laundry soap bar in the washing machine

How to Use Laundry Bar Soap in the Washing Machine

In a world dominated by liquid detergents and washing powders, humble laundry bar soap is a testament to traditional laundering practices.

This tried-and-tested method of washing clothes has been around for generations, providing an eco-friendly and cost-effective alternative many swear by.

However, integrating traditional laundry bar soap into modern washing machines may seem daunting for those accustomed to liquid detergents. But fear not—this comprehensive guide on how to use laundry bar soap in the washing machine is here to demystify the process.

From preparation to execution, we’ll walk you through the steps to ensure clean and fresh results.


Can You Use Bar Soap to Wash Clothes in the Washing Machine?

colorful laundry soap bars

You can use laundry bar soap in the washing machine. However, bars of soap vary in composition, so choosing a bar explicitly formulated for laundry use is essential for optimal results.

When using laundry soap in the washing machine, you’ll also have to grate the bar into smaller pieces so that they can dissolve in the wash cycle.

Even with these considerations, it is important to note that bars may not be as effective at washing clothes as other types of laundry detergents, such as laundry pods, powders, sheets, and liquids.

Even when grated, soap bars don’t dissolve as readily as these other detergent types and can leave a soapy residue on your clothes, meaning they must be rewashed.

Another time you can’t use bar soap to wash clothes is if you have a high-efficiency washer. These appliances are only compatible with specialised low-sudsing detergents.

Unfortunately, laundry soap bars create a lot of bubbles and can easily result in excess sudsing if too much soap is used.


How Do You Wash Clothes with Bar Soap in the Washing Machine?

laundry bar soap and washing machine dial

Washing clothes with bar soap in a washing machine involves preparing the soap in a way that it can be effectively used as a detergent.

With this in mind, here is a step-by-step guide on how to wash clothes using bar soap in a washing machine the right way:

Step 1: Choose your bar of laundry soap

laundry bar soap brands

Choosing the right bar of soap is crucial for achieving fresh, clean clothes. You shouldn’t use any old bar of soap, such as those used to wash your hands.

Instead, opt for laundry-specific soaps that have been formulated to remove grease and grime from a variety of fabrics.

Below are some of our favourite laundry bar soaps if you need guidance finding some top brands.

When choosing which to use, consider your laundry needs, the type of fabric you typically wash, any sensitivities or allergies, and the specific stains you commonly encounter:

  • Fels-Naptha: Fels-Naptha is a popular laundry bar soap known for its stain-fighting capabilities. It’s widely used for pre-treating stains and as a laundry booster.
  • Zote: Zote Laundry Soap is a Mexican laundry bar soap known for its effectiveness in stain removal and laundry use. We recommend the white variety if washing white or light clothes.
  • BomnKa: BomnKa Grand Canal Soap is a natural laundry soap made with coconut and other plant extracts. It has a long-lasting fragrance and can remove stains like coffee and blood.


Step 2: Grate the laundry bar soap

grated laundry bar soap

Once you’ve got your soap bar, you need to grate it into small pieces. This will help the soap dissolve and distribute more easily in the washing machine, meaning less soapy residue is left behind and resulting in more even cleaning.

You can grate the laundry soap using a regular cheese grater, but we recommend buying one intended especially for grating soap for health and hygiene reasons. Trust us—you don’t want to ingest soap accidentally!


Step 3: Add the soap to your washing machine

hand pouring liquid detergent in washing machine drawer

It’s now time to add the laundry soap to your washing machine. Here, you have two options:

  1. Use the soap as a replacement for laundry powder; or
  2. Dissolve it in water as a replacement for laundry liquid

If using bar soap as a replacement for laundry powder, simply scoop a spoonful into the drum of your washing machine.

However, despite there being a few additional steps involved, we recommend the latter liquid laundry detergent option for best results.

To turn your soap bar into a liquid, you must dissolve the grated soap in hot water to create a soap solution before adding it to the detergent drawer. You can do this by using the below steps:

  1. In a jug, mix the soap shavings with enough hot water to fully dissolve the soap.
  2. Stir well using a spook until the soap is completely dissolved.
  3. Add additional water to the soap solution to make a concentrated liquid soap mixture.
  4. Stir once again to ensure the soap is well mixed with the water.
  5. Pour the concentrated liquid soap solution into the detergent drawer.


Step 4: Load clothes & select your cycle

washing machine dial and clothes

Load your clothes into the washer as you normally would for a regular cycle, being careful not to overcrowd the machine.

Then, start the washing machine on your desired wash cycle. We recommend opting for a warm wash cycle (around 40°C), as washing at the wrong temperature can ruin your results. Here’s how:

  • Cold washes: Cold water may be unable to dissolve the bar of soap properly. If you have already dissolved your grated soap to create a liquid detergent, it can help avoid this issue. However, warm washes are still recommended for even soap distribution, especially if adding grated soap directly to the machine drum.
  • Hot washes: You might think the hotter the water, the better the soap dissolves and the cleaner your clothes. This is true for pre-dissolved soap bars placed in the detergent drawer. However, if you put the grated soap directly in the drum, it can dissolve too quickly at high temperatures and be ineffective at cleaning your clothes.

Throughout the wash cycle, observe the machine for any excess sudsing. If you notice excessive suds, you may need to reduce the amount of soap used in the future.


Step 5: Dry your clean clothes

hanging sheets or tablecloth to dry

Take your clothes from the washing machine and hang them to dry. You can hang your clothes on a clothesline, drying rack, or hangers to air dry—just ensure the area is well-ventilated and receives adequate airflow and sunlight.

Alternatively, you can use a tumble dryer if you have one. Make sure you check the care labels for your garments before throwing them in the dryer though, as the high temperatures can damage certain delicate fabrics.


What Are the Benefits of Using Laundry Bar Soap?

blue laundry bar soap

Using laundry bar soap in the washing machine is one of the best alternatives to laundry powders and detergents and has several potential benefits:

    • Cost-effectiveness: Laundry bar soap is often more economical than commercial liquid or powder detergents, making it a cost-effective option, especially for those on a tight budget. However, you can lower laundry costs in other ways, such as using colder wash cycles.
    • Environmentally friendly: Bar soaps generally have a lower environmental impact as they often come with minimal packaging, reducing plastic waste. Additionally, some laundry bar soaps are formulated with biodegradable and eco-friendly ingredients.
    • Versatility: Laundry bar soap can be used not only in washing machines but also for hand-washing, spot cleaning, and pre-treating stains. It offers a versatile solution for all your laundry care needs.
    • Gentleness: Some laundry bar soaps are formulated to be gentle on fabrics, making them suitable for washing delicate or sensitive clothing items. Many are also made from natural ingredients, which is great if you’re looking for products with fewer synthetic chemicals.
    • Reduced allergens: If you or your family members have allergies or skin sensitivities, laundry bar soaps with hypoallergenic or gentle formulations can be a suitable option to avoid common irritants found in some commercial detergents.
    • DIY and homesteading: Using laundry bar soap allows for a DIY approach to laundry care, which can be appealing to those interested in homesteading, traditional practices (like these Victorian cleaning methods), or making their own laundry products.


What Are the Drawbacks of Using Laundry Bar Soap?

detergent residue on clothes and washing machine

Despite the many advantages of using laundry bar soap in the washing machine, there are several drawbacks to consider:

    • Residue on clothes: Laundry bar soap may not always dissolve completely in the water, leading to residue and build-up on clothes. This can result in a soapy or gritty feel on clothes, and you will need to launder them again to remove the residue.
    • Potential for clogging: Residue from undissolved soap doesn’t only accumulate on your clothes—it can also build up in the washing machine itself. This may clog the dispenser or other parts of the machine, potentially affecting its performance.
    • Potential staining: Some laundry bar soaps may contain ingredients that can cause staining on clothes, especially if the soap doesn’t dissolve properly or if there are high concentrations of certain components. Be cautious if washing white garments with coloured soaps.
    • Difficult to measure and control: It can be challenging to accurately measure the right amount of soap needed for a load of laundry. This may lead to overuse or underuse of soap, affecting how well your clothes are washed.
    • Potential for excess suds: Laundry bar soap can sometimes produce excessive suds in high-efficiency washing machines, leading to issues such as poor rinsing, potential damage to the machine, or overflow during the rinse cycle.
    • Limited stain removal:  Specially formulated laundry detergents contain enzymes that break down proteins, carbohydrates, and fats, whereas regular bar soaps tend to break down fats only. Specialised laundry soap bars should have better stain-busting abilities.
    • Time-consuming preparation: Grating the soap and preparing a soap solution before every wash can be labour-intensive and time-consuming, especially compared to the convenience of using pre-measured liquid or powder detergents.

grated laundry bar soap

The decision to use laundry bar soap in a washing machine ultimately depends on your personal preferences.

However, while laundry bar soap can be a viable option for washing clothes, it’s important to consider these potential disadvantages and choose a suitable detergent based on your specific washing machine type, laundry needs, and preferences.

If you experience challenges with bar soap, you may opt for commercially available liquid or powder laundry detergents, which are formulated for washing machines and offer precise measuring and effective cleaning. For help choosing one, see our guide to the best laundry detergents.