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Dishwashers, with rare exception, are much better at washing dishes than people are. They can use water temperatures that would burn skin, pressures that would bruise, and can keep going at it for HOURS without getting tired.

People are lazy. They only look for dirty spots and go for those. They intentionally or intentionally avoid cleaning some areas. Dishwashers don't care what 'looks' dirty - they just keep washing.

Even if you think it's clean by hand, chances are there's far more residual residue and bacteria you can't see that a dishwasher wouldn't have any trouble with.

99% of the problem with dishwashers are that people use them wrong:

* They don't clean the filter and spray arms regularly

* They use the shitty pods instead of powder, which is the most effective since it can have bleach

* They don't put some detergent in the pre-wash

* They have a unit that doesn't pre-heat the water and need to just run the faucet for a bit to get the water hot

* They don't use a rinse aid

If you can avoid those 5 mistakes, a dishwasher will always way out-perform hand-washing. Even dirt cheap basic units you see in low end apartments will do an amazing job if actually used correctly.

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nly 2 days ago | parent | next [-]

Good tablets come with a built-ij dose of rinse aid now. The modern multicoloured ones work much better than the compressed detergent ones.

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Night_Thastus 2 days ago | parent [-]

Tablets still can't be split into pre and post-wash and they tend to WAY overdo the amount of detergent, because the manufacturer has no idea how hard your water is.

	▲	Qwertious 2 days ago \| parent \| next [-]
		To be fair, I have no idea how hard my water is either.
	▲	nly a day ago \| parent \| prev [-]
		And yet I've never had any cleaning issues.

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pazimzadeh 2 days ago | parent | prev [-]

You're missing the point. I'm not talking about people lazily washing their dishes by hand. I'm talking about focused hand-washing of dishes with many corners, vs. sticking them in the dish-washer.

Like the article mentioned, to get the best result you need to have your dirty dishes line up with where the water is coming out. So if you need to wash something on multiple sides (including top), handwashing will be better.

Hot water is not what cleans your dishes, it's the pressure from the water washing things out (helped by soap). Heat just softens the gunk and oil. Plus you can wear gloves and/or let dishes soak in hot water so that's not even a factor.

By the way, many microbes can survive heat (in spore form), even boiling hot water. Nothing can survive being washed away by soap though. Well, they could survive, but they won't be on your dish.

As a microbiologist I'm aware that what looks clean can have leftover residue. How are you measuring cleanliness out of a dishwasher? I'm guessing by eye, the same way you're measuring hand-washed dish cleanliness.

The way you talk about dishwashers is like you think they're autoclaves, which can actually break spores down using a high heat only achievable in a high-pressure tank (higher than boiling temperature, around 120 celsius). Your dishwasher is only getting about 50 to 60 degrees celsius.

So no, a dishwasher will not always out-perform hand-washing. And if you're using a new sponge, I bet you the result is comparable or better if your hand-washing technique doesn't suck and you should get about the same result with cold water if you use enough soap.

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yjftsjthsd-h 2 days ago | parent [-]

> As a microbiologist I'm aware that what looks clean can have leftover residue. How are you measuring cleanliness out of a dishwasher? I'm guessing by eye, the same way you're measuring hand-washed dish cleanliness.

So how are you measuring, if not by eyeballing it? Can you swab it and check for microbes? Did you?

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pazimzadeh 2 days ago | parent [-]

Why would that matter? I'm not the one who stated opinions as fact:

> If you can avoid those 5 mistakes, a dishwasher will always way out-perform hand-washing

> Even if you think it's clean by hand, chances are there's far more residual residue and bacteria you can't see that a dishwasher wouldn't have any trouble with.

The inverse statement is just as likely to be true depending on the shape of the dish used, where it's placed in the dish-washer, etc.. You think just because the corners of a weirdly shaped dish doesn't have obvious gunk after coming out of the dishwasher that they are clean? Well, I trust my hand scrubbing method more since I don't have a camera to see where and for how long the water landed in the dishwasher.

You could swab a plate, do a dilution series and count colony forming units but there's no guarantee that the growth conditions of your petri dish will reflect what can grow in your body (i.e. will the spores germinate in your petri dish?)

What is well known is that washing with soap trumps heat (except 120+ degrees celsius), and you don't need to kill bacteria for a surface to be clean (in fact it's better to wash them off than to kill them). The fact that hand-washing is better for scrubbing corners with soap is obvious. Case in point, this burnt/sticky rice leftover on a pot that I stuck in the dishwasher a few hours ago as a test: https://imgur.com/a/wfnxMnZ

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yjftsjthsd-h 2 days ago | parent [-]

You did in fact make several claims of fact, and then followed up with an appeal to authority as a microbiologist. Having those credentials means you probably could have verified your claims, but you don't appear to have done so, so we get to hand-wave at each other.

> What is well known is that washing with soap trumps heat (except 120+ degrees celsius)

The dishwasher uses heat and soap. And it sprays things off, while we're at it.

> The fact that hand-washing is better for scrubbing corners with soap is obvious. Case in point, this burnt/sticky rice leftover on a pot that I stuck in the dishwasher a few hours ago as a test

I will happily agree that hand washing tends to win on mechanical grounds. I think that if the machine can spray off the dishes to the point of being visually clean then it probably left them sanitized as well (again, hot water and soap and spraying is compelling to me), but if there's stuff stuck on the dishes then yes obviously a person scraping it off is going to be better at removing it.

	▲	pazimzadeh a day ago \| parent [-]
		I find it hard to believe that you're still doubling down but only selectively detecting unsupported "claims of fact" without support especially since I made weaker, more situational claims. The original poster commented: > machines wash 1000 times better than hand ever could, uses less water, and doesn’t dry out your hands "Ever could"? "1000 times"? And yet you have a problem with me saying hand-washing CAN be better when have dishes with corners or need to wash both sides of the dish. The next commenter said: > Even if you think it's clean by hand, chances are there's far more residual residue and bacteria you can't see that a dishwasher wouldn't have any trouble with I invoked being a microbiologist to make the point that I'm already aware of the fact that looking clean doesn't equal being clean. None of my arguments rely on my authority as a microbiologist. Anyone with decent reading comprehension can evaluate the broken logic: he's mixing up the fact that cleanliness is not just what something looks like with the idea that the dishwasher must do a better job than hand-washing because you can't tell if something is really clean or not. That makes no sense, and seems to be some kind of appeal to technology or modernity. > I think that if the machine can spray off the dishes to the point of being visually clean then it probably left them sanitized as well This is the exact point that the guy was saying is NOT the case, and as a microbiologist I agreed with him even though it's irrelevant to the argument since neither of us has tested the dishes. >The dishwasher uses heat and soap. And it sprays things off, while we're at it. My whole point was that soap and mechanical washing trump heat. My faucet sprays water, and I can evaluate the cleanliness without waiting 2 hours to see if the probabilistic machine jet spray left residue on my dishes or not.