Dishwasher soap is a little more difficult to make yourself than dish detergent. Unlike dish detergent, dishwasher soap should include an abrasive ingredient to provide scrubbing action, it shouldn't form suds and it should have an ingredient that handles stains caused by hard water. You may also want to include a pleasant scent, but that's optional.
A Word About Borax
The bulk of do-it-yourself dish-washing detergents contain borax, which is a natural mineral that raises the red flag of toxicity for some people. The U.S. Food and Drug Administration has banned it as a food additive, and the European Chemicals Agency considers it a substance of very high concern. On the other hand, the Material Safety Data Sheet lists borax as a health hazard of 1, which is the same as baking soda and salt. If you prefer to avoid borax, you can still make your own effective dish-washing detergent.
A Recipe that Includes Borax
Writing for House Logic, Courtney Craig describes a series of tests she conducted using a variety of ingredients. After trying out six recipes, the one she found most effective includes unsweetened lemonade mix, which is essentially crystallized lemons. Citric acid is probably a suitable substitute. To make the detergent, she combined the following ingredients:
- 1 cup of borax
- 1 cup of washing soda
- 1/2 of cup kosher salt
- 5 packets of unsweetened lemonade mix
- 1 or 2 drops of essential oils for fragrance (optional)
The recipe produces enough for 42 loads, assuming you use 1 tablespoon per load. If your dishes are extra soiled, however, you may want to use 2 tablespoons.
A Borax-Free Recipe
Health blogger Robin Konie reports getting results that compare favorably to borax-based detergents with a recipe that uses baking soda instead:
- 1 1/2 cups of citric acid
- 1 1/2 cups of washing soda
- 1/2 cup of baking soda
- 1/2 cup of sea salt
- Fragrance (optional)
Use 1 tablespoon per load.
Because Kosher salt slightly more granular and provides better abrasion than sea salt, substituting it in the borax-free recipe would probably be an improvement.
Storing the Detergent
You can store either mixture in a jar with a loose-fitting top, but the one that doesn't contain borax is apt to clump in the moist environment under your sink. To prevent this, add a desiccant consisting of 1/2 cup of bentonite clay in a child's sock. Place the sock in the jar and fill the jar with detergent. When you're out of detergent, it's also probably time to replace the sock.
Rinse With Vinegar
If your dishes are hazy after washing with your homemade detergent, it's probably because your water is very hard -- which means it's full of mineral deposits. An easy way to dissolve these is to rinse with vinegar. Fill the bottom of a cup with vinegar -- an ounce or two is all you need -- put the cup on the top shelf and run the dishwasher through a normal cycle. You can also put the vinegar in the rinse compartment, which is next to the detergent tray. The vinegar will circulate with the rinse water and dissolve the minerals that create the haze.