Can Cold Process Soap Really Have a pH of 5–6?

The Truth Behind “pH Balanced Soap” Claims

If you’ve ever been told that a cold process soap can be made with a pH of 5–6, you’re not alone. This claim is widespread in the handmade and natural skincare space—but scientifically, it is not true.

In this article, we explain why cold process soap cannot be acidic, what its real pH range is, and how to make informed, honest product choices—both as a maker and as a consumer.

Understanding Soap Chemistry (In Simple Terms)

Cold process soap is made through a chemical reaction called saponification:

Oils/Fats + Sodium Hydroxide (Lye) → Soap + Glycerin

 

The soap that forms is a sodium salt of fatty acids.
By nature, this compound is alkaline.

👉 This is not a formulation choice—it is basic chemistry.

What Is the Natural pH of Cold Process Soap?

Even when perfectly made, well-cured, and superfatted, true soap stabilizes at a pH of approximately 8.0 to 10.0.

• Fresh soap: higher pH

• Cured soap (4–8 weeks): stabilizes, but remains alkaline

• Superfatting: improves mildness, not pH

✔️ A pH of 8–9 is considered normal and safe for traditional soap.

Why pH 5–6 Is Not Possible in Cold Process Soap

1. Soap Is Inherently Alkaline

Once oils react with sodium hydroxide, the resulting soap molecules cannot exist in an acidic environment. If the pH drops too low, the soap structure breaks down.

2. Adding Acids Does Not “Lower Soap pH”

Ingredients like:

• Citric acid

• Lactic acid

• Vinegar

• Fruit acids

👉 only neutralize excess lye, not the soap itself.

Adding too much acid will:

• Destroy soap molecules

• Create free fatty acids

• Make the bar soft, sticky, or unstable

• Reduce cleansing ability

3. Superfatting Does Not Change pH

Superfatting means leaving extra oil, not adding acidity.
A soap with 8–10% superfat is still alkaline.

This is one of the most common misconceptions in soap making.

So Why Do Some Products Claim “pH 5.5 Soap”?

Most products marketed as “pH 5.5 soap” are actually:

• Syndet bars (synthetic detergent bars)

• Soap-free cleansers

 

• Face washes or cleansing bars made with mild surfactants

These are not true soaps, even though they may look like soap bars.

There is nothing wrong with syndets—but they should be labeled honestly.

What Happens If You Force Soap to pH 5–6?

If a product tests at pH 5–6 and is claimed to be cold process soap, one of the following is likely true:

• It is not real soap

• The soap has partially broken down

• The pH test was done incorrectly

• The product is unstable

Such a bar may:

• Melt or sweat

• Go rancid faster

• Have poor cleansing

• Fail shelf-life expectations

Scientifically Accurate pH Ranges (Quick Reference)

Product Type	Realistic pH Range
Cold Process Soap	8.0 – 10.0
Hot Process Soap	8.0 – 10.0
Syndet Bar / Face Bar	5.0 – 6.0
Face Wash / Cleanser	5.0 – 6.0

What Can Be Done Instead? (Best Practices)

✔ Choose the Right Product Type

• Want pH 5–6? → Use a syndet cleanser

• Want traditional handmade soap? → Accept natural alkalinity

You cannot have both in one product.

✔ Improve Mildness Without Changing pH

Cold process soap can still be gentle by:

• Using lower coconut oil percentages

• Adding higher superfat (5–8%)

• Using conditioning oils (olive, rice bran, almond)

• Allowing a full cure of 6–8 weeks

✔ Educate, Don’t Mislead

Honest wording builds trust. For example:

“Traditional cold process soap with naturally alkaline pH. Follow with a moisturizer for best skin comfort.”

This is transparent, accurate, and professional.

Final Takeaway

❌ Cold process soap cannot truly have a pH of 5–6
✔ Alkalinity is part of what makes soap… soap

Understanding this difference helps:

• Brands make honest claims

• Customers choose the right products

• The natural skincare industry stay credible