Thread Number: 42482
To pre-rinse dishes or not to pre-rinse...
[Down to Last]

Cool Washer Stuff on Amazon:
scroll >>> for more items
Post# 624948   9/14/2012 at 15:46 (2,717 days old) by joefuss1984 (Little Rock, AR)        

joefuss1984's profile picture

Here is the official answer from Bosch!

CLICK HERE TO GO TO joefuss1984's LINK

Post# 624949 , Reply# 1   9/14/2012 at 15:47 (2,717 days old) by joefuss1984 (Little Rock, AR)        

joefuss1984's profile picture
Post# 624964 , Reply# 2   9/14/2012 at 16:37 (2,717 days old) by logixx (Germany)        
No leather pants?! Oh nein!

logixx's profile picture
Well, at least he’s got that 'German dude trying to speak English' accent down. Not sure if I find this funny or embarrassing. Cultural stereotypes aside, Hans, no, Manfred is right, of course. I just bought a Bosch dishwasher that draws just .6 gal per fill yet, residual water in cups is always clear. With out pre-rinsing.

Isch liebe meine Bosch dischwascher.

Post# 625029 , Reply# 3   9/14/2012 at 21:27 (2,717 days old) by Maytagbear (N.E. Ohio)        
There's a few things I'd LIKE

to Ask Manfred, but unfortunately, not many of them are about appliances.

Woooooooooof! Just what I LIKE!! Pity Bosch doesn't offer a portable dishwasher (at least as of the last time I looked....)


Post# 625076 , Reply# 4   9/15/2012 at 04:09 (2,717 days old) by donprohel (I live in Munich - Germany, but I am Italian)        
Manfred must be a bit confused...

"If the enzymes in the detergent don't have food particles to feed on, they will eat away at your dishes and make them dull and ugly."

Enzymes digesting dishes? What sort of enzymes does Manfred have in his detergent? Maybe he smoked those enzymes...

Post# 625084 , Reply# 5   9/15/2012 at 06:12 (2,717 days old) by Frigilux (The Minnesota Prairie)        

frigilux's profile picture
I don't buy the "enzymes will eat away at your dishes" explanation, either. The longest wash is the second, main wash which has detergent in it. Most of the surface soils have been flushed away by the pre-rinse or pre-wash.

Post# 625157 , Reply# 6   9/15/2012 at 11:20 (2,716 days old) by jerrod6 (Philadelphia(center city), Pennsylvania)        

The enzymes combined with hot water may damage your glasses.  On my DW the prewash lasts between 8(for small loads) to 13(for normal or large loads) minutes and while it knocks the big stuff off, the small stuck on fine stuff will still be on the dishes. 


In general when I use a cycle that is going to heat the water to 170F combined with detgerent, I will wash the glasses separately in the quick cycle which uses a way lower temperature for the wash.

Post# 625180 , Reply# 7   9/15/2012 at 13:26 (2,716 days old) by donprohel (I live in Munich - Germany, but I am Italian)        
Enzymes and glass

jerrod6: "The enzymes combined with hot water may damage your glasses".

I am not sure at all that enzymes can damage glass.

If I remember correctly, what damages glass in a dishwasher is the so-called "glass corrosion" caused by too soft hot water in the last rinse (which is sometimes even hotter than the main wash)

Post# 625188 , Reply# 8   9/15/2012 at 14:20 (2,716 days old) by Maytagbear (N.E. Ohio)        
Am I the only one

Who thinks Manfred is ein heiss papa?


Post# 625206 , Reply# 9   9/15/2012 at 16:36 (2,716 days old) by jerrod6 (Philadelphia(center city), Pennsylvania)        

I dunno I thought it was hot water combined with detergent that caused glass etching.  Reason I am thinking this is that in my Miele Dw with water softener it will mix hard water with soft water during the wash phase in programs where the wash  temp could go over 131F.  Of course it might also do that in the rinses too.


 So in the automatic cycle(Sensor), pots and pans, cheese, starch, china crystal.... all of these get mixed water,  and all of these except china crystal(113F)  can be over 131, but energy save(or economy) around 121F and normal about 118F,  get no mix of water. 


When I use pots and pans, cheese, or starch I usually omit any type of glasses because these programs have a set temp of 170F during the wash.


One other thing I noticed is that I don't remember  having glass etching problems until enzymes where introduced into DW detergents.  My parents had a 1971 KA Superba and it was using hot water heated by our heating system which kept the water at 180F in order to heat the house.   Never an etched glass.......UNTIL detergents with enzymes where introduced.

Post# 625315 , Reply# 10   9/16/2012 at 05:02 (2,716 days old) by Logixx (Germany)        

logixx's profile picture
When washing glasses in the dishwasher, it is important to select a fast and cool cycle. Too much detergent, long exposure to water and chemicals, too soft water (I think 4 gpg is best says Miele), drastic changes in temp... Many things can cause etching. That being said, I have washed expensive glasses on the 175F cycle without a problem, while cheap ones etch...


Post# 625500 , Reply# 11   9/16/2012 at 20:05 (2,715 days old) by mayguy (Minnesota)        

I don't pre-rinse, and my glasses looks like new, where someone else I know who pretty much pre-wash before putting them into the DW, and they are all etched up big time on the glasses.

Post# 625553 , Reply# 12   9/16/2012 at 23:54 (2,715 days old) by volsboy1 (East Tenn Smoky mountains )        

volsboy1's profile picture

From the Patents I have read which is a lot I know that food activates enzyme detergents at certain temps and it does say that it can damage things if there is nothing in there for the enzyme to attack..I don't even scrape let alone rinse I shake it the sink if that and in

it goes.... I have no problems my L.G. cleans great

Post# 625564 , Reply# 13   9/17/2012 at 02:24 (2,715 days old) by Launderess (Quiet Please, There´s a Lady on Stage)        
How Long Have I Said That? *LOL*

launderess's profile picture
If DW detergents do not find something to attack in dishwater/on dishes they will go to work on some of the machine's interior parts. The caustic chemicals and or enzymes *need* foods, oils, fats, grease, etc to keep themselves busy and in some cases alter themselves into less dangerous compounds.

Washing soda (sodium carbonate) is a large part of most powdered DW detergents. When it comes into contact with fats/oils it makes a type of soap. Without those oils you've got all that washing soda flinging around with nothing to keep it in check. So it will find something such as dish, glass surfaces or whatever.

There is no sane reason to pre-rinse dishes going into an automatic dishwasher today. *Maybe* pre-soak or scrub very badly burnt up pots and pans if one isn't going run that cycle, but otherwise scrape, load and let the machine get on.

Post# 625578 , Reply# 14   9/17/2012 at 05:18 (2,715 days old) by washer111 ()        
Too Right Launderess!

Pre-Rinsing Causes Glasses/Dishes to Etch:

Fair Dinkum! OR:


No Shit Sherlock (Sorry for the use of a profanity!)


Launderess, you have advocated the whole no-prerinsing to avoid etching thing for at least as long as I've been a member. Who here really does pre-rinse without knowing the effects?

Post# 625594 , Reply# 15   9/17/2012 at 08:07 (2,715 days old) by mrx ()        

It depends on how good your dishwasher's filter design is!

In the United States, the traditional approach to dealing with scraps of food in dishwasher was to include a grinder. This resulted in a reasonable outcome, but it could also result in ground food being deposited back on your dishes and also food particles pounding the dishes which can cause glass damage as it's almost like sandblasting, especially if something like ground popcorn kernels or seeds get into the water.

The European approach (at least on well-designed machines) is different. You have a coarse filter and a self-cleaning cone filter.

The usual design (like Bosch/Siemens/Electrolux/AEG etc) has a tube-shaped multi-layer filter with a coarse grill at the top.

Large items of food will sit on the top of the filter and shouldn't block it.
Smaller items (like say for example a pea, a bit of salad, or piece of pasta) will get sucked down into the tubular filter. This is usually two layered with a very fine filter at the outer edge.

The wash pump sucks water horizontally from the sides of the filter forcing the water through all the layers. So, water recirculating in the dishwasher is kept relatively free of particles of food.

The drain pump is connected to the bottom of the filter. When the machine empties, water is sucked downwards, and fine particles are washed out of the filter meshes and sucked down the drain.

The drain pump can comfortably pump away anything that is small enough to pass through the coarse filters.

Typically, all you should need to do is remove any items sitting on top of the filter at the bottom of the machine and clean the filter out once in a while (not every wash!!)
Overall, unless you're just putting in dishes with a whole meal still on them, you shouldn't have that much filter-maintenance to worry about.

Post# 625597 , Reply# 16   9/17/2012 at 08:10 (2,715 days old) by mrx ()        

Explains how to clean the filters


Post# 625629 , Reply# 17   9/17/2012 at 11:11 (2,714 days old) by mrboilwash (Munich,Germany)        

mrboilwash's profile picture
Living on my own I have to pre rinse sometimes, because I don`t want to have smelly dishes sitting for 2-3 days in the DW !

No more problems with etching in years. I use a little less salt than needed for my water conditions and all in one tabs of good quality.

I remember back in the 1990s when chlorinated detergents were still on the maket here, I had much more problems with etched glasses and even the enameled pots had a nasty rough surface.

Didn`t chlorinated detergents contain the even more caustic water glass instead of washing soda?
I`m surprised Manfred blames the enzymes I always thought it`s the caustics ?!?

Post# 625676 , Reply# 18   9/17/2012 at 14:30 (2,714 days old) by jerrod6 (Philadelphia(center city), Pennsylvania)        

Problem might be today's world economy and the proliferation of cheaply constructed glass.  I had glasses from the Crate and Barrel store that etched like crazy within 6 months.   Thing is that they were washed in the same cycles along with other glasses that I have had for 15 years..... and no etching on them, and they are still being used with no etching. 


Now I just take precaution and don't include glasses in any cycle that it going to get to 170F degrees in the wash. 


The one glass I do rinse off and scrape with my fingers under running water  is the one that has been used to consume fiber supplements because the fiber gets into the machine, mixes with hot water and then turns into a thick slime that covers the filter and the drain pump is not strong enough to deal with it.   Wash pump can handle it,  drain pump no.

Post# 625694 , Reply# 19   9/17/2012 at 15:28 (2,714 days old) by washer111 ()        

Interesting description of the filter. 


I know for a FACT that a DishDrawer CAN be used without the Drain Filter (effectively ceasing the filter plate's functionalility). Its actually amazing what a plastic impeller can do, although, it looks pretty serious. Most nasties were gobbled up, so there was no issue there. I did notice an extreme build up in the corners, until the Rinse-Aid dispensed, then everything just sat in the water. Using the Heavy Cycle, or another cycle with 3 Rinses (Delicates) was practical. 


We haven't experienced etching, and I use the Heavy cycle quite often now, to sanitise our dishes (and because there are 3 post-wash rinses! Maybe similar to "Cool-Down," or to get rid of the extra detergent)

Post# 625848 , Reply# 20   9/18/2012 at 07:03 (2,714 days old) by whirlcool (Just North Of Houston, Texas)        

I had glasses from the Crate and Barrel store that etched like crazy within 6 months.

We had the same thing happen to us with some drink glasses bought at C&B. They only lasted about 2 years before they went opaque. And those glasses weren't cheap either.

Post# 625963 , Reply# 21   9/18/2012 at 17:15 (2,713 days old) by jerrod6 (Philadelphia(center city), Pennsylvania)        
3 post rinses? Where can I find this in the USA

Any new DW washer in the USA have 3 full after rinses?  My Miele can do this if the soil sensor detects excess soil or suds in the first after rinse but it was made in 2004 and sold to the USA in 2006.  Anyone know of a DW sold in the USA that will do three full after rinses?  If so tell me,  I might want to buy it and stash it away for future use.

Post# 625980 , Reply# 22   9/18/2012 at 18:25 (2,713 days old) by Launderess (Quiet Please, There´s a Lady on Stage)        
Glassware Etching In Dishwasher

launderess's profile picture
Post# 625981 , Reply# 23   9/18/2012 at 18:28 (2,713 days old) by Launderess (Quiet Please, There´s a Lady on Stage)        
And Furthermore

launderess's profile picture
Post# 625988 , Reply# 24   9/18/2012 at 19:27 (2,713 days old) by DirectDriveDave ()        

I have never had a problem with etched glassware.

Probably the only thing that I have done that doesn't go with the above article is I use heated drying and the incoming water temperature is 120. But this dishwasher is from 2002 so I have no idea if it heats it any further (Normal Wash cycle)

Post# 626046 , Reply# 25   9/19/2012 at 01:46 (2,713 days old) by washer111 ()        

One word: DishDrawer.


I believe the newer models actually post these "secret" rinses, so you really known which cycle is which. 

Post# 1057827 , Reply# 26   1/16/2020 at 19:39 by GELaundry4ever (Killeen tx USA)        

Don't prerinse anything! I recommend Cascade everything! I have been using Cascade since September 5, 2007 and I never prerinsed from then on when I started using it! It was Cascade and Dawn 2 in 1 action packs!

Post# 1057893 , Reply# 27   1/17/2020 at 10:49 by vacerator (Macomb, Michigan)        
dishwahers used to have a

pre-rinse cycle, or "rinse and hold", for when you didn't have a full load, and didn't want to wash them yet. I pre-rinse for the same reason.

Post# 1057902 , Reply# 28   1/17/2020 at 12:21 by Iheartmaytag (Wichita, Kansas)        

iheartmaytag's profile picture

Well since this thread is almost seven  years old, to prevent discussion into perpetuity I will only state.  Pre-wash?  Why?  I have a dog, sometimes they are so clean I don't even bother putting them in the dishwasher.


Post# 1057903 , Reply# 29   1/17/2020 at 12:51 by DADoES (TX, U.S. of A.)        

dadoes's profile picture
I haven't used Rinse Hold since the late 1970s.  Found it causes more odor due to residual dirty water left in the sump and on the dishware.

Post# 1057906 , Reply# 30   1/17/2020 at 13:22 by IowaBear (Cedar Rapids, IA)        

iowabear's profile picture

I'm guilty of pre-rinsing because I only run my dishwasher about once-a-week.


Except for the occasional spider or centipede my home is blissfully pest-free and that's how I like it.  I may be excessively paranoid but "better safe than sorry" is my policy when it comes to bugs.

Post# 1058725 , Reply# 31   1/24/2020 at 23:11 by Ultralux88 (Denver)        

ultralux88's profile picture
I definitely never rinse anything, the dishwasher was made to wash all of this off!

Post# 1058737 , Reply# 32   1/25/2020 at 00:34 by tolivac (greenville nc)        

When I had a dishwasher-had NO choice-had to rinse the food off the dishes-or like the scene in Creepshow--Roaches "cleaning" the dishes for me!Used to run it a few times per week.

Post# 1058738 , Reply# 33   1/25/2020 at 00:41 by Awooff (Peoria, Illinois)        
Glass etching

Ive had issues with etching years ago when detergents were stronger but found using less detergent stopped this. Scraper, non-rinser here and soft water im sure didnt help either.

Step mom was a pre-washer with soap and the whole bit. She would rinse, wash and sometimes rinse again before placing in the dishwasher. -the dishwasher bottom rack is almost completly rusted through from this practice. -the detergents having nothing to work on but the machine parts. All her glasses were etched with that familiar rainbow hue on them..

Post# 1058822 , Reply# 34   1/26/2020 at 01:15 by DaveAMKrayoGuy (Oak Park, MI)        

daveamkrayoguy's profile picture
If you have any good dishwasher, then "DON'T!"...

-- Dave

Post# 1058843 , Reply# 35   1/26/2020 at 08:01 by Turbowash (USA)        

I own Bosh dishwasher and never rinse dishes before loading it. I just scrape food leftovers. But I see my glasses have discoloration.

Post# 1058857 , Reply# 36   1/26/2020 at 13:08 by ozzie908 (Lincoln UK)        
Reply 25 @washer111

ozzie908's profile picture
I wish I had kept my dish drawer it made life so much easier and I believe there is a way to fix it in when you have Quartz work surfaces?
Its the only dishwasher to be as good as the Miele I use now.

Forum Index:       Other Forums:                      

Comes to the Rescue!

The Discuss-o-Mat has stopped, buzzer is sounding!!!
If you would like to reply to this thread please log-in...

Discuss-O-MAT Log-In

New Members
Click Here To Sign Up.

Discuss-o-Mat Forums
Vintage Brochures, Service and Owners Manuals
Fun Vintage Washer Ephemera
See It Wash!
Video Downloads
Audio Downloads
Picture of the Day
Patent of the Day
Photos of our Collections
The Old Aberdeen Farm
Vintage Service Manuals
Vintage washer/dryer/dishwasher to sell?
Technical/service questions?
Looking for Parts?
Website related questions?
Digital Millennium Copyright Act Policy
Our Privacy Policy