Did you ever want to make soap but don’t have the patience to wait weeks for it to cure? I REALLY struggle with this! If you do too, hot process soap might be your new best friend! This method speeds up the process, allowing you to use your soap much sooner than cold process soap. Plus, it has a really cool farmhouse-y rustic look.

Homemade soaps wrapped and sitting on a soap-saver bag

What is Hot Process Soap?

Hot process soap is made using heat to speed up saponification, the chemical reaction between lye and oils that creates soap. Unlike cold process soap, which takes 4–6 weeks to cure, hot process soap is technically ready to use as soon as it cools and hardens (though a short cure time improves hardness and longevity). I also find that it always has a great lather. It is also very forgiving in terms of aesthetics as, just by it’s nature, is imperfect.

Key Differences from Cold Process Soap:

Faster usability – No long curing time required.
Thicker, rustic texture – The soap has a slightly rougher look, which adds to its handmade charm.
Better scent retention – Essential oils and fragrances are added after the cook, reducing scent loss.
Great for beginners – Less risk of lye-heavy soap because the cook process ensures full saponification.

Why You’ll Love Hot Process Soap

It’s ready to use much faster! No more waiting weeks for it to cure.
Easier to customize. You can add fragrances, colors, and additives after the soap has fully cooked.
Great for experimenting. Since you can test your bars quickly, it’s a perfect method for trying out new recipes.
No wasted fragrance. Because essential oils are added after saponification, they last longer.

What You Need to Get Started

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Ingredients:

Base Oils: Common choices include olive oil, coconut oil, palm oil, tallow, or lard.
Lye (Sodium Hydroxide): The essential ingredient that turns oils into soap. If lye scares you, we discuss this further in this post. I can’t say enough good things about Essential Depot. Good people, great prices. I buy in bulk, but you can get a single bottle here.
Water or Alternative Liquid: Distilled water, milk, herbal teas, or beer.
Optional Additives: Essential oils, fragrance oils, exfoliants, clays, and natural colorants.

Equipment:

Slow Cooker (Crock-Pot) – The easiest way to maintain consistent heat.
Digital Scale – You’ll need a digital scale that has grams and ounces for accurate measurements.
Heat-Resistant Mixing Bowl – For preparing the lye solution.
Stick Blender – To speed up the emulsification process, and save your arms, a stick blender will be your best friend!
Rubber Spatula – For mixing and scraping.
Thermometer – I use a digital thermometer to monitor temperatures.
Soap Mold – Silicone molds work best for easy release.

Finished loaf of beige soap with botanicals just removed from the mold after soap making.

Troubleshooting Common Hot Process Soap Issues

Soap is too thick to mold: Add a small amount of distilled water.
Lumpy or dry texture: Overcooked—reduce cooking time next batch.
Fragrance fades quickly: Use high-quality essential oils designed for hot process soap. Note the “flash point” of the oil.
Soap is still soft after molding: Needs more curing time.

Creative Variations to Try

Herbal Infused Soaps (Calendula, chamomile, lavender)
Milk-Based Soaps (Goat’s milk, coconut milk)
Exfoliating Soaps (Oatmeal, coffee grounds, pumice)
Layered or Swirled Soaps (Using natural colorants like clay or cocoa powder)

Table with pitcher of dried flowers and homemade soaps in front of a window

Frequently Asked Questions

How long does hot process soap need to cure?
- It’s safe to use immediately, but a week or two of curing helps it harden.
Can I use the same recipe as cold process soap?
- Yes, but hot process often requires slightly more water.
Does hot process soap lather as well as cold process?
- Yes! The lather depends more on the oils used than the method.

Final Thoughts & Next Steps

Hot process soap making is a fantastic way to create beautiful, handmade soap quickly. I love this method for last-minute, thoughtful handmade gifts. Whether you’re new to soap making or looking for a faster alternative to cold process, this method is easy, fun, and endlessly customizable.

Other Soap Recipes:

Have questions or want to share your results? Drop a comment below—I’d love to hear from you!

If you make this tutorial and love it, I would love if you gave it 5 stars! Tag me on Instagram @soapmakershomestead with your beautiful creation.

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Step-by-Step Guide to Hot Process Soap Making

Author Jennifer Butler

Instructions

Step 1: Safety First – Gloves, goggles, ventilation.
Step 2: Measure & Mix Your Lye Water – Always pour lye into water. NEVER the other way around. Always remember to "Make it snow on the lake."
Step 3: Melt & Prepare Oils – Get them ready in the crockpot.
Step 4: Blend to Trace – Use a stick blender to emulsify.
Step 5: Cook the Soap – To understand what to look for read notes on "gel phases" below.
Step 6: Add Extras & Mold – Fragrance and color if desired.
Step 7: Cool & Cut – You can cut and use soap as soon as it has cooled, but it is recommend to leave it for at least a few days to allow it to harden a bit.

Notes

Gel phases:

Phase 1: the soap will turn opaque and have the consistency of ricotta cheese.
Phase 2: soap batter will take on a clear(ish) Vaseline appearance.
Phase 3: soap will take on a look similar to mashed potatoes as well as a similar texture. At this point you may spoon it into your mold.

The Ultimate Guide to Hot Process Soap Making (With Foolproof Tips!)

What is Hot Process Soap?

Why You’ll Love Hot Process Soap