Is Laundry Detergent an Acid or a Base?

The exact chemical component of each laundry detergent is typically a closely guarded secret to protect brand and competitive advantage. However, industry-wide, there’s accepted wisdom on whether laundry detergent should be an acid or a base.

Modern laundry products are typically formulated to be alkaline, which helps break down oils and residues while maintaining fabric integrity.

Find out what's in the most common laundry detergent brands, what the different ingredients do, and how manufacturers maintain the acid and alkaline balance to ensure the product is a base, not an acid.

What Is the pH of Laundry Detergent?

Typically, liquid laundry detergent has a base of 7-10, and powdered detergents have a base of 8-10. The pH scale goes from 0 to 14. 7 is neutral, anything above is considered alkaline, and anything below is acidic.

Laundry detergent is intentionally alkaline (or “basic”), as this provides the best cleaning power without damaging fabrics. Bases are good at breaking down fats, oils, and metals without the requirement to rub or scrub, preserving clothing.

What Is a Base?

A base is an alkaline ingredient; there are several in most laundry detergent products, referred to as alkalies. 

Most alkalies are soluble salts that neutralize acids by creating an emulsion of particles suspended in water before rinsing. The most commonly used alkalies in laundry detergents are caustic soda, potassium hydroxide, and sodium hydroxide.

Common Ingredients in Laundry Detergents

• Alkalies: Mild alkalies include sodium bicarbonate or baking soda, as well as household ammonia and borax for greater strength. Caustic soda is a strong alkali.
• Catalytic Enzymes: Enzymes are naturally occurring proteins that allow effective cleaning at lower temperatures. They target specific stains. Common enzymes include Protease, which is gentle to fabrics while still packing a cleaning punch. Freddie laundry detergent sheets contain Protease for powerful washing and presoak-cleaning at cold temperatures.
• Fragrances: These are typically artificial, and even though they smell nice, they can contain hazardous chemicals that can irritate skin or cause other health problems.
• Optical Brighteners: These alkaline alternatives to bleach improve the appearance of whites by absorbing UV light and reflecting it back to the human eye.
• Dyes: Commonly green or blue, they create a pleasing appearance and serve no other function.
• Water Conditioners or Builders: Hard water with minerals like magnesium and calcium can neutralize acidic cleaners, making them less adept at cleaning. Water conditioners or builders in many laundry detergents soften the water to maintain detergent performance by increasing its alkalinity.
• Surfactants: Chemicals that allow the detergent to spread easily through the water also increase alkalinity.
• PH Modifiers: Used to balance the mix of bases and acids when the product combines with water.

The Role of Surfactants in Detergents

Surfactants are chemical compounds that reduce the tension between two liquids, in this case, water and detergent. They enable the detergent to spread more efficiently to soak and wet the fabrics, reducing the clothing's water repellency.

The agitation of the machine's wash cycle combines the surfactants with the water. In so doing, dirt particles, grease, and oil are broken up from the garment, lifted from the fabric, and suspended in the water to be rinsed away.

Surfactants also work by increasing the pH of the water, making it more alkaline.

Surfactants can be of natural origin, like the tea tree oil in Freddie detergent sheets. However, some liquid laundry detergents use surfactants derived from petroleum products.

The Role of Builders in Detergents

Builders enhance water quality, especially softening hard water, so the detergent can perform its job better. They prevent hard water chemicals from interfering with the cleaning process.

Builders also enhance the performance of surfactants 

The Role of pH in Different Cleaning Products

The pH scale is a chemical scale from 0 to 14 that determines whether a cleaning solution is acidic, alkaline, or pH neutral, with a score of 7. Alkaline cleaning products target organic grime, whereas acidic solutions aim to remove mineral deposits.

A neutral pH 7 cleaner would be versatile for different types of daily cleaning. However, it would struggle to tackle stubborn grease or neutralize bad odors. On the other hand, it would look after surfaces, which is the drawback of acidic cleaning products.

It's nice to think that one cleaning product can do it all, but the pH scale actually says something different. Proprietary products for various laundry issues are a better option and will take better care of your clothes.

Laundry Detergent Ingredients Influence pH Level

Most laundry detergents are bases with a pH between 7 and 10, while human skin's pH is 7.4. The pH level is determined by the detergent’s ingredients, such as surfactants, enzymes, and builders, which can vary between products. For example, enzymes like Protease (used in Freddie sheets) target protein-based stains like grass or blood, and can work in both hot and cold water.

Choose Freddie laundry sheets, designed for cleaning performance and suitable for everyday laundry use. Unlike some traditional liquid detergents, Freddie sheets are packaged without plastic jugs and contain no phosphates, brighteners, parabens, dyes, or artificial fragrances.