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Having excess suds in a pre wash cycle isn’t an issue. However, excess suds in main wash prevent frictions, which cushions the items and prevents them from getting clean.
The main causes of excess suds are inadequate loading, incorrect detergent type for water quality and excess surfactant for the amount of soiling.
Too little in the machine will cause excess suds. Too much will prevent the items from getting clean because they won’t get that required friction.
Correct machine loading for the main wash is important because the surface area influences the amount of friction that occurs. Sufficient surface area and friction, along with detergent, heat and water are what remove soiling.
Along with surface area (enough items in the machine), the items need to be in the machine for long enough for the friction to remove the soiling. As the cycle continues, the items compress and more suds are created by the surfactant (which is why it is best to check loading at about a third of the way into the main cycle, see videos below). A standard Cottons cycle in a front loader is 2.5-3 hours.
Harder water contains more minerals than soft water. The purpose of water softeners in detergent is to bind these minerals, allowing the surfactants to effectively remove soiling. As a result, the base of powder detergents is water softener, usually sodium carbonate. Liquid detergents generally don’t contain water softeners. If powder detergents are used in soft water, in a front loader, it will generally result in excess suds.
When there is not enough soiling (sometimes the pre wash cycle is very effective), and too much surfactant for that level of soiling, excess suds are created.
Preventing and solving excess suds
Check the filter of the machine. Often small items or debris can get stuck in the filter. Blocked filters can often be the cause of excess suds.
Ensure loading is correct, the laundry in the machine should be between 2/3 and 3/4 full wet for optimum agitation. Correct machine loading for the main wash is important because the surface area influences the amount of friction that occurs. Sufficient surface area and friction, along with detergent, heat and water removes soiling.
Detergent amount (surfactant level)
- Are there excess suds when washing other items such as clothing or linen, when the loading is similar? If there aren’t excess suds when washing other items, then potentially there is too much detergent for the main nappy wash.
- Bulk main wash with at least 25% of items which are quite dirty (eg clothing with food or dirt), so that the surfactant is being used up.
- If others methods aren’t solving the suds, reduce your detergent quantity by 1/4-1/2 of a scoop/lid, for main wash. See the Detergent Index for detergent quantities.
Take notice of how clean the nappies are out of the wash, the graphic below explains why enough detergent and surfactants are necessary.
- Use a liquid detergent for soft water areas, a powder for hard water areas.
To find out the water quality in your area, check your water providers website, council website or Goggle your surburb.
How to fix a white out or suds lock
Some machines will continue to wash with excess suds, just extending the cycle to rinse them out, others will do a suds lock, waiting for them to subside before the cycle can continue. Both scenarios are annoying.
To quickly fix excess suds during the main cycle, add 1/2-1 lid of fabric softener down the detergent draw (use some water to wash it down). If there isn’t fabric softener on hand, use hair conditioner.
The cationic surfactants in the fabric softener and hair conditioner will bind to the excess anionic surfactants in the detergent, reducing the suds. This will allow the cycle to continue, and the fabric softener will wash out. See the Fabric Softener page for more info on softener use.
For more information on what is in detergents and the function of the raw materials see our information on Mainstream Detergents, Fragrance in Detergent, Enzymes, Optical Brighteners and Plant based, Sensitive & “Eco” Detergents, and the WashWise information sheet on Laundry Detergent Ingredients.