[Jimbee (OP)]

Exactly how much dish detergent are you supposed to use in an average-sized basin? The dish detergent companies say there are no official rules on that. But scientifically, there has to be.

BTW, I err on the side of more. I like the extra cleaning power. It means I have to rinse it more. But I don't mind.

[Origin]

Exactly how much dish detergent are you supposed to use in an average-sized basin?

There is no way to tell you exactly how much soap to use if you don't say exactly how big the basin is.

[alancalverd]

If there are any bubbles left when you have finished the task, you have used too much. When I worked as a detergent chemist we reckoned that at least 90% of washing-up liquid was wasted. Start with two drops, and add more when the bubbles don't form. Or just put a smear on each plate, rub it over by hand, then rinse off with hot water.

But for really good results, to save the planet, and to maximise the utility of your one life,  use a dishwasher - 60 degrees and a really active detergent (hand washing-up liquid contains less than 5% active surfactant) would seriously damage your skin but it cleans sterilises and dries metals and ceramics whilst you do something useful.

[Bored chemist]

Exactly how much dish detergent are you supposed to use in an average-sized basin?

There is no way to tell you exactly how much soap to use if you don't say exactly how big the basin is.

And exactly how dirty the dishes were and...

[paul cotter]

Indeed , BC, but I would suggest a slight modification: it depends on how much grease and oil are adherent to the plates. Most non oily material will wash away but surfactants are needed to solubilise oils and greases. A question for Alan: what the hell is in dishwasher tablets? they destroy the surface of glassware, not labile fluorine surely?

[alancalverd]

I think dishwasher detergents are alkaline (saponifies grease) and likely cationic, whereas handwashing liquids are slightly acidic (so they don't saponify your hands) and definitely anionic. I've not had a problem with cheap glassware (nor do pubs suffer much) but I never put lead crystal in the machine. 

As a gentleman of refinement, I suspect you only sup from Waterford's best, and your butler should know better.

[Petrochemicals]

Enough to dissolve the fat so the bacteria have no where to hide upon drying.

[paul cotter]

I too did a short stint in the detergent industry. The industrial dishwashers(3min cycle?) used sodium hydroxide with a sequestrant which was either edta, nta or atmp and no surfactant. Waterford glass??, not at all, plastic cups reign supreme here!!

[vhfpmr]

add more when the bubbles don't form

I add more when the water starts looking tired, but I find it takes a bit more than that if I want a oily grill pan to feel squeaky clean rather than looking clean but with a slithery greasy feel.

for really good results, to save the planet, and to maximise the utility of your one life,  use a dishwasher

My mother used dishwashers at work, and reckoned that by the time you've pre-washed the dirty stuff before you put it in, and washed the stuff off that the dishwasher missed afterwards you might just as well do the job yourself in the first place. Being as that sounds like having a dog and barking yourself I've never been tempted to try one. (That and the fact that there isn't really room for one.)

really active detergent would seriously damage your skin

Do you know what Bissel put in their carpet cleaner? It stripped all the natural oils out of my skin when I used it to clean the three piece suite, and since then my hands have become permanently intolerant of just about everything.