I got the dishwasher blues
January 29, 2012 12:21 PM   Subscribe

Dishwasher residue buildup. It isn't mineral buildup. What now?

We have a Whirlpool Quiet Partner II dishwasher, about 1 year old, and have been having lots of problems with a grimy/chalky white film on dishes, mostly on glassware. It can be scratched somewhat with a fingernail.

I assumed this was mineral buildup, but for two reasons now, I realize that's not what it is. A few months ago I tested the faucet water with a $25 pool test kit, and the alkalinity came out on the low side. Second, just today I realized I have a vial of 30 molar hydrochloric acid from a rock test kit. It makes a sedimentary rock sizzle and smoke, but it causes no reaction at all on this residue and won't remove it any more than water will.

I tried Googling ideas for what else it could be, but most of what I get are people saying it's hard water and to just throw vinegar or citric acid in the wash. I did do that, of course, earlier when I thought it was hard water, even using CLR and rinse. No change at all.

Last week I disassembled the dishwasher all the way down to the macerator, and found no blockages and just the white film as a white gunk buildup here and there, which I cleaned out. No real improvement after that.

As far as our dishwasher habits, we've used Electrasol liquid and Meyers Clean Day powder. Wash is always with heat, and no sanitary (heat) rinse. I'm suspecting it could be a milk or lactose buildup of some kind since we use a lot of dairy, or maybe even the dishwasher liquid isn't washing off. And this is a longshot but I also worry what if it's a plastic film from the dishwasher internals.

For now, I think I'm going to scrub all the "bad" dishes by hand to try to reset things and make an extra effort to pre-rinse stuff before putting it in the dishwasher. Anyway my questions:

* Any thoughts on what this buildup is? Maybe one of you worked in a restaurant kitchen and have seen this kind of thing. What's a good additive to get rid of it? Vinegar is good for calcium buildup, so likewise maybe there's something that helps cut into dairy buildup if that's the culprit.

* I'd like anecdotes, advice, or links about dishwasher issues where blockages or hard water are already ruled out.

* I heard phosphates were removed from consumer dishwasher liquid, but are still available in commercial liquid. Has anyone gotten hold of the commercial liquid with phosphates (maybe from Amazon or a restaurant supply company) and put it in their home dishwasher? Did it improve things any? I'm not saying I'll get phosphate liquid, especially if it's environmentally harmful... I'm just curious if it's a detergent problem.

* Is there any chance this white residue could be plastic residue condensed or solidified onto the dishes? There is a heating element in there, of course. I guess this is a bit off-topic but I'm finding I really don't like the idea of a heating element and plastic in the same volume... maybe I should've got one with a stainless steel interior, unless the plastic in there is a safe formulation.

Sorry to beanplate this dishwasher thing to death but it's been an annoyance for the past year for me.
posted by crapmatic to Home & Garden (20 answers total) 1 user marked this as a favorite
I have no idea what your buildup is, but I've been a happy user of Dishwasher Magic (which I buy at Target) ever since my dishwasher incident.
posted by ellenaim at 12:29 PM on January 29, 2012

Googling (from Google UK, which gives different results from Google.com) suggests it's probably due to the phosphate-free detergent.
posted by essexjan at 12:30 PM on January 29, 2012

It has nothing to do with your use of milk products. Unless what you have are etched glasses, caused by using too much dishwasher detergent, it is in fact a deposit of minerals from your water supply, the result of using low phosphate detergent. Soaking the pieces in undiluted white vinegar works very well to remove the film, again assuming that your problem is not caused by etching. Works even better if you warm up the vinegar first.

If you want to replace the phosphates in the original formula, you can buy trisodium phosphate from the paint section of the hardware store (it's used to clean walls before painting), or order sodium hexametaphosphate from a supplier for hand dyeing such as Dharma Trading Company, or use a product such as Finish Glass Magic, which contains a bleach combined with the hexametaphosphate water softener.

I can't find the news article I read that claimed that the phosphates in dishwasher detergent are not even the same kind that causes the problem in the bays. I'd like to have more of an idea whether or not that could be true.
posted by Ery at 12:43 PM on January 29, 2012

Lose the powder detergent. Only use liquid. Also, use a liquid rinse agent.

If you can, deselect the Heated Dry selection when you run the washer. Then, when the washing is done, simply open the door wide and let the steam escape and the dishes air-dry. I have a Quiet Partner III, and I've found that the Heated Dry cycle does tend to bake-on a film of some sort. Disabling it has eliminated that and saved a bit on electricity, too.
posted by Thorzdad at 12:56 PM on January 29, 2012 [1 favorite]

I have to use LemiShine or lemon juice now because of the low phosphate detergent. I'd bomb the dishwasher once a month with Dishwasher Magic. I only use half the detergent cup, filled with half power detergent, half LemiShine. I've heard not to use liquid or the 'pill' detergents.
posted by narcoleptic at 12:57 PM on January 29, 2012

It's the lack of phosphates, I think. Someone told me that the gel packets worked way better than the powder -- she recommended Method, I believe, but I wound up at a store that didn't sell it and bought ass-cheap Finish instead. Works a hell of a lot better than Cascade powder, which left me with cloudy residue.

Haven't tried liquid; that might work too.
posted by kestrel251 at 1:10 PM on January 29, 2012

I think what you've got there are silicate deposits:

Different kinds of dishwashing detergent contain different ... Often sodium silicate, this prevents corrosion of dishwasher components .

So far, I've had no success removing these, either.
posted by jamjam at 1:17 PM on January 29, 2012

it is in fact a deposit of minerals from your water supply, the result of using low phosphate detergent. Soaking the pieces in undiluted white vinegar

How so? As I said, I used strong hydrochloric acid, which is extremely reactive with carbonates, which dissolved in water creates hard water. So I should use a weak acid? Sorry if I'm confused about this... if there's something in the chemistry I'm not aware of I'd like to know more.
posted by crapmatic at 1:19 PM on January 29, 2012

HCl wouldn't have any effect on a silicate.
posted by Chocolate Pickle at 1:30 PM on January 29, 2012

Regarding the silicate deposit theory: interesting, and I checked the Meyers bag and it does have sodium silicate. However I was able to wash the film off a glass using lots of detergent and hand-washing and get it almost-new. This suggests either silicate is removable, your glasses might be abraded, or that our film might have some other cause, like oils (my wife thinks it could be peanut butter residue that the detergents aren't removing).
posted by crapmatic at 1:36 PM on January 29, 2012

Try some bar keeper's friend (don't scrub, just dissolve it in some water and rinse the glasses). And/or CLR.

Cascade Complete always worked good for me, and I've seen the opposite advice of Thorzdad. Not to use the liquid stuff because it leaves residue. Something about the powder being designed to be good at dissolving in the water, where liquid detergent just has to disperse mechanically. But in reality, it probably has a lot more to do with how any particular detergent deals with your water's particular ph and mineral profile.

I've also found that "deposits" are really just the dishes not quite getting clean enough. The food and whatever doesn't get completely removed, and the remaining gunk just gets bleached white by the cleaner. What I'll do is to occasionally pop open the washer in the middle of the wash cycle and using a bottle brush, go over all the dishes by hand. They come out beautiful afterwards.

Are there deposits on the bottom of the dishwasher?
posted by gjc at 1:42 PM on January 29, 2012

I had a similar intermittent problem, which seems to be less of a problem if I lighten up on the dishwashing detergent and make up the difference with a little bit of borax, maybe a teaspoon.
posted by 2N2222 at 1:49 PM on January 29, 2012

Possibly what you are seeing is silica etching. Glass is a silicate that can be etched by strong akaline solutions. It is not a mineral building up but a mineral dissolving, the mineral being the silica in your glass. The etching leaves a frosted appearance.

You could try changing detergents to find something less alkaline. You could try using much less detergent to reduce alkalinity. Also pre-rinsing makes things worse since the food residue will offset the alkalinity of the detergent.

My first recommendation would be to use much less detergent. Experiment to find the minimum necessary to clean your dishes and forget pre-rinsing.
posted by JackFlash at 2:00 PM on January 29, 2012 [1 favorite]

If you think it's the phosphate-free detergent, you can buy trisodium phosphate many places and add to your detergent. That's what I do.
posted by Mittenz at 2:14 PM on January 29, 2012

Head dishwasher here. JackFlash is absolutely right on. The #1 problem is almost always too much detergent. If you are brave enough to taste the little white scrapings you'll say, "Yuck, that's detergent." It's not rinsing off entirely and is getting baked on during the dry cycle.

I suggest filling the little dispenser cup only a third or quarter of the way and use a tiny squirt of regular dish soap in the other cup. The regular dishwashing soap really helps break up the heavier detergent and makes everything rinse beautifully.
posted by snsranch at 2:40 PM on January 29, 2012 [1 favorite]

Regarding the silicate deposit theory: interesting, and I checked the Meyers bag and it does have sodium silicate. However I was able to wash the film off a glass using lots of detergent and hand-washing and get it almost-new. This suggests either silicate is removable..


If it's removable by dish detergent, it can't be etching.

On the other hand, you'd expect a detergent containing a silicate to have an ingredient that solubilizes silicates if silicate deposition is a potential problem.

I should have thought of that, but I don't-- we don't-- use our dishwasher at all because I don't want a sheeting agent on things. The residue I tried to get off has been on glassware I've bought used.

Thanks for the tip, by the way.
posted by jamjam at 3:18 PM on January 29, 2012

Here is a page that says deposition of a silica film and the etching JackFlash suggests are parts of a continuum:

reproducing some answers to questions published in Water Technology's popular Professor P.O.U. series. ...

Q: What causes glassware discoloration and etching in dishwashers?

A: Because there are other dishwasher glassware problems that are similar it is important to confirm the particular problem(s) that you are trying to fix. Your question probably refers to two of them. If the glassware has a rainbow-like or yellow coloration it may have what is called a silica film. Some glassware is more resistant to this condition than others. These colors follow existing stress lines in the glass and cannot be removed by acid or bleach but can be scraped off with a sharp knife.


Etching occurs when the causes of colored film are allowed to continue. Signs of this condition are a cloudy appearance that cannot be removed by washing with vinegar (acid), bleach or water.

The cloudiness can be uniform over the surface of the glass or it can be spotty. Unlike the colored film, the cloudiness cannot be scratched off with a knife. Etching is a deterioration of the glass that cannot be reversed. Metal ions have been removed from the glass causing microscopic roughening of the surface. The causes of etching are the same as for silica film, only more time must pass for the etching to occur. ...

and that the things JackFlash and others have suggested are among the causes:

Generally, silica film occurs in softened hard water and is worsened by:

* High water temperatures;
* Poor rinsing caused by overloading the dishwasher;
* Use of high phosphate detergents, which are more aggressive to glassware in softened water; and
* Some glassware is more prone to this problem.

Damage done to the glassware cannot be reversed, but the process can be slowed by:

* Lowering the water temperature to less than 140 degrees Fahrenheit;
* Not overloading the dishwasher
* Using the minimum amount of detergent that will provide clean dishes; and
* Using detergents that have low phosphorous (ask for one that is made for soft water).

Sounds like using detergent by hand removed film, but that some areas already had etching that can't be reversed.
posted by jamjam at 6:28 PM on January 29, 2012

like oils (my wife thinks it could be peanut butter residue that the detergents aren't removing).

For what it's worth, I've found that the pb and margarine residues both leave a crusty brownish stain, not white. In recent years I've taken to half-washing knives that were used for morning toast (Smart Balance or Olivia spread) or p b & j sandwiches, before putting them in the dishwasher, to avoid this (it's a little difficult to scrub off).
posted by aught at 6:41 AM on January 30, 2012

The regular dishwashing soap really helps break up the heavier detergent and makes everything rinse beautifully.

Wait - really? The one time I made the mistake of putting regular dish detergent in a dishwasher (and it was only a little bit) it made a foamy mess that actually came out the vent of the dishwasher door.
posted by aught at 6:43 AM on January 30, 2012

Just had my dishwasher repaired yesterday and he said NEVER....EVER use liquid detergent (even though our ge profile dishwasher insists on using only liquid). He said the best stuff he's found is seventh generation powder. We switched and our dishes are cleaner than ever. He's not the first dishwasher repairman or salesman to recommend against liquid. And yes they're taking out the phosphates which is what breaks through most of the crud and leaves them so clean so that could be a problem as well.
posted by no bueno at 2:07 PM on February 1, 2012

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