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Suds are bubbles or froth normally produced during a wash cycle. Excess suds in the main wash however prevent friction, as these cushion the items and prevent them from getting clean.
Too many suds in a pre wash cycle isn’t an issue.
The main causes of excess suds are inadequate loading, incorrect detergent type for water quality and excess surfactant for the amount of soiling.
Excess suds checklist
- Detergent choice
- Soiling level
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 remove soiling.
Loading does not matter for pre wash and it is normal to see more suds during pre wash.
Inadequate loading will cause excess suds. There isn’t enough laundry to provide sufficient friction to remove soiling and stains. As the cycle continues, the laundry in the machine will further compress, and suds will further increase with agitation over time. Excess suds cushion and prevent friction, which further prevents the removal of soiling.
Overloading prevents items from getting clean because they won’t get that required friction.
To ensure loading is correct, the laundry in the machine should be loosely full when dry, and 2/3–3/4 full when wet for optimum agitation. Damp pre washed items count as dry.
Check loading approximately a third of the way into the cycle to see if loading is accurate.
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 above). 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 may result in excess suds.
To find out the water quality in your area, check your water provider’s website, council website, or Goggle your suburb.
Detergent amount (surfactant level)
Check if there are excess suds when washing other items such as clothing or linen. If there aren’t excess suds when washing other items, then potentially there is too much detergent for the main nappy wash.
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.
Bulk the 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.
Preventing 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.
- Check your water hardness and use a low sudsing detergent.
- Ensure your main wash loading is 2/3–3/4 full when wet.
- Bulk your 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 the above methods aren’t solving the excess suds, reduce your detergent quantity by 1/4–1/2 of a scoop/lid for the main wash. See the Detergent Index for detergent quantities and water hardness recommendations.
Take notice of how clean the nappies are out of the main wash. The graphic below explains why enough detergent and surfactants are necessary.
How to quickly 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, pour 1/2–1 lid of fabric softener or hair conditioner down the detergent drawer (use some water to wash it down).
The cationic surfactants in the fabric softener or hair conditioner will bind to the excess anionic surfactants in the detergent, thus reducing the suds. This will allow the cycle to continue, and the fabric softener or hair conditioner 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.