Apparently pre-rinsing confuses the dishwasher or something. Not doing it leaves me with residue all over the other dishes though 🤷
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This was on QI.
The enzymes in the dishwasher tablets need some dirt to glom onto, to be able to work. So pre-rinsing can make them less effective.
If that were true, dishwashers wouldn’t start with a pre-rinse before the detergent goes in?
Pre rinse recycles the water. So the fats and such the enzymes work on are still there to help the process.
Nah, someone else posted a video that goes through it in detail. The pre-rinse is 10 mins (depending on dishwasher) of splashing plain water around and around to get the grubbiest bits off, then it dumps the prerinse water and gets clean water for the main cycle where the detergent goes in.
One of the key tips in the video was to add detergent in the prerinse detergent section (some open section that lets it go in straight away), or if your dishwasher doesn’t have one then just straight on the door or in the bottom. Just a small amount so the pre-rinse cycle has detergent in it so can get more off before the main cycle.
The only thing I’ve found about putting dishes in dirty is that some fancy dishwashers on the “auto” setting will sense how dirty the pre-rinse water is and set an appropriate wash cycle. If you’ve pre-rinsed, then it won’t find much and will put it on a light cycle. This can lead to dishes not being clean if they are actually really dirty but you rinsed off the loose stuff already. But it can be worked around by just setting the cycle instead of leaving it on auto.
The QI monkeys are just buzzing around on the net finding factoids for the show, you can often find untrue or misrepresented ones.
It was most likely the ‘technology connnections’ youtube channel videos your referencing for anyone curious.
Yes correct. I only saw the one video linked but this is it: https://www.youtube.com/watch?v=jHP942Livy0
Tips I’ve learned that helped:
- use detergent powder instead of pods. It let’s you experiment with different amounts and dial in the right amount for a run. Generic is fine, they all do about the same amount of work.
- Run your faucet till hot water comes out, it makes it so the pre-rinse has more ability to soften crud on the surface of the dishesp
- pre-rinsing the dishes isn’t necessary for cleanliness, but scraping food bits off will mean your debris filter fills up slower so you don’t have to do the gross task of emptying it as often.
- add detergent in the dip on the door. This gives the pre-wash yet again more ability to attack food bits on the first cycle.
- USE RINSE AID. I helps the dishes dry at the end of the wash.
Running your faucet only makes sense if your dishwasher is also hooked up to warm water. (In Germany) I’ve only seen them connected to cold water.
Of all the things. Like what the fuck Germany.
We have 230VAC instead of your guys’ puny 120V, so our dishwashers aren’t handicapped out of the box and can heat their own water. I feel like having to run the tap before doing dishes is an L for the US, not Germany/Europe?
Wat? We have 230v also. We have both 120v and 220/240.
For stoves and ovens, not dishwashers.
For a country that’s all about doing things big, they sure whimped out on their electrical system
In our defense we were very early to having one and everyone was afraid of electricity at the time
I was gonna say in our defence most of us can’t be trusted with high voltage
Electricity in the usa is not weaker than Europe. Since the voltage is half as high, it just takes double the current to do the same work. A heater running 220v at 5 amps and a heater running 110v 10 amps will work exactly the same.
A lot of houses are older than the concept of central heating or running warm water, so there are some homes that don’t have central warm water, but instead small heaters under the kitchen sink/next to the bathroom, which might or might not hook up to dishwashers
Interesting. Why? Do the dishwashers there require only using cold?
In the US, it is always meant to be connected to the hot tap. The first rinse cycle doesn’t heat the water (or doesn’t run long enough for the heater to make it hot, anyway). It depends on the hot water from the line to be maximally effective that first rinse. And once drained and refilled for the wash, the water will get up to temp eventually, but it’s more effective if it starts hotter.
Much the same reason as electric kettles not being as popular in low-voltage countries as in Europe - with higher domestic voltage, the appliance itself can heat the water it uses in a timely manner.
It’s an American thing. Our dishwashers get hot water from the line, there is a heating element, but it is not very powerful due to our lower output electrical sockets.
I’ve heard other countries have washers that are powerful enough to heat their own water, which is why they are attached to the cold water supply.
Do your dishwashers not have different temperature programs? Tap water is generally set at 65ºC here. My dishwasher has a 45ºC program, a 50ºC program, etc. Depending on how dirty your dishes are you can use lower-temp program to save energy. They even make dishwasher pods specifically for lower temperatures. If it always takes in hot water it would need a way to cool it down.
Not for washing. Usually there will be settings like quick wash, normal, heavy and “pots and pans”. There is a high temp and low temp option, but that is for drying the dishes.
I use the “warm up the water” time to rinse dishes as I load them. Seems silly to say “Don’t rinse your dishes but do run your water until hot.” Block that sink and use that water!
- Run your faucet till hot water comes out, it makes it so the pre-rinse has more ability to soften crud on the surface of the dishes.
Why would this matter? Dishwashers aren’t connected to the hot water line.
Seems like some American dishwashers are connected to the hot water line. Probably because the power available from a standard electrical outlet can’t heat fast enough.
As others have pointed out, it can be done albeit with more attention to detail than commercials imply. I wanted to mention the game changer for me was very reluctantly splurging for the expensive high-end tripple soap pods. These really made a big difference in my washer. I look for deals and buy them in bulk.
One of the greatest USian scams to date. Still wastes water btw.
What even is this comment.
Dishwashers use much less water than hand washing dishes.
Are you saying that dish washers are a scam and that they waste water?
Got some facts to back up that position?
Seeing as how piefed hides my comment, why bother? Y’all are gonna downvote it anyway. lol
If it’s a reputable source I’ll mention it everywhere.
Ah but will you get a shirt for it?
Yes
I’ve got my shirt site ready; so you have info on dishwashers wasting water?
It has a purpose when cleaning by hand
I, uh, have to hand wash all of mine so
i rent a house that does not have a dishwasher and i hand washed everything for a while.
i bought a small countertop dish washer, it’s like 2x2 foot or so. you have a house that you stick on the sink tap.
it’s large enough to handle like 3-4 days of dishes, uses less water then hand washing by a lot, and saves so much time, takes not much power.
i just load it up, put some soap inside the trap and some outside, run the water through the pass through until hot and let it run. it cost me about $250 when i got it. it’s been running well for 5 years now
I have an old (must be 20yo) budget bench dishwasher and never have any issue with anything not being clean. Never done pre-wash and often overpack it.
i always, always set my dirties in the sink, drizzle some dawn in/on and soak them in hot water mostly overnight but a minimum of five hours. rinse and load and they come out spotless every time
That sounds like almost as much work as washing by hand!
its not, though. takes less than a minute per dish
So does washing by hand 😆
It’s also basically doubling the water usage.
Some things you can just put in, some things need a long soak and a steel wool scrub.
Fond on stainless? Baked on protein? Ancient debris? You might need to do it manually.
I don’t know, man, just put it through and if it doesn’t come off, LEARN what you can and can’t like a normal human being, jesus.
A good way to start, if you’re an infant, is to soak all your dishes for like 6-12 hours, and inspect to see what comes off easily and what doesn’t.
All this talk about soaking or not soaking is like mormon young adults trying to bend the walls that skydaddy built.
My dishwasher literally doesn’t have a pre-rinse cycle, the first wash is the main one with the powder, so I get to avoid this whole conundrum! By which I mean, I do quickly wash them by hand if there’s any obvious gunk, and no one would realistically tell me not to.
To those curious, it’s this countertop one: https://www.midea.co.il/product/mdwmt030sw-w-il (couldn’t find a product page in any other language)
The compartment for the detergent has no lid, so the powder drops as soon as you close it.
It also does not have anywhere to put rinse aid, but a bottle of some was included when I bought it new. Great attention to details.
By which I mean, I do quickly wash them by hand if there’s any obvious gunk, and no one would realistically tell me not to.
The whole point of this topic is that you’re not supposed to have to do that 😅
I know, but for my dishwasher specifically, you kinda do :D
Looks like there’s something wrong with your dishwasher. I’ve had this effect once on one that couldn’t heat up the water any more.
It depends a bit on what exactly the residue is you’re talking about, but usually it’s grease that wasn’t properly picked up by the water, just redistributed among your dishes. That is usually because the dishwasher detergent did not properly activate, which in turn is usually because the water does not get hot enough. (Never mind some fats also just stay solid at room temperature.)
A properly working dishwasher does not leave any residue on your dishes.
I’ve had the heating element stop working before. Dishes came out warmish and often dirty.
Replaced it and found an added bonus of the troubleshooting paperwork attached to the front kick-plate. This allowed me to reset the system and verify all pieces were operating correctly.
Melted cheese and dried egg yolks are two things that even commercial dishwashers have trouble with.
Whelp, time to break out the industrial dishwasher.
Whats the difference?
This just feeds the dishes to a woodchipper for easy disposal so you can buy new dishes.
Magnificent, what will they think of next?
I usually just wash it twice and it works.
But back when I washed dishes at Cracker Barrel I remember having to scrape that crap off “clean” dishes.
My dishwasher somehow checks how dirty the water is after the first rinse and adjust ms the washing time accordingly, so getting ketchup and sauces from the plates before makes it run shorter.
That may save some time but I don’t think it’d save water. Dishwashers don’t constantly add new water. Itll add water for a rinse, wash it out, and then more water for the clean. I’m sure some dishwashers do a third cycle as well
Are you adding detergent to the pre rinse, or are you just throwing in one of those crappy packets?
Just watched the video someone else posted. My machine doesn’t have a pre-wash section as far as I can tell, but I’ll throw some extra powder into the bottom for the pre-wash cycle and see how it goes.
Yp, started doing that and it worked in mine. You’ll need to do some trial and error to get the right amount, but TC is right.
I swapped $40 pods that gave me 80 loads for $8 powder that lasts hundreds
Indeed! They got it right with powdered dishwasher soap in the first place.
Residue is a sign of too much soap in the dishwasher. Try reducing the amount of soap. Also, it massively helps to put a little bit inside the chamber and not just the soap compartment. The dishwasher has two washes, pre-wash and main wash, and without soap, pre-wash will be almost useless. With soap, it will drastically reduce the necessary amount of soap in the main wash, meaning no more residue for you.
Someone else posted a video that covered this. Some dishwashers (not mine) have a pre-wash spot for putting the soap. In the video, the guy had his spot actually on top of the soap door, so it would be measured but falls straight in with the dishes when you close the door for the pre-wash. He said in the video to just add a tablespoon of dishwashing powder on the door or in the bottom if yours doesn’t have a prewash spot.
I have learnt a lot from that video and all the comments here!
It’s also worth seeing if the dishwasher you have heats up the water or if it just pulls hot water from the boiler.
You’ll be able to tell by seeing which pipe connected to, if it’s connected to cold water then you’re okay, you’re not American and you can relax.
You mean detergent right?
Apologies for the youtube link but this guy fits in nicely with the lemmy crowd and made a 40min video about optimal use of dishwashers and detergent. He does promote a specific powder detergent… but its from a good company 👈👈😎 and backed with science.
https://m.youtube.com/watch?v=DAX2_mPr9W8&pp=ygUhdGVjaG5vbG9neSBjb25uZWN0aW9ucyBkaXNod2FzaGVy
Hmmm I wonder who it could be.
On an unrelated note, down with blue Christmas lights.
You mean detergent right?
Without double-checking your pedantry (or language barrier) via web search, isn’t “detergent” a type of soap?
That is excellent question of semantics. I dont mean to argue semantics but rather clarify dish “soap” vs dish washer “detergent” as that could be the difference between a successful wash that doesn’t leave residue vs any alternative result.
“This guy”!? How dare you disrespect Alec like that! :P
If you’re nerdy enough to be on Lemmy, you’re likely nerdy enough to already be a fan of Technology Connections; just sayin’.
Lmao you right, I was being a little too casual. Gotta put some respec on his name 😂
Alec Watson puts out some top notch content
Also very fair point but happy to spread the word just in case
lol fair enough
That was fantastic, thanks!
Some of the key things were to put separate powder in for the pre-wash (mine doesn’t have a separate pre-wash section as far as I can tell), and to not put so much detergent in. We have soft water, and apparently that means if you fill the thing up (or use a tablet/pod) then you might be using too much detergent which means it might not all come off in the final rinsing stage.
mine doesn’t have a separate pre-wash section as far as I can tell
Then you can just dump the pre-wash detergent directly in.
Yeah I got that from the video, just throw it in since it’s the first cycle anyway.
I was ready to riot if I didn’t see TC in the comments.
I was shocked that I had the opportunity to post it, to be honest.
It’s funny cause i was just talking about this video the other day with someone who didn’t know you have to run the tap hot before starting the machine. It’s just such a good video.
That depends on how far from your machine your hot water heater is, and if your machine compensates for water temp with a heating element or discharging cold water until the temp increases but as a general rule: yeeuh
It also only matters when your dishwasher is hooked up to warm water in the first place. (In Germany) I’ve only ever seen them connected to cold water.
Even if yours has a heating element it’s a good idea to preheat the water. This is covered in the TC video
I wonder if this could be done by the dishwasher with a temp sensor and program at the start of each load (run until hot, drain, start wash). i assume it would hurt their water efficiency claims to dump a bunch of water down the drain at the start of the wash though
It doesn’t have to, just put a heatig element in it. Most dishwasher I’ve seen only hook up to cold water, so running the tap is not going to do anything.
US dishwashers often do have a wimpy heating element. It gets used if you have a setting for extra hot water or a sani-rinse cycle. It wouldn’t be a big deal to have the dish washer heat it’s own water, but it would require either running a 220V circuit to the machine to make it practical or put up with a very long wash cycle.
Though frankly, washing in cold water is fine as long as you scrub well enough. But you do need to do the rinsing in very hot water to finish the job.
Edit to add - I didn’t explain the extra heating to the water well enough. The wimpy heating element doubles to do extra heating of the water and is used for the drying cycle.
I was ready to be perturbed on his behalf, awww.
