Yet, no one seems to have the time to explain the science of laundry, even though it could boost your soil removal and pH results.
Our laundry expert, Dean Constable, is filling the gap with this series on laundry practices.
The Wash Cycle
Our third topic is the wash cycle.
Wash cycles are easy to ‘set and forget’, but the individual wash cycles you program for each soil level and linen type make a substantial difference to the wash results.
How do you use best practice wash cycles to:
- hold standards for AS4146:2000 and maintain your facility’s accreditation,
- keep your residents safe and comfortable, and
- curb your costs?
By understanding the building blocks of each wash cycle, and how they differ when specific programs run.
What is a Wash Cycle?
Wash cycles are easy to define – they are what happens inside your washing machine after you begin a program.
Programmed wash cycles are built with ‘wash steps’, which are set by several defined parameters.
- Time
A wash step’s time is set based on the step’s inbuilt requirements but can be altered based on your requirements.
- Temperature
The temperature of a wash step is set in Celsius. Temperature is decided by several variables – one example is disinfection requirements.
- Water Levels
Water levels depend on the type of wash step. High water levels are used for rinsing and flushing and low levels for wash baths.
- Action
The action of a wash step refers to the rotation of the washing machine barrel. A normal wash action would be to rotate for 12 seconds and then pause for 3 seconds. A gentle wash action rotates for 3 seconds and pauses for 12.
- Soap Signals
Soap signals in a wash step communicate with chemical dispensers to prompt preset chemical dosing.
- Draining
A drain is used at the end of each wash step to remove soil and chemicals put in during the wash process.
- Extraction/Spinning
An extraction/spinning wash step is used at the end of a cycle to remove as much residual water as possible in preparation for the drying process.
The Chemistry of a Wash Cycle
To fully understand the setup of a wash cycle, we need to be familiar with the chemicals used, how and why we use them, and how they work to make laundry results better.
The PH scale is essential to understanding the chemistry detailed below. Neutral is the plain water we use every day.
Alkalis
- Where are they on the pH scale?
Alkalis are alkaline, so they have a high pH.
- What do they do?
Alkalis work at removing soils from the linen, by loosening the soil’s grip on the material. They also increase the effectiveness of bleach by increasing pH.
- Which wash step are they used in?
Alkalis are used in a pre-wash, or in the main wash step.
- Other notes
Low pH Alkalis are also available. These are used to reduce the need for rinsing steps or acid-based products to neutralise the pH.
Detergents
- Where are they on the pH scale?
Detergents are alkaline, so they have a high pH.
- What do they do?
Detergents remove soil from the linen and wash bath by sticking to the soil and carrying it away.
- Which wash step are they used in?
Detergents are used in a pre-wash, or in the main wash step.
- Other notes
While there are many forms of detergent available, it is usually made up from surfactants and enzymes.
Bleaches
- Where are they on the pH scale?
Bleaches are alkaline, so they have a high pH.
- What do they do?
Bleaches remove or hide staining by attacking the dyes and oxidizing stains so they become colourless. Bleach also kills bacteria by attacking proteins.
- Which wash step are they used in?
Bleaches are either used in the main wash step, or in a separate bleach bath.
- Other notes
There are 3 major forms of bleaches available. They are: chlorine, hydrogen peroxide, and peracetic acid.
Sours
- Where are they on the pH scale?
Sours are acid, so they have a low pH.
- What do they do?
Sours are used to balance high pH levels, by adding acid to the wash to counteract the alkaline.
- Which wash step are they used in?
Sours are used in the final rinse step of a wash cycle.
Softeners
- Where are they on the pH scale?
Softeners are acid, so they have a low pH.
- What do they do?
Softeners soften the linen by coating the fabric with electronically charged chemical. This causes the threads to stand up, making the linen feel fluffier. Softeners also add an appealing fragrance to the wash.
- Which wash step are they used in?
Softeners are introduced into the final rinse of a wash cycle.
- Other notes
Softeners are not used on all linens as it can produce a water proofing effect, which may not be preferred on certain laundry, such as mops, tablecloths, and tea towels.
All chemicals should be used at supplier’s recommendations and at levels based on linen types and soil levels.
Example of a Wash Cycle
This example includes all common wash steps. This entire wash cycle would only be used for heavily soiled linens.
- Flush
High level water step to remove any water-soluble soils before washing.
- Break Wash
Chemicals such as alkalis or detergents are added to help remove more soils prior to a wash step. (This step is only for heavily soiled linens.)
- Main wash
This step completes your heaviest washing and soil removal. It usually has the longest time programmed, with a low water level so as not to dilute the chemicals.
Alkalis, detergents, and bleaches are used in this step. This step is also where you would complete thermal disinfection.
- Bleach bath
Once all soil is removed, bleach is dosed into a low water level wash bath. (This step is only for heavily soiled or stained items.)
- Rinse
A high water level is used in this step to remove any soils and chemicals built up in the wash steps, helping bring pH levels back to neutral.
- Final Rinse
This step is the last of the rinses, again at a high water level. Chemicals added to this step include sours and softeners.
- Extract
This is the final spin to remove all water prior to the drying process. This step can have a speed of 1000rpm.
Using the above steps, you can build any type of wash cycle.
You aren’t limited to using all these steps, and you can use wash steps several times in a wash. Your wash step choices will depend on what you are washing, how soiled it is, and your laundry’s capabilities.
Summary
Understanding the science in machine wash cycles is central to getting great results from your laundry.
You should be aware of:
- The parameters a wash step is set with
- The chemicals used in a wash cycle, and how they affect results, and
- Common wash steps used to build wash cycles to your needs.
An in-depth knowledge of wash cycles gives you the ability to validate your wash results for disinfection, soil and stain removal, and pH levels.
