Know Thy Dishwasher

I would like to thank Josephine Cochrane of Illinois. I’d like to, but I can’t. She’s been dead for more than a century. But if I could, I’d thank her for inventing the dishwasher. Personally, I’d give up just about anything before my dishwasher.


I’ll admit to being a stickler when it comes to properly washed dishes, glassware and utensils. If they come out spotted, gritty or cloudy I’m not happy.

If your dishwasher is not turning out beautifully clean, cloudless, spot-free, sparkling dishes, pots, glassware and flatware—without hand washing them first—don’t assume the dishwasher is broken. If it runs, you can make sure it runs well. And you can stop that pre-washing.

Years ago before we remodeled and sold our home in California, I’d lived with a low-end, plain wrap, well-used, 18-year old dishwasher. All was well until I began noticing that it was just not doing well. Dishes came out feeling gritty, glasses were streaked and cloudy, food remained stuck to flatware. Ugh. It was really bad. I assumed my Tappan had lived out its useful life and deserved to be put down.

Not feeling up to a kitchen remodel right then (you know how that goes … new dishwasher cries for new cabinets and that means new countertops which leads to new flooring … ), I set out to find a solution. I learned the problem wasn’t the dishwasher so much as it was the owner operator.

At a total cost of about nine bucks and a crash course in dishwasherology, I had good ol’ Tappan working like new in no time. And I didn’t resort to pre-rinsing. I still refuse to pre-rinse.

DE-GRUNGE. Just like a car, a dishwasher needs routine maintenance. From time to time you need to get rid of lime scale, soap scum, iron and grease that builds up in your dishwasher. You may be able to see stains and other crud, but much of this is hidden in the hoses and other out-of-sight places. It needs a monthly “acid bath.” You can do this with unsweetened lemonade Kool-Aid, Tang powdered drink mix or a products called Dishwasher Magic (about $9) or Affresh (about $6). All of these products contain citric acid. Dishwasher Magic and Affresh  safely and effectively removes lime scale, iron, soap scum, grease and food stains that build up inside the dishwasher. Unlike the drink powers, Dishwasher Magic also kills 99.9% of germs and extends the life of your dishwasher while improving its cleaning performance. If you use the drink powders, fill both detergent cups with Tang or pour one package of the lemonade powder into each of the cups. Run the empty dishwasher through a complete cycle. If you opt for Dishwasher Magic follow the package directions. I credit Dishwasher Magic with giving that old Tappan dishwasher another six years of useful life.

WATER TEMPERATURE. To effectively clean dirty dishes, a dishwasher needs 140 F. water. And it must enter the dishwasher that hot. If you raise your water heater temperature, beware of the hotter water’s potential for scalding at sinks, showers, bathtubs and in your washing machine. (You can get scald protection devices for sinks and tubs that children use.) The single most important factor in getting good results is hot water. Water should enter the dishwasher at 140 F*. If your dishwasher is newer, it may have its own in-line water heater. Check your manual.

DETERGENT. It’s difficult to beat the Cascade lineup of powdered products, but Costco and Walmart store brands come pretty darn close. Gel detergents of any brand, however, are the scum of the earth. They create more problems than they resolve. Gels contain chlorine bleach, never really rinse off the interior tub, clog the detergent dispenser, don’t work well in hard water and leave spots—in my opinion. Make sure you use fresh powdered automatic dishwasher detergent. It loses its ability to clean properly when exposed to humidity and air. Unless you are a heavy user, don’t opt for the largest box of detergent and never store it under the sink.

DO NOT RINSE. Scrape food to remove all the chunks, but don’t pre-rinse items for the dishwasher. Automatic dishwasher detergent is highly alkaline and needs the acidity of the food to reach optimum cleaning action. Besides, rinsing wastes time, energy and water.

DETERGENT ALTERNATIVES. I’ve done a lot of experimenting but have not found a reasonable substitute for dishwasher detergent. In a pinch I’ve used a 50/50 mix of borax and baking soda with acceptable results. But on a regular basis it does not produce good results.

RINSE AGENT. A rinse additive like Jet-Dry improves the sheeting action of water and leaves dishes sparkling clear, but it can be pricey. Hint: White vinegar is a reasonable substitute. Fill your rinse additive dispenser with straight white vinegar. Occasionally toss in a cup of white vinegar to the last rinse.

SAVE WATER.  It takes between 6-10 gallons of water to run your dishwasher compared to 9-24 gallons you would consume doing them by hand. So give yourself a break and let your dishwasher do the job Josephine intended for it to do.

*Caution: Water in excess of 120 F. can cause scalding in children and elderly adults. If your dishwasher does not have its own heating device, take proper precautions by installing anti-scald devices or consider installing an in-line water heater for the dishwasher.

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11 replies
  1. Sojourner
    Sojourner says:

    We do not run the dishwasher every day but every two to three days as there are two of us. Does the “do not pre-rinse” advice still stand?

    • Jenny Martin
      Jenny Martin says:

      I run a ‘rinse and hold’ cycle before a full cycle when things have been sitting awhile – but we don’t rinse the dishes unless they are tomato based (to prevent staining plastics). We don’t run the machine every day at home, and only about once a week (or less) at work.

    • Mary Hunt
      Mary Hunt says:

      Why don’t you run the full cycle at the end of the day regardless if the washer is completely full? You will use less water than if you hold them until you do have a full load—assuming you are rinsing everything with hot water. If you are compelled to do this, instead of pre-rinsing, I would use the “rinse and hold” option on your dishwasher. That will use a bit of hot water, but not nearly as much as you are using by hand rinsing.

  2. Jeannie
    Jeannie says:

    I, too, wonder about not pre-rinsing when not running the DW everyday, as Sojourner asked. Also, could you comment on how to prevent etching of glassware? I’ve used Melaleucha gel soap to eliminate etching, but it’s rather expensive. Cascade would be cheaper but I don’t want to ruin my glassware.

    • Mary Hunt
      Mary Hunt says:

      Do you have a water softener system in your home? If so you need to be very careful not to overload on detergent. There can be a definite interaction between the salts in that system (changing the PH) and the detergent. You need to research detergent made specifically to be used with a water softener system. Another possibility: You are a diligent “pre-rinser”! If you are removing all of the food and gunk from your dishes, the detergent is not getting properly activated (think chemistry class!) … so it is rubbing and scrubbing your glassware in a way that it was not designed to do and that too, can cause etching. Good luck with figuring this out! I’m going to guess that you pre-rinse which is an easy problem to fix.

  3. Jenny Martin
    Jenny Martin says:

    In order to get the water as hot as possible, you need to run it at the kitchen tap until hot. The cool water sitting in your pipes will not help your machine run optimally, and makes your inline heater work harder than necessary.

    As for gel detergents, I LOVE Melauca’s Diamond Brite. It is pricy, but it has been working great in my 15-yo Bosch, and I wil admit I rarely clean it. No problems!

  4. JuanitaS
    JuanitaS says:

    What a timely article for me. I just purchased my first dishwasher and used it for the first time this past weekend (I had to research how to load). I used the trial sized Cascade Platinum pods and Platinum Rinse provided with the washer. I guess the pods are considered the same as gel detergent. My water is filtered and softened and I know to use less detergent as a result. Is there anything else I should know? I didn’t pre-rinse but used the soak & wash feature since I will not be using the washer but maybe twice a week.

  5. Lynn
    Lynn says:

    I use Cascade and have done for years. But I cannot put my best bone China Dunoon coffee mugs in the dishwasher anymore. The Cascade wears off the glaze and dulls the cups. I’ve used these cups for 20 years and only noticed the problem a couple of years ago.

  6. Julie N
    Julie N says:

    The real problem with using a dishwasher or running laundry is not so much the machine or the operator. It’s the fact that the government legislated against the use of phosphates in detergents in household (but not commercial) products. The industry has yet to come up with a substitute that functions as well. New products use a range of chemicals trying to duplicate the efficiency of the old phosphate-containing products.
    If you found and used a phosphate-containing detergent (they are out there) in your dishwasher for a week, you would be surprised at how things would clean up. Ditto the laundry. Slime and other problems are a post-phosphate-removal issue.
    Researching the issue indicates that the government may not have even been doing the environment that much of a favor, either.

  7. Judy Atwell
    Judy Atwell says:

    Hi Mary,
    Thanks for the reminder! My dishwasher is running a “clean cycle” as I write. Dishwasher Magic is made of citric acid, which can be found inexpensively in the spice department of middle eastern grocery stores.

    • Mary Hunt
      Mary Hunt says:

      Great tip! That would be similar to using the Kool aid or Tang … citric acid. And I’ve used both of the powdered drink options as maintenance. But for a really badly neglected machine (like my old Tappan) the powdered drink options wouldn’t do it. Dishwasher Magic is very powerful AND kills bacteria even e-coli. I’m not sure that citric acid can claim the same.


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