are mostly made using petrochemicals, and some degrade much more readily than others. Eco brands generally use plant-based detergents, or at least ones which break down speedily and harmlessly – that said, there is little regulation, so it is worth scrutinising the claims made.

Time to roll up my sleeves, don my rubber gloves and set-to test 16 different washing-up liquids on plates smeared liberally with dried-on egg and Weetabix. I armed myself with a dishcloth and a “scrubby” made by bundling together the nylon nets that oranges come in – a thrifty tip worth trying – and allowed a half teaspoon of liquid for every litre of hand-hot water (50C). For good measure, after cleaning the dishes I added a tablespoonful of old cooking oil to the water to mimic a well used washing-up bowl and washed a third plate. Then I left the plates to drip dry.

Sixteen washing-up bowls later, I had the results and the conclusion that dearer dishwashing detergent might smell nicer, but it doesn’t wash better. So save your pennies, and choose the squeezy that’s easy on your wallet.

How to read the back of the bottle Labelling for detergents is much less strict than for food. The manufacturers need to list ingredients over 0.2 per cent only by category, rather than name, and with rough percentages (so labels read “less than 5%”, “5-15%”, “1530%”, and “over 30%”). A few specifics, including perfumes, disinfectants and preservatives, need listing even below 0.2 per cent. If you want to know more, by law the label has to include a website address where full listings can be found.

The most important ingredients are surfactants, responsible for lifting dirt and holding it in the water. There are three kinds in washing-up liquid:

“ Anionic (negatively charged) surfactants, which include sulfates, sulfonates, and gluconates. They are the most commonly used surfactant, and are great for “particulate soil” (bitty dirt) but not so good with oil.

“ Non-ionic surfactants, such as cocamide, alkyl polyglycosides, and ethoxylates, are better with oil and organic dirt and good in hard water – plus they are less likely than anionic surfactants to cause skin irritation. When your dishwater turns cloudy, it’s down to the non-ionic surfactants.

“ Amphoteric surfactants, such as betaines, can be anionic or cationic, and are the mildest surfactant, often used in baby shampoo. They also combine with anionic surfactants, making them less likely to irritate skin, and work well in hard water.

I tested on plates smeared with dried-on egg and Weetabix and added a dash of cooking oil to the water