Soapmaking Methods Explained: Cold Process vs. Hot Process vs. Melt-and-Pour

If you’re new to soapmaking, one of the first questions you’ll face is: Which method should I use? Each technique—cold process, hot process, and melt-and-pour—has its own advantages, challenges, and creative possibilities.

This guide breaks down how each method works, what makes them different, and how to choose the one that fits your skills, goals, and style.

1. Cold Process Soapmaking

What It Is

Cold process (CP) is the most traditional method of making soap from scratch. It involves mixing oils and lye to trigger saponification, then letting the soap cure for several weeks.

How It Works

1. Melt and blend oils and butters.

2. Mix lye with water and cool the solution.

3. Combine oils and lye mixture.

4. Blend to “trace” (pudding-like consistency).

5. Add colorants, botanicals, and essential oils.

6. Pour into molds and let harden for 24–48 hours.

7. Cure for 4–6 weeks.

Pros

• Complete control over ingredients.

• Smooth, professional-looking bars.

• Ideal for intricate designs (swirls, layers, embeds).

• Long-lasting, hard bars with proper formulation.

Cons

• Requires handling lye.

• Longer curing time.

• Less forgiving—mistakes can be harder to fix.

Best For

Beginners who like DIY chemistry, makers wanting fully customizable natural soap, and artisans focused on beautiful designs.

2. Hot Process Soapmaking

What It Is

Hot process (HP) soapmaking is similar to cold process, but the mixture is cooked to speed up saponification. Many people use a slow cooker or double boiler.

How It Works

1. Combine oils and lye (like cold process).

2. Cook the mixture until it turns thick, glossy, and gel-like.

3. Add fragrance or additives after the cook.

4. Scoop or spoon the thick batter into molds.

5. Useable in 1–2 weeks (or even sooner).

Pros

• Faster turnaround—short cure time.

• More robust and forgiving; errors can often be corrected.

• Excellent for natural formulations because essential oils are added after cooking.

• Less risk of separation because saponification is complete before molding.

Cons

• Rustic, textured appearance (not ideal for smooth designs).

• Batter can be thick and harder to work with.

• Detailed swirl techniques aren’t possible.

Best For

Makers who want natural soap quickly, prefer rustic-style bars, or want maximum control over scent retention.

3. Melt-and-Pour Soapmaking

What It Is

Melt-and-pour (MP) uses a pre-made soap base that you melt, customize, and pour into molds. No lye handling is required because saponification has already happened.

How It Works

1. Cut the soap base into chunks.

2. Melt in a microwave or double boiler.

3. Add colorants, fragrance, exfoliants, or embeds.

4. Pour into molds and let cool for a few hours.

Pros

• Safest and easiest method—no lye.

• Fantastic for kids, beginners, or craft projects.

• Fast results—ready to use the same day.

• Allows for very detailed designs, layers, and embeds.

Cons

• Less control over ingredients (since the base is pre-made).

• Some bases contain additives you may not want.

• Bars may sweat (glycerin dew) in humid environments.

Best For

Beginners, crafters, hobbyists, and makers who want to focus on creativity rather than formulation.

Side-by-Side Comparison

Which Soapmaking Method Should You Choose?

• Choose cold process if you want full control, beautiful designs, and all-natural bars.

• Choose hot process if you want rustic soap quickly and prefer adding scents after saponification.

• Choose melt-and-pour if you want an easy, lye-free, creative crafting method.

If you’re unsure, start with melt-and-pour to learn the basics, then move on to cold process once you’re comfortable handling ingredients and equipment