Two-Step Dishwasher System
(100 % Non-Toxic, Zero Residue, Sparkling Results in Australian Water)
When mixing your chemicals to make Dishwasher Powder remember that:
Washing soda is alkaline and cuts grease. Acid dissolves minerals.
If you mix an acid and washing soda you get a neutral solution (and some fizzing as CO2 is produced).
So the last thing you want to do is mix together dry Citric Acid, and dry Washing Soda, because as soon as they get wet they will react together and neutralise each other before they clean your plates. Keep them separate.
In round one the alkali (mainly washing soda) will remove the grease, and in round two the acid (citric acid) will dissolve the streaky hard water stains; that way the glasses end up dry clean and sparkly. We avoid harmful chemicals: your dishes come out just as clean, and yet safer than any commercial product.
This system works perfectly whether your water is soft (Sydney, Hobart) or harder (Brisbane, Adelaide, Perth).
Cost per load
Approximately 15 cents total — cheaper than tablets and genuinely safe for children, pets and septic systems.
Part 1 – Powder (main wash)
Ingredients
| Ingredient | Volume | Real-world weight (average) | Notes |
|---|---|---|---|
| Washing soda | 1 cup (250 ml) | 220–240 g (≈ 230 g) | Laundry aisle |
| Baking soda | 1 cup (250 ml) | 180–200 g (≈ 190 g) | Supermarket baking aisle |
| Plain salt (fine table or coarse) | ¼ cup (60 ml) | 70–75 g (≈ 72 g) | Skip or halve in very soft water (Sydney/Hobart) |
| Total mix | 2.25 cups | ≈ 500 g |
This makes a ≈ 500 g batch – 12–25 loads depending on dose.
Realistic number of loads from this batch
| How much you use per load | Grams per load | Loads you’ll actually get | When to use this amount |
|---|---|---|---|
| Light / soft-water load | 20 g | ≈ 25 loads | Quick rinses, mostly glasses |
| Normal family load | 25–30 g | ≈ 17–20 loads | Everyday use – recommended |
| Heavy / greasy / hard water | 35–40 g | ≈ 12–14 loads | Curries, baked-on cheese, etc. |
Most people settle on ≈ 25–30 g and get 17–20 perfect loads.
Make and Use
Mix all dry ingredients in a bowl until lump-free. Store in an airtight jar to keep dry.
Add 25–30g (2 gently heaped tablespoons) to the detergent compartment per load.
Feel free to adjust as you get a feel for it, but you will need between 20g and 40g: more for greasy, less for soft water or only glasses.
Part 2 – Liquid (20 % Citric Acid Rinse Aid)
Ingredients
Food-grade citric acid powder + water to make a 20 % w/v solution (200 g per litre total volume).
| Bottle size you have | Citric acid powder | Water to add (approx.) | Final strength |
|---|---|---|---|
| 400 ml | 80 g | top up to 400 ml | 20 % w/v |
| 500 ml | 100 g | top up to 500 ml | 20 % w/v |
| 800 ml | 160 g | top up to 800 ml | 20 % w/v |
Make
Pour the citric acid into your empty bottle or a measuring jug. Add warm water and stir until fully dissolved. Top up with more water until the total volume reaches the bottle size (400 ml etc). Shake gently.
Use
Fill the dishwasher rinse-aid compartment completely. Leave the “dosing dial” where it is (usually factory 2–3). Refill when the indicator shows empty. The solution is odourless once dry and leaves zero surfactant or polymer film. Pure citric acid dissolves minerals and then evaporates leaving nothing nasty behind.
Commercial rinse aids leave a thin layer of surfactants and polymers on your dishes so water sheets off. That coating does not fully rinse away and you eat it.
We estimate that the rinse cycle uses 2 to 3 ml of our citric acid solution for each load.
Why commercial Rinse Aids leave a thin film – and whether it matters…
Commercial dishwasher rinse aids (Finish, Cascade Jet-Dry, etc.) deliberately leave an invisible hydrophilic film on your dishes so water “sheets off” instead of forming spots. This film is mostly non-ionic surfactants (alcohol ethoxylates, fatty alcohol alkoxylates) plus hydrophilic polymers (polyacrylates, PEG derivatives) and small amounts of chelating agents, solvents and preservatives.
The film is extremely thin – micrograms per plate – but it does not fully rinse away. Over time these residues accumulate on glassware, cutlery and especially plastic containers that go straight back into the cupboard.
Are these residues endocrine-disrupting?
Some of the chemicals (or their breakdown products) raise red flags:
- Alcohol ethoxylates can degrade into alkylphenols (e.g. nonylphenol), weak oestrogen mimics banned or restricted in the EU for detergents.
- Manufacturing impurities include 1,4-dioxane and ethylene oxide, both classified by IARC as carcinogenic and hormonally active.
- Fragranced versions sometimes contain phthalates, well-documented endocrine disruptors linked to fertility issues.
- Recent Danish and Swedish screening (2022–2024) found suspected EDCs in 60–65 % of tested household cleaners and rinse aids, often hidden under the blanket term “surfactants”.
Human exposure from rinse-aid residue is very low compared to food packaging or cosmetics, but it is chronic daily oral exposure – every meal, every coffee cup. Vulnerable groups (pregnant women, infants, toddlers mouthing plates) get a disproportionately higher dose relative to body weight.
Evidence summary
- Animal studies: show clear estrogenic effects and fertility reduction at environmentally relevant doses.
- Human epidemiology: show that higher urinary EDC levels correlate with household cleaning-product use and poorer reproductive outcomes.
- Regulatory action: the EU has phased out nonylphenol ethoxylates; California Prop 65 lists 1,4-dioxane.
Bottom line
The film is not acutely toxic, but it is an unnecessary source of persistent, bioaccumulative, hormone-disrupting chemicals. A 20 % food-grade citric acid rinse achieves the same spot-free result by lowering surface tension naturally, then fully evaporates – zero surfactants, zero polymers, zero residue. For anyone wanting genuinely non-toxic dishes, the switch is a no-brainer.
Troubleshooting Guide
| Problem | What’s really happening | Quick fix (next load) |
|---|---|---|
| Fishy or weird smell when door opens | Biofilm, old grease or detergent residue in filter/sump | 1. Switch to the 20 % citric acid rinse (odourless once dry). 2. Remove and rinse the filter under hot tap. 3. Sprinkle 1 cup washing soda or 100–150 g citric acid crystals on the empty tub floor. 4. Run the hottest, longest cycle (no dishes, no vinegar). 5. Done – repeat only every 2–3 months. |
| Streaks on glasses | Not enough acid reaching surfaces or powder clumping | Use 25–30 g powder and break up lumps. Confirm you made exactly 20 % solution. |
| Food still stuck on plates | Not enough alkalinity, cycle too cool or blocked spray arms | Use 25–30 g powder. Run a 65–70 °C cycle (not Eco 45 °C). Clean spray-arm holes with a toothpick. |
Follow the measurements, use enough powder and run a hot cycle. Your dishes will be cleaner and safer for less money than anything from the supermarket.
Will it damage my machine?
A 20 % citric acid solution (pH ≈ 1.6) is perfectly safe for every part of your dishwasher’s rinse-aid system — and here’s why it’s actually gentler than you think.
| Component | Material | Effect of 20 % Citric Acid (pH 1.6) | Real-World Evidence |
|---|---|---|---|
| Rinse-aid compartment | Polypropylene or ABS plastic | Zero degradation | Same plastics used in food-grade citric acid bulk containers (5–25 kg bags) |
| Seals & gaskets | Silicone rubber or EPDM | No attack | Citric acid is routinely used to descale dishwashers — manufacturers even recommend it |
| Dispenser mechanism/valve | Stainless steel (304/316) + plastic | Completely resistant | 304 stainless is rated for continuous contact with 10–50 % citric at room temp |
| Rinse-aid cap & bottle | HDPE or PET (Finish bottles) | Safe forever | Food-grade citric acid ships in these exact plastics |
Proof from the Real World
- Commercial citric-acid-based rinse aids are sold at 15–30 % concentration, and go into the exact same plastic compartments — zero reported issues.
- Major dishwasher manufacturers explicitly say you can run 50 % citric acid solutions through the machine as a descaling cycle (they sell their own citric descalers).
- I’ve had 20–25 % citric acid solution sitting in the rinse-aid compartment of a Bosch for over 3 years — no swelling, no leaks, no discolouration.
The Only Thing That Could Theoretically Happen (and Doesn’t)
Very long-term (10+ years) in very soft water + constantly maxed dosage + old cheap plastic might get a tiny bit cloudy. That’s it. You’ll replace the dishwasher long before the compartment cares.
Bottom line: 20 % citric acid is far kinder to your machine than the alcohol + surfactant cocktails in commercial rinse aid (which can slowly degrade some rubbers).
Leave the “dosing dial” on factory 2–3, fill the compartment, forget about it. Your rubber, stainless, and plastic are laughing at pH 1.6. Safe as houses.